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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2012	Feb. 28, 2013	Jun. 30, 2012
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Trading Symbol	ETRM
Entity Registrant Name	EnteroMedics Inc
Entity Central Index Key	0001371217
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		55,618,270
Entity Public Float			$ 89,481,108

Consolidated Balance Sheets - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 22,308,781	$ 28,487,688
Restricted cash	200,000	200,000
Short-term investments available for sale		1,005,411
Accounts receivable	52,406
Inventory	1,271,207	1,068,623
Prepaid expenses and other current assets	571,654	804,799
Total current assets	24,404,048	31,566,521
Property and equipment, net	609,672	630,354
Other assets	1,082,765	288,980
Total assets	26,096,485	32,485,855
Current liabilities:
Current portion of notes payable	3,000,000	2,307,162
Accounts payable	340,555	434,436
Accrued expenses	3,673,609	6,373,370
Accrued interest payable	523,678	448,821
Total current liabilities	7,537,842	9,563,789
Notes payable, less current portion (net discounts of $316,028 and $216,711 at December 31, 2012 and 2011, respectively)	6,683,972	2,881,161
Total liabilities	14,221,814	12,444,950
Commitments and contingencies (note 14)
Stockholders' equity:
Common stock, $0.01 par value; 125,000,000 and 85,000,000 shares authorized at December 31, 2012 and 2011, respectively; 41,843,270 and 36,752,746 shares issued and outstanding at December 31, 2012 and 2011, respectively	418,433	367,527
Additional paid-in capital	211,628,650	196,384,995
Accumulated other comprehensive income		692
Deficit accumulated during development stage	(200,172,412)	(176,712,309)
Total stockholders' equity	11,874,671	20,040,905
Total liabilities and stockholders' equity	$ 26,096,485	$ 32,485,855

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Notes payable, less current portion, discounts	$ 316,028	$ 216,711
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	85,000,000
Common stock, shares issued	41,843,270	36,752,746
Common stock, shares outstanding	41,843,270	36,752,746

Consolidated Statements of Operations - USD ($)	12 Months Ended			120 Months Ended
Consolidated Statements of Operations - USD ($)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Sales	$ 311,493			$ 311,493
Cost of goods sold	231,520			231,520
Gross profit	79,973			79,973
Operating expenses:
Research and development	10,668,044	$ 16,673,238	$ 8,498,857	127,449,618
Selling, general and administrative	11,960,893	8,583,347	7,678,259	60,129,863
Total operating expenses	22,628,937	25,256,585	16,177,116	187,579,481
Operating loss	(22,548,964)	(25,256,585)	(16,177,116)	(187,499,508)
Other income (expense):
Interest income	9,877	12,241	5,597	4,046,140
Interest expense	(901,835)	(722,859)	(1,258,406)	(12,464,605)
Change in value of warrant liability			158,834	(3,840,622)
Other, net	(19,181)	(30,119)	(76,296)	(282,849)
Net loss	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (200,041,444)
Net loss per share-basic and diluted	$ (0.59)	$ (0.86)	$ (2.06)
Shares used to compute basic and diluted net loss per share	39,536,500	30,205,447	8,419,575

Consolidated Statements of Comprehensive Loss - USD ($)	12 Months Ended			120 Months Ended
Consolidated Statements of Comprehensive Loss - USD ($)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Net loss	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (200,041,444)
Change in unrealized gain (loss) on available for sale investments	(692)	692
Comprehensive loss	$ (23,460,795)	$ (25,996,630)	$ (17,347,387)	$ (200,041,444)

- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=20435746&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 10, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A7
-Appendix A

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 87-21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28, 29, 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

+ Details

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($)	Total	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Common Stock	Series C Convertible Preferred Stock	November 13, 2003 Convertible Bridge Notes Series B Convertible Preferred Stock	April 23, 2004 Convertible Bridge Notes Series B Convertible Preferred Stock	June 30, 2004 Convertible Bridge Notes Series B Convertible Preferred Stock	Alpha Medical, Inc. Series A Convertible Preferred Stock	Beta Medical, Inc. Series A Convertible Preferred Stock	Series C Preferred Stock	Series C Preferred Stock Series C Convertible Preferred Stock	Series B Preferred Stock	Series B Preferred Stock Series B Convertible Preferred Stock	Series A Preferred Stock	Series A Preferred Stock Series A Convertible Preferred Stock	Series A Preferred Stock Common Stock	Series A Preferred Stock Alpha Medical, Inc. Series A Convertible Preferred Stock	Series A Preferred Stock Beta Medical, Inc. Series A Convertible Preferred Stock	Common Stock	Common Stock Series A Convertible Preferred Stock	Common Stock Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Series A Convertible Preferred Stock	Additional Paid-in Capital Series B Convertible Preferred Stock	Additional Paid-in Capital Common Stock	Additional Paid-in Capital Series C Convertible Preferred Stock	Additional Paid-in Capital November 13, 2003 Convertible Bridge Notes Series B Convertible Preferred Stock	Additional Paid-in Capital April 23, 2004 Convertible Bridge Notes Series B Convertible Preferred Stock	Additional Paid-in Capital June 30, 2004 Convertible Bridge Notes Series B Convertible Preferred Stock	Additional Paid-in Capital Alpha Medical, Inc. Series A Convertible Preferred Stock	Additional Paid-in Capital Beta Medical, Inc. Series A Convertible Preferred Stock	Deferred Compensation	Deferred Compensation Common Stock	Accumulated Other Comprehensive Income	Accumulated During the Development Stage
Beginning Balance, share at Dec. 31, 2002															11,050					36,630
Cancellation of Alpha Medical, Inc. Series A convertible preferred stock and common stock upon merger with Beta Medical, Inc. effective October 1, 2003		$ (661,674)														$ (119)					$ (183)			$ (661,372)
Beginning Balance at Dec. 31, 2002	$ 20,000														$ 110					$ 366			$ 622,872													$ (603,348)
Cancellation of Alpha Medical, Inc. Series A convertible preferred stock and common stock upon merger with Beta Medical, Inc. effective October 1, 2003 (in shares)																(11,936)					(18,315)
Issuance of Series A convertible preferred stock		661,674														$ 110								661,564
Issuance of Series A convertible preferred stock (in shares)																10,989
Warrants issued for the purchase of shares of common stock in for cash						$ 107																						$ 107
Stock issued (in shares)																		6,410	15,568	19,229
Stock Issued	10,500								$ 350,000	$ 850,000								$ 64	$ 156	$ 192			10,308								$ 349,936	$ 849,844
Net loss	(1,900,288)																																			(1,900,288)
Ending Balance, share at Dec. 31, 2003															32,081					37,544
Ending Balance at Dec. 31, 2003	(669,681)														$ 321					$ 375			1,833,259													(2,503,636)
Issuance of common stock options to nonemployees																										$ 3,610								$ (3,610)
Fair value of warrants related to convertible bridge notes	153,722																						153,722
Convertible preferred stock issued upon conversion of debt			$ 1,599,652											$ 676											$ 1,598,976
Convertible preferred stock issued upon conversion of debt, shares														67,615
Stock Issued			7,455,225											$ 3,191											7,452,034
Stock issued (in shares)														319,128
Warrants issued for the purchase of shares of convertible preferred stock for cash			48,720				$ 30	$ 20																	48,720				$ 30	$ 20
Amortization of deferred compensation	830																																$ 830
Net loss	(3,448,752)																																			(3,448,752)
Exercise of stock warrants		$ 187,652														$ 209								187,443
Exercise of stock warrants, shares		20,963														20,963
Ending Balance, share at Dec. 31, 2004													386,743		53,044					37,544
Ending Balance at Dec. 31, 2004	5,327,418												$ 3,867		$ 530					$ 375			11,277,814										(2,780)			(5,952,388)
Issuance of common stock options to nonemployees																							7,288										(7,288)
Stock Issued	4,738,916		2,994,782										$ 2,008	$ 1,268									4,736,908		2,993,514
Stock issued (in shares)													200,776	126,806
Warrants issued for the purchase of shares of convertible preferred stock for cash			74,636																						74,636
Common stock issued to nonemployees																						$ 376				102,124								(102,500)
Common stock issued to nonemployees, shares																						37,546
Exercise of common stock options	$ 13,450																			$ 49			13,401
Exercise of common stock options, shares	4,927																			4,927
Amortization of deferred compensation	$ 25,041																																25,041
Net loss	(11,215,191)																																			(11,215,191)
Warrants issued for the purchase of shares of common stock in for cash				$ 15,500																						15,500
Ending Balance, share at Dec. 31, 2005													714,325		53,044					80,017
Ending Balance at Dec. 31, 2005	1,974,552												$ 7,143		$ 530					$ 800			19,221,185										(87,527)			(17,167,579)
Beginning Balance, share at Dec. 31, 2005													714,325		53,044					80,017
Beginning Balance at Dec. 31, 2005	1,974,552												$ 7,143		$ 530					$ 800			19,221,185										(87,527)			(17,167,579)
Convertible preferred stock issued upon conversion of debt					$ 5,381,016							$ 1,108															$ 5,379,908
Convertible preferred stock issued upon conversion of debt, shares												110,820
Employee stock-based compensation expense	47,479																						47,479
Stock Issued	1,000,000				37,602,661						$ 206	$ 8,202											999,794				37,594,459
Nonemployee stock-based compensation expense	86,125																						86,125
Stock issued (in shares)											20,595	820,190
Warrants issued for the purchase of shares of convertible preferred stock for cash	735,438		$ 102,022																				735,438		$ 102,022
Stock warrants reclassified to convertible preferred stock warrant liability					(735,438)																						(735,438)
Common stock issued to nonemployees																				$ 5		$ 16	5,245			4,484							(5,250)	$ (4,500)
Common stock issued to nonemployees, shares																				458		1,648
Exercise of common stock options	$ 39,596																			$ 145			39,451
Exercise of common stock options, shares	14,504																			14,504
Amortization of deferred compensation	$ 30,798																																30,798
Net loss	(17,690,477)																																			(17,690,477)
Ending Balance, share at Dec. 31, 2006											951,605		714,325		53,044					96,627
Ending Balance at Dec. 31, 2006	28,573,772										$ 9,516		$ 7,143		$ 530					$ 966			63,480,152										(66,479)			(34,858,056)
Employee stock-based compensation expense	883,310																						883,310
Warrants issued for the purchase of shares of series C convertible preferred stock in valued at per warrant for debt facility commitment	197,731				550,212																		197,731				550,212
Nonemployee stock-based compensation expense	1,289,349																						1,289,349
Stock warants reclassified from convertible preferred stock warrant liability					1,090,345																						1,090,345
Warrants issued for the purchase of shares of series C convertible preferred stock in valued at per warrant for debt funding	194,716				$ 281,321																		194,716				$ 281,321
Issuance of common stock and warrants in initial public offering (IPO)	35,447,337																			$ 8,333			35,439,004
Issuance of common stock initial public offering (IPO), shares																				833,333
Reclassification of amounts due to shareholders for fractional shares upon reverse stock split	(355)																						(355)
Common stock issued to Mayo Foundation upon closing the IPO in November 2007 with a fair value of $48.30 per share	1,658,654																			$ 343			1,658,311
Common stock issued to Mayo Foundation upon closing the IPO in November 2007 with a fair value of $48.30 per share, share																				34,341
Exercise of over-allotment option by underwriters in connection with the IPO for cash	3,644,477																			$ 817			3,643,660
Exercise of over-allotment option by underwriters in connection with the IPO for cash, shares																				81,642
Exercise of common stock options	$ 21,187																			$ 59			21,128
Conversion of preferred stock to common stock											$ (9,516)		$ (7,143)		$ (530)					$ 17,480			(291)
Exercise of common stock options, shares	5,854																			5,854
Conversion of preferred stock to common stock, shares											(951,605)		(714,325)		(53,044)					1,748,030
Amortization of deferred compensation	$ 24,812																																24,812
Net loss	(28,575,348)																																			(28,575,348)
Ending Balance, share at Dec. 31, 2007																				2,799,827
Ending Balance at Dec. 31, 2007	45,281,520																			$ 27,998			108,728,593										(41,667)			(63,433,404)
Employee stock-based compensation expense	2,648,410																						2,648,410
Nonemployee stock-based compensation expense	(147,855)																						(147,855)
Exercise of common stock options	$ 65,407																			$ 169			65,238
Exercise of common stock options, shares	16,829																			16,829
Change in unrealized gain (loss) on available for sale investments	$ 12,988																																		$ 12,988
Amortization of deferred compensation	20,000																																20,000
Warrants issued for the purchase of shares of common stock for cash at per warrant	1,398,702																						1,398,702
Net loss	(37,874,028)																																			(37,874,028)
Ending Balance, share at Dec. 31, 2008																				2,816,656
Ending Balance at Dec. 31, 2008	11,405,144																			$ 28,167			112,693,088										(21,667)		12,988	(101,307,432)
Employee stock-based compensation expense	2,209,216																						2,209,216
Nonemployee stock-based compensation expense	210,075																						210,075
Exercise of common stock options	$ 37,517																			134			37,383
Exercise of common stock options, shares	13,450
Change in unrealized gain (loss) on available for sale investments	$ (12,988)																																		(12,988)
Issuance of common stock in private investment public equity offering	15,089,853																			$ 21,851			15,068,002
Issuance of common stock in private investment public equity offering, shares																				2,185,066
Amortization of deferred compensation	20,000																																20,000
Issuance of common stock in registered direct offering	4,836,385																			$ 10,268			4,826,117
Issuance of common stock in registered direct offering, shares																				1,026,845
Common stock warrants reclassified to common stock warrant liability	(1,529,670)																						(1,398,702)													(130,968)
Cashless exercise of warrants with an exercise price of per share in exchange for shares of common stock	494,652			4,750,126																$ 622		$ 1,255	494,030			4,748,871
Cashless exercise of warrants with an exercise price of per share in exchange for shares of common stock, shares																				62,244		125,470
Net loss	(31,929,200)																																			(31,929,200)
Exercise of stock options, shares																				13,450
Ending Balance, share at Dec. 31, 2009																				6,229,731
Ending Balance at Dec. 31, 2009	5,581,110																			$ 62,297			138,888,080										(1,667)			(133,367,600)
Issuance of Series A convertible preferred stock		$ 5,777,532														$ 33,943								$ 5,743,589
Employee stock-based compensation expense	2,529,355																						2,529,355
Nonemployee stock-based compensation expense	33,204																						33,204
Stock issued (in shares)																3,394,309
Exercise of common stock options	$ 23,697																			$ 86			23,611
Conversion of preferred stock to common stock																	$ (33,943)					$ 33,943
Exercise of common stock options, shares	8,586																			8,586
Conversion of preferred stock to common stock, shares																	(3,394,309)					3,394,309
Issuance of common stock in private investment public equity offering, shares																				17,020,000
Amortization of deferred compensation	$ 1,667																																$ 1,667
Issuance of common stock in registered direct offering	4,495,347																			$ 12,398			4,482,949
Issuance of common stock in registered direct offering, shares																				1,239,717
Common stock warrants reclassified to equity from common stock warrant liability	312,751																						312,751
Adjustment for fractional shares upon reverse stock split																				45
Warrants issued for the purchase of shares of common stock for cash at per warrant	424,289																						424,289
Net loss	(17,347,387)																																			(17,347,387)
Issuance of common stock in public offering	27,586,135																			$ 170,200			27,415,935
Warrants issued for the purchase of shares of common stock in for cash	100			$ 289,257																			100			$ 289,257
Ending Balance, share at Dec. 31, 2010																				27,892,388
Ending Balance at Dec. 31, 2010	29,707,057																			$ 278,924			180,143,120													(150,714,987)
Employee stock-based compensation expense	2,817,082																						2,817,082
Nonemployee stock-based compensation expense	75,614																						75,614
Exercise of common stock options	$ 2,164																			$ 11			2,153
Exercise of common stock options, shares	1,139																			1,139
Change in unrealized gain (loss) on available for sale investments	$ 692																																		692
Additional financing costs for registered public offering	(45,745)																						(45,745)
Issuance of common stock in registered direct offering	13,351,674																			$ 88,000			13,263,674
Issuance of common stock in registered direct offering, shares																				8,800,000
Net loss	(25,997,322)																																			(25,997,322)
Exercise of stock warrants	$ 129,689																			$ 592			129,097
Exercise of stock options, shares																				59,219
Ending Balance, share at Dec. 31, 2011	36,752,746																			36,752,746
Ending Balance at Dec. 31, 2011	$ 20,040,905																			$ 367,527			196,384,995												692	(176,712,309)
Employee stock-based compensation expense	4,173,132																						4,173,132
Nonemployee stock-based compensation expense	52,190																						52,190
Exercise of common stock options	$ 12,666																			$ 53			12,613
Exercise of common stock options, shares	5,219																			5,219
Change in unrealized gain (loss) on available for sale investments	$ (692)																																		$ (692)
Issuance of common stock in registered direct offering	4,682,129																			$ 22,717			4,659,412
Issuance of common stock in registered direct offering, shares																				2,271,705
Warrants issued for the purchase of shares of common stock for cash at per warrant	237,349																						237,349
Net loss	(23,460,103)																																			(23,460,103)
Exercise of stock warrants	$ 6,137,095																			$ 28,136			6,108,959
Exercise of stock warrants, shares																				2,813,600
Ending Balance, share at Dec. 31, 2012	41,843,270																			41,843,270
Ending Balance at Dec. 31, 2012	$ 11,874,671																			$ 418,433			$ 211,628,650													$ (200,172,412)

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - USD ($)		12 Months Ended
	Dec. 31, 2002	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Dec. 31, 2003
Issuance of common stock in registered direct offering				$ 3.9
Convertible preferred stock warrants, exercise price										$ 8.95
Stock issued, per share		$ 2.22			$ 7.28		$ 48
Issuance of common stock in registered direct offering for cash per share, financing costs		$ 367,871		$ 339,547	$ 92,470
Issuance of common stock and warrants to purchase number of shares of common stock			1,760,000	17,020,000
Public offering			$ 1,168,326	$ 2,198,865
Warrants issued for the purchase of stock, shares		106,746		340,400	1,092,533	233,117	2,832			7,556
Warrants issued for the purchase of stock, purchase price per share				$ 100
Issuance of common stock in public offering, financing costs					$ 806,499
Cashless exercise of warrants, shares					159,420
Common or preferred stock financing costs		$ 367,871	$ 1,214,071	$ 2,538,412			$ 4,552,663		$ 11,085	$ 94,776
Cashless exercise of warrants, per share					$ 6.9
Common stock issued to Mayo Foundation upon closing the IPO, fair value of per share							$ 48.3
Exercise of over-allotment option by underwriters in connection with the IPO for cash, financing costs							$ 274,315
Cashless exercise of warrants with an exercise price in exchange for shares of common stock, shares					125,470
Warrants issued, per share		$ 2.22				$ 7.8			$ 6.42
Exercise of common stock options, shares		5,219	1,139	8,586	13,450	16,829	5,854	14,504	4,927
Exercise of common stock options, per share		$ 1.9	$ 1.9	$ 2.76			$ 3.6	$ 2.76	$ 2.76
Exercise of common stock warrants, shares		2,813,600	59,219
Issuance of common stock options to nonemployees, common stock options									7,757	3,819
Exercise of stock warrants, per share		$ 1.9	$ 2.19
Share-based goods and nonemployee services transaction, per option									$ 0.94	$ 0.94
Issuance of common stock in public offering for cash per share			$ 1.65
August 2007
Warrants Issued for Series C Convertible Preferred Stock, per share							69.83
October 2007
Warrants Issued for Series C Convertible Preferred Stock, per share							68.76
Initial Public Offering
Stock issued, per share							$ 48
Series A Convertible Preferred Stock
Stock issued, per share				$ 1.72
Exercise of stock warrants, shares										20,963
Common or preferred stock financing costs				$ 60,679
Series B Convertible Preferred Stock
Stock issued upon conversion of convertible bridge notes, value of convertible bridge notes										$ 1,564,843
Accrued interest portion of the convertible bridge notes										$ 34,809
Stock issued, per share									$ 23.66	$ 23.66
Warrants issued for the purchase of stock, shares								5,812	11,624	1,081
Series B convertible preferred stock issued, per share										$ 23.66
Common or preferred stock financing costs									$ 5,218
Warrants issued for purchase of stock										$ 6.45
Warrants issued, per share								$ 17.55
Common Stock
Warrants issued for debt modification, shares				150,642
Warrants issued for debt modification value, per share				$ 1.92
Stock issued, per share				$ 1.75	$ 4.8
Warrants issued for the purchase of stock, shares				3,394,309					28,389
Cashless exercise of warrants, shares					104,700
Warrants issued for purchase of stock				$ 0.125					$ 0.54
Cashless exercise of warrants with an exercise price in exchange for shares of common stock, shares					62,244
Series C Convertible Preferred Stock
Stock issued upon conversion of convertible bridge notes, value of convertible bridge notes								$ 5,250,003
Accrued interest portion of the convertible bridge notes								$ 131,013
Stock issued, per share								$ 48.56
Warrants issued for the purchase of stock, shares							11,327	24,606
Warrants Issued for Series C Convertible Preferred Stock, per share							$ 48.56
Warrants issued for the purchase of shares of series C convertible preferred stock Valued per warrant for debt funding, shares							5,664
Common or preferred stock financing costs								$ 2,222,342
Warrants issued, per share							$ 49.67	$ 29.89
Series A Preferred Stock \| Series A Convertible Preferred Stock
Exercise of stock warrants, shares										20,963
November 13, 2003 Convertible Bridge Notes \| Series B Preferred Stock
Warrants issued for the purchase of stock, shares											3,919
Warrants issued for purchase of stock											$ 0.03
April 23, 2004 Convertible Bridge Notes \| Series B Convertible Preferred Stock
Warrants issued for purchase of stock										$ 0.03
June 30, 2004 Convertible Bridge Notes \| Series B Convertible Preferred Stock
Warrants issued for the purchase of stock, shares										733
Warrants issued for purchase of stock										$ 0.03
Common Stock
Stock issued, per share											0.54
Exercise of stock warrants, shares		2,813,600
Exercise of common stock options, shares		5,219	1,139	8,586		16,829	5,854	14,504	4,927
Minimum
Common stock issued to non employees, per share								$ 2.76
Exercise of common stock options, per share minimum					$ 2.76	$ 2.76
Minimum \| Common Stock
Cashless exercise of warrants, per share minimum					6.9
Maximum
Common stock issued to non employees, per share								$ 11.46
Exercise of common stock options, per share		$ 2.58
Exercise of stock warrants, per share		$ 2.19
Cashless exercise of warrants, per share maximum					23.64
Exercise of common stock options, per share maximum					$ 22.2	$ 11.46
Alpha Medical, Inc. \| Series A Preferred Stock \| Series A Convertible Preferred Stock
Stock issued, per share	$ 54.6										54.6
Alpha Medical, Inc. \| Common Stock
Stock issued, per share	0.54
Beta Medical, Inc. \| Series A Preferred Stock \| Series A Convertible Preferred Stock
Stock issued, per share	54.6										$ 54.6
Beta Medical, Inc. \| Common Stock
Stock issued, per share	$ 0.54

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended			120 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Cash flows from operating activities:
Net loss	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (200,041,444)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	226,990	303,972	375,756	2,487,028
Loss on sale of equipment	767	1,269	52,622	74,894
Stock-based compensation	4,225,322	2,892,696	2,564,226	18,688,488
Amortization of commitment fees, debt issuance costs and original issue discount	207,310	234,740	387,861	4,093,933
Amortization of short-term investment premium or discount	4,719	3,261		(300,071)
Change in value of warrant liability			(158,834)	3,840,622
Change in operating assets and liabilities:
Accounts receivable	(52,406)			(52,406)
Inventory	(202,584)	(1,068,623)		(1,271,207)
Prepaid expenses and other current assets	233,145	(368,261)	47,805	(571,654)
Other assets	(813,063)	(176,985)	(60,348)	(1,050,396)
Accounts payable	(224,562)	367,491	(109,950)	76,578
Accrued expenses	(2,699,761)	3,834,999	460,455	3,673,609
Accrued interest payable	74,857	37,329	123,187	689,500
Net cash used in operating activities	(22,479,369)	(19,935,434)	(13,664,607)	(169,662,526)
Cash flows from investing activities:
Decrease (increase) in restricted cash		6,327,031	(6,527,031)	(200,000)
Purchases of short-term investments available for sale		(5,007,980)		(19,890,213)
Maturities of short-term investments available for sale	1,000,000	4,000,000		19,854,414
Purchases of short-term investments held to maturity				(22,414,130)
Maturities of short-term investments held to maturity				22,750,000
Purchases of property and equipment	(76,394)	(252,274)	(2,592)	(2,907,616)
Net cash provided by (used in) investing activities	923,606	5,066,777	(6,529,623)	(2,807,545)
Cash flows from financing activities:
Proceeds from stock options exercised	12,666	2,164	23,697	215,684
Proceeds from warrants exercised	6,137,095	129,689		6,454,436
Proceeds from sale of common stock and warrants for purchase of common stock	5,050,000	14,520,000	35,044,283	119,404,439
Common stock financing costs	(367,871)	(1,214,071)	(2,538,412)	(9,846,301)
Payment to shareholders for fractional shares upon reverse stock split				(355)
Proceeds from sale of Series A, B and C convertible preferred stock			5,838,211	63,766,564
Series A, B and C convertible preferred stock financing costs			(60,679)	(1,658,662)
Proceeds from notes payable and convertible notes payable	5,347,807			47,993,774
Repayments on notes payable	(752,841)	(921,997)	(1,889,904)	(31,178,928)
Debt issuance costs	(50,000)			(371,799)
Net cash provided by financing activities	15,376,856	12,515,785	36,417,196	194,778,852
Net (decrease) increase in cash and cash equivalents	(6,178,907)	(2,352,872)	16,222,966	22,308,781
Cash and cash equivalents:
Beginning of period	28,487,688	30,840,560	14,617,594
End of period	22,308,781	28,487,688	30,840,560	22,308,781
Supplemental disclosure:
Interest paid	619,668	$ 450,751	738,794	7,672,568
Noncash investing and financing activities:
Cancellation of Alpha Medical, Inc. Series A convertible preferred stock and common stock				(661,674)
Issuance of Beta Medical, Inc. Series A convertible preferred stock in exchange for Alpha Medical, Inc. Series A convertible preferred stock and common stock				661,674
Value of warrants issued with debt and for debt commitment	$ 237,349		289,257	4,070,532
Value of warrants issued with sale of common and preferred stock offerings			794,869	1,684,832
Cashless exercise of warrants				5,244,778
Conversion of notes and interest payable to Series B and C convertible preferred shares				6,980,668
Options issued for deferred compensation				10,898
Common stock issued to Mayo Foundation and for deferred compensation				1,770,904
Reclassification of warrant liability			312,751	2,932,766
Conversion of convertible preferred stock to common stock			$ 33,943	$ 51,132

Formation and Business of the Company

12 Months Ended

Dec. 31, 2012

Formation and Business of the Company

(1)

Formation and Business of the Company

EnteroMedics Inc. (EnteroMedics or the Company) is developing implantable systems to treat obesity, metabolic diseases and other gastrointestinal disorders. The Company was incorporated in the state of Minnesota on December 19, 2002, originally as two separate legal entities, Alpha Medical, Inc. and Beta Medical, Inc., both of which were owned 100% by a common stockholder. Effective October 1, 2003, the two entities were combined and the combined entity changed its name to EnteroMedics Inc. The Company reincorporated in Delaware on July 22, 2004. The Company is in the development stage, as defined by the Accounting Standards Codification. Since inception the Company has devoted substantially all of its resources to recruiting personnel, developing its product technology, obtaining patents to protect its intellectual property and raising capital, and only recently has derived revenues from its primary business activity. The Company is headquartered in St. Paul, Minnesota.

EnteroMedics Europe Sárl (EnteroMedics Europe), a wholly owned subsidiary of the Company, was formed in January 2006. EnteroMedics Europe is a Swiss entity established as a means to conduct clinical trials in Switzerland. Upon establishment there were 20 shares of EnteroMedics Europe issued and outstanding with a par value of 1,000 Swiss Francs. EnteroMedics purchased 100% of the shares and then issued one share to a fiduciary agent. The one share is the property of EnteroMedics and is held by the fiduciary in a fiduciary capacity under terms of the Fiduciary Agreement. The functional currency of EnteroMedics Europe has been determined to be the U.S. Dollar.

In November 2007, the Company completed its initial public offering of common stock (IPO), issuing a total of 914,975 shares for net proceeds of approximately $39.1 million after expenses and underwriters’ discounts and commissions, and including the exercise of the underwriters’ over-allotment option.

Since inception, EnteroMedics has incurred losses through December 31, 2012 totaling approximately $200.0 million and has not generated positive cash flows from operations. The Company expects such losses to continue into the foreseeable future as it continues to develop and commercialize its technologies. The Company may need to obtain additional financing and there can be no assurance that the Company will be successful in obtaining additional financing on favorable terms, or at all. If adequate funds are not available, the Company may have to delay development or commercialization of products or license to third parties the rights to commercialize products or technologies that the Company would otherwise seek to commercialize. See Notes 7 and 8 for additional discussion of financing activities.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2012

Summary of Significant Accounting Policies

(2)

Summary of Significant Accounting Policies

Basis of Presentation

The Company has prepared the accompanying consolidated financial statements in conformity with accounting principles generally accepted in the United States of America. The Company’s fiscal year ends on December 31.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany transactions and accounts have been eliminated in consolidation.

Concentration of Credit Risk and Other Risks and Uncertainties

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and restricted cash. Cash, cash equivalents and restricted cash are primarily deposited in demand and money market accounts. At times, such deposits may be in excess of insured limits. Investments in money market funds are not considered to be bank deposits and are not insured or guaranteed by the federal deposit insurance company or other government agency. These money market funds seek to preserve the value of the investment at $1.00 per share; however, it is possible to lose money investing in these funds. The Company has not experienced any losses on its deposits of cash, cash equivalents or restricted cash.

Most of the products developed by the Company will require approval from the U.S. Food and Drug Administration (FDA) or corresponding foreign regulatory agencies prior to commercial sales. There can be no assurance the Company’s products will receive the necessary approvals. If the Company is denied approval or approval is delayed, it will have a material adverse impact on the Company.

The medical device industry is characterized by frequent and extensive litigation and administrative proceedings over patent and other intellectual property rights. Whether a product infringes a patent involves complex legal and factual issues, the determination of which is often difficult to predict, and the outcome may be uncertain until the court has entered final judgment and all appeals are exhausted. The Company’s competitors may assert that its products or the use of the Company’s products are covered by U.S. or foreign patents held by them.

Fair Value of Financial Instruments

Carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, restricted cash, prepaid expenses and other current assets, accounts payable and accrued liabilities approximate fair value due to their short maturities. The fair values of investments in debt and equity securities are disclosed in Note 3. The fair value of the Company’s long-term debt is approximately $10.0 million as of December 31, 2012 based on the present value of estimated future cash flows using a discount rate commensurate with borrowing rates available to the Company. If measured at fair value in the consolidated financial statements, long-term debt (including the current portion) would be classified as Level 2 in the fair value hierarchy.

Cash and Cash Equivalents

The Company considers highly liquid investments generally with maturities of 90 days or less when purchased to be cash equivalents. Cash equivalents are stated at cost, which approximates market value. The Company’s cash equivalents are primarily in money market funds and certificates of deposit. The Company deposits its cash and cash equivalents in high-quality credit institutions. Under terms of the Company’s notes payable agreements (see Note 7), in the event of default, the lender has the right to enforce account control agreements and restrict the Company’s access to their cash and investment accounts.

Restricted Cash

The Company had $200,000 in a cash collateral money market account as of December 31, 2012 and 2011. Pursuant to the Lease Agreement the Company entered into with Roseville Properties Management Company in July 2008, the Company was required to deliver to Roseville Properties an irrevocable, unconditional, standby letter of credit in the amount of $200,000 on the second anniversary of the commencement of lease payments. The standby letter of credit is to be maintained through October 1, 2013. The irrevocable standby letter of credit was issued by Silicon Valley Bank, who required the Company to set up a restricted cash collateral money market account to fully secure the standby letter of credit.

Short-Term Investments

The Company considers all investments with maturities greater than three months and less than one year at the time of purchase as short-term investments and classifies them as either available for sale or held to maturity. The Company also considers certain investments with maturities greater than one year but which are also held for liquidity purposes and are available for sale as short-term investments.

Available-for-sale securities are carried at fair value based on quoted market prices, with the unrealized gains and losses included in other comprehensive income within stockholders’ equity (deficit) in the consolidated balance sheets. Realized gains and losses and declines in value judged to be other than temporary on available-for-sale securities are included in interest and other income. Interest and dividends on securities classified as available for sale are included in interest income. The cost of securities sold is based on the specific identification method.

Short-term investments in debt securities which the Company has the positive intent and ability to hold to maturity are reported at cost, adjusted for premiums and discounts that are recognized in interest income, using the interest method, over the period to maturity. Unrealized losses on held-to-maturity securities reflecting a decline in value determined to be other than temporary are charged to income.

Inventory

The Company accounts for inventory at the lower of cost or market and records any long-term inventory as other assets in the consolidated balance sheets.

Property and Equipment, Net

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation of property and equipment is computed using the straight-line method over their estimated useful lives of three to seven years. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or the term of the lease. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is reflected in the consolidated statements of operations. Repairs and maintenance are expensed as incurred.

Impairment of Long-Lived Assets

The Company evaluates its long-lived assets for impairment by comparison of the carrying amounts to future net undiscounted cash flows expected to be generated by such assets when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess carrying value of the asset over the asset’s fair value or estimates of future discounted cash flows. The Company has not identified any such impairment losses to date.

Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance for deferred income tax assets is recorded when it is more likely than not that some portion or all of the deferred income tax assets will not be realized. The Company has provided a full valuation allowance against the gross deferred tax assets as of December 31, 2012 and 2011 (see Note 10). The Company’s policy is to classify interest and penalties related to income taxes as income tax expense in the consolidated statements of operations.

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a company during a period from transactions and other events and circumstances excluding transactions resulting from investment owners and distributions to owners. The difference from reported net loss for the years ended December 31, 2012 and 2011 related entirely to changes in unrealized gains (losses) on available-for-sale investments. There was no difference from reported net loss for the year ended December 31, 2010.

Revenue Recognition

The Company recognizes revenue when persuasive evidence of an arrangement exists, title or risk of loss has passed, the selling price is fixed or determinable and collection is reasonably assured. The Company sells products internationally through distributors and recognizes revenue upon sale to the distributor as these sales are considered to be final and no right of return or price protection exists. Terms of sales to international distributors are generally EXW, reflecting that goods are shipped “ex works,” in which risk of loss is assumed by the distributor at the shipping point. The Company does not provide for rights of return to customers on product sales and therefore does not record a provision for returns.

Research and Development Expenses

Research and development expenses are charged to expense as incurred. Research and development expenses include, but are not limited to, product development, clinical trial expenses, including supplies, devices, explants and revisions, regulatory expenses, payroll and other personnel expenses, materials and consulting costs.

Patent Costs

Costs associated with the submission of a patent application are expensed as incurred given the uncertainty of the patents resulting in probable future economic benefits to the Company. Patent-related legal expenses included in general and administrative costs were $278,987, $271,105 and $306,181 for the years ended December 31, 2012, 2011 and 2010, respectively, and $2,443,269 for the period from December 19, 2002 (inception) to December 31, 2012.

Derivative Instruments

The Company accounts for outstanding warrants that are not indexed to the Company’s stock or warrants issued when the Company has insufficient authorized and unissued stock available to share settle the outstanding warrants as derivative instruments, which require that the warrants be classified as a liability and measured at fair value with changes in fair value recognized currently in earnings and recorded separately in the consolidated statements of operations.

Effective January 1, 2009, the Company adopted new authoritative accounting guidance regarding the financial reporting for outstanding equity-linked financial instruments. As a result of this change in accounting guidance, the Company assessed any outstanding equity-linked financial instruments and concluded that warrants issued in November 2008 with a recorded value of $1.4 million on December 31, 2008 were to be reclassified from equity to a liability. The cumulative effect of the change in accounting principle on January 1, 2009 was a $130,968 increase to the deficit accumulated during development stage. See Note 7 for details.

Stock-Based Compensation

Prior to January 1, 2006, the Company accounted for stock-based employee compensation using the intrinsic value method and recognized the expense over the option vesting period. The intrinsic value method is calculated as the difference, if any, between the fair value of the Company’s stock and the exercise price on the date of the grant. The Company also followed the minimum value disclosure provisions.

Effective January 1, 2006, the Company adopted the fair value method of accounting for share-based payments, which superseded the previous accounting method, and requires compensation expense to be recognized using a fair-value-based method for costs related to all share-based payments including stock options. Companies are required to estimate the fair value of share-based payment awards on the date of grant using an option-pricing model. The Company adopted the new provisions using the prospective transition method, which requires that for nonpublic entities that used the minimum value method for either pro forma or financial statement recognition purposes, to apply the new accounting provisions only to option grants or modifications to existing options that occur after the required effective date. For options granted prior to January 1, 2006, the Company has continued to apply the intrinsic value provisions on any remaining unvested awards. All option grants valued after January 1, 2006 are expensed on a straight-line basis over the vesting period.

The fair value method is applied to all share-based payment awards issued to employees and where appropriate, nonemployees, unless another source of literature applies. When determining the measurement date of a nonemployee’s share-based payment award, the Company measures the stock options at fair value and remeasures such stock options to the current fair value until the performance date has been reached.

Net Loss Per Share

Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is based on the weighted-average common shares outstanding during the period plus dilutive potential common shares calculated using the treasury stock method. Such potentially dilutive shares are excluded when the effect would be to reduce a net loss per share. The Company’s potential dilutive shares, which include outstanding common stock options, unvested common shares subject to repurchase and warrants, have not been included in the computation of diluted net loss per share for all periods as the result would be anti-dilutive.

The following table sets forth the computation of basic and diluted net loss per share for the years ended December 31, 2012, 2011 and 2010:


	Years ended December 31,
	2012			2011			2010
Numerator:
Net loss	$	(23,460,103	)	$	(25,997,322	)	$	(17,347,387	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		39,536,500			30,205,447			8,419,575
Weighted-average unvested common shares subject to repurchase		—			—			—

Denominator for net loss per common share—basic and diluted		39,536,500			30,205,447			8,419,575

Net loss per share—basic and diluted	$	(0.59	)	$	(0.86	)	$	(2.06	)

The following table sets forth the potential shares of common stock that are not included in the calculation of diluted net loss per share because to do so would be anti-dilutive as of the end of each period presented:


	December 31,
	2012		2011		2010
Stock options outstanding		7,835,533		3,470,908		812,515
Warrants to purchase common stock		21,216,447		23,923,301		22,224,718

Recently Issued Accounting Standards

In June 2011, the Financial Accounting Standards Board issued guidance on the presentation of comprehensive income in financial statements. Entities are required to present total comprehensive income either in a single, continuous statement of comprehensive income, or in two separate, but consecutive, statements. The Company adopted this standard during the first quarter of 2012 and presents net loss and other comprehensive loss in two separate, but consecutive, statements. The adoption of this standard did not have a material effect on the Company’s financial statement disclosures.

There have been no other significant changes in recent accounting pronouncements during the year ended December 31, 2012.

Short-term Investments and Fair Value Measurements

12 Months Ended

Dec. 31, 2012

Short-term Investments and Fair Value Measurements

(3)

Short-term Investments and Fair Value Measurements

Fair value of financial assets and liabilities is defined as the price that would be received to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:

•

Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

•

Level 2—Quoted prices for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active or model-derived valuations for which all significant inputs are observable, either directly or indirectly.

•

Level 3—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable.

The Company’s assets that are measured at fair value on a recurring basis are classified within Level 1 or Level 2 of the fair value hierarchy. The Company does not hold any assets that are measured at fair value using Level 3 inputs. The types of instruments the Company invests in that are valued based on quoted market prices in active markets include U.S. treasury securities. Such instruments are classified by the company within Level 1 of the fair value hierarchy. U.S. treasuries are valued using unadjusted quoted prices for identical assets in active markets that the Company can access.

The types of instruments the Company invests in that are valued based on quoted prices in less active markets, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency include the Company’s U.S. agency securities, commercial paper, U.S. corporate bonds and municipal obligations. Such instruments are classified by the Company within Level 2 of the fair value hierarchy. The Company values these types of assets using consensus pricing or a weighted average price, which is based on multiple pricing sources received from a variety of industry standard data providers (e.g. Bloomberg), security master files from large financial institutions, and other third-party sources. The multiple prices obtained are then used as inputs into a distribution-curve-based algorithm to determine the daily market price.

The Company did not hold any short-term investments classified as available for sale as of December 31, 2012 and did not hold any short-term investments classified as held to maturity as of December 31, 2012 and 2011.

The following table sets forth by level, within the fair value hierarchy, the Company’s financial assets accounted for at fair value as of December 31, 2011. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.

All short-term investments at December 31, 2011 were classified as available for sale and as Level 2 as follows:


	Significant Other Observable Inputs Level 2
U.S. agency securities	$	1,005,411

Total	$	1,005,411

The amortized cost and fair value of short-term investments available for sale, and the related gross unrealized gains and losses, were as follows at December 31, 2011:


			Gross Unrealized
	Cost		Gains		Losses		Fair value
U.S. agency securities	$	1,004,719	$	692	$	—	$	1,005,411

Total	$	1,004,719	$	692	$	—	$	1,005,411

Inventory

12 Months Ended

Dec. 31, 2012

Inventory

(4)

Inventory

From inception until December 2011, inventory related purchases had been used for research and development related activities and had accordingly been expensed as incurred. In December 2011, the Company began receiving Australian Register of Therapeutic Goods (ARTG) listings for components of the Maestro Rechargeable System from the Australian Therapeutic Goods Administration (TGA), with the final components being listed on the ARTG in January 2012. As a result, the Company determined certain assets were recoverable as inventory beginning in December 2011. The Company accounts for inventory at the lower of cost or market and records any long-term inventory as other assets in the consolidated balance sheets. There was approximately $862,000 and $228,000 of long-term inventory, primarily consisting of raw materials, as of December 31, 2012 and 2011, respectively.

Current inventory consists of the following as of:


	December 31,
	2012		2011
Raw materials	$	198,647	$	376,580
Work-in-process		1,051,286		692,043
Finished goods		21,274		—

Inventory	$	1,271,207	$	1,068,623

Property and Equipment

12 Months Ended

Dec. 31, 2012

Property and Equipment

(5)

Property and Equipment

Property and equipment consist of the following as of:


	December 31,
	2012			2011
Furniture and equipment	$	2,143,025		$	1,996,462
Computer hardware and software		489,478			474,236
Leasehold improvements		46,754			32,258

		2,679,257			2,502,956
Less accumulated depreciation and amortization		(2,069,585	)		(1,872,602	)

Property and equipment, net	$	609,672		$	630,354

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Accrued Expenses

12 Months Ended

Dec. 31, 2012

Accrued Expenses

(6)

Accrued Expenses

Accrued expenses consist of the following as of:


	December 31,
	2012		2011
Professional service related expenses	$	2,229,057	$	4,898,360
Payroll related expenses		1,099,713		1,169,941
Other expenses		344,839		305,069

Accrued expenses	$	3,673,609	$	6,373,370

Notes Payable

12 Months Ended

Dec. 31, 2012

Notes Payable

(7)

Notes Payable

Notes payable consists of the following as of:


	December 31,
	2012			2011
Growth capital loan dated April 16, 2012 (net discount of $316,028 at December 31, 2012)	$	9,683,972		$	—
Growth capital loan dated November 18, 2008 (net discount of $216,711 at December 31, 2011)		—			5,188,323
Less current portion		(3,000,000	)		(2,307,162	)

Total long-term debt	$	6,683,972		$	2,881,161

November 18, 2008 Debt Facility with Silicon Valley Bank, Venture Lending & Leasing V, Inc. and Compass Horizon Funding Company LLC

On November 18, 2008, the Company entered into a Loan and Security Agreement (the Prior Loan Agreement) with Silicon Valley Bank (SVB), Venture Lending & Leasing V, Inc. (a private equity fund under the management of Western Technology Investment (WTI)) and Compass Horizon Funding Company LLC (Horizon and, collectively with SVB and WTI, the Lenders), in an aggregate principal amount of up to $20.0 million. On November 21, 2008, SVB and WTI each funded a term loan in the aggregate principal amount of $10.0 million and $5.0 million, respectively. The additional $5.0 million term loan was automatically funded by Horizon on April 28, 2009 when the trading price of the Company’s common stock on the NASDAQ Global Market exceeded a target amount specified in the Prior Loan Agreement.

Interest-only payments were required on the term loans during a period beginning on the term loan funding date and continuing through June 30, 2009, followed thereafter by equal monthly payments of principal and interest over the remaining term of the term loan. Amounts borrowed under the Prior Loan Agreement had an annual interest rate equal to 12.0% during the period of interest-only payments, and thereafter, at a rate of 11.0% per annum for the remainder of the term. Per the Prior Loan Agreement, the Company was also required to make a final payment in an aggregate amount equal to 5.0% of the term loans funded by the Lenders (the Final Payment Fee).

The debt financing was collateralized by a first security priority lien on all of the Company’s assets, excluding intellectual property. The Company entered into account control agreements in order to perfect the Lenders’ first security interest in the Company’s cash and investment accounts.

On December 1, 2009, the Company voluntarily prepaid both the WTI and Horizon term loans in full. Both WTI and Horizon released their right to future interest when the term loans were paid in full.

During 2010 and 2011, the Company and SVB entered into four amendments to the Prior Loan Agreement, which modified the payment terms, annual interest rate and financial covenants. A brief summary of the four amendments is provided below.

On February 8, 2010, the Company and SVB entered into the First Amendment to the Prior Loan Agreement, which reduced the annual interest rate from 11.0% to a fixed annual rate of 10.0%, payable monthly, revised the liquidity financial covenant and added a New Capital Transaction covenant.

On July 8, 2010, the Company and SVB entered into a Second Amendment to the Prior Loan Agreement, which modified the repayment terms of the loan such that interest only payments were required through December 31, 2010 followed by 30 equal payments of principal and interest, increased the annual interest rate from 10.0% to a fixed annual rate of 11.0%, payable monthly, revised the liquidity financial covenant and added additional New Capital Transaction requirements.

On November 4, 2010, the Company and SVB entered into a Third Amendment (the Third Amendment) to the Prior Loan Agreement, which modified the New Capital Transaction covenant, suspended the liquidity financial covenant and required the Company to maintain a blocked cash collateral account with funds equal to the principal balance outstanding.

On March 3, 2011, the Company entered into a Fourth Amendment (the Fourth Amendment) to the Prior Loan Agreement with SVB. The Fourth Amendment modified the repayment terms of the term loan such that beginning April 1, 2011 through September 30, 2011, the Company was required to make interest only monthly payments on the term loan. Then, beginning on October 1, 2011, the remaining balance due on the term loan started to amortize over 30 equal payments of principal and interest, payable monthly. In addition, the Fourth Amendment amended the interest rate due effective March 1, 2011 on the remaining principal amount of the term loan from 11.0% to a fixed annual rate of 6.25%, payable monthly. The Fourth Amendment reinstated the liquidity financial covenant and eliminated SVB’s springing lien on the Company’s intellectual property, the New Capital Transactions requirement and the requirement of the Third Amendment to maintain a blocked cash collateral account with funds equal to the principal balance outstanding.

Warrants Issued

The Prior Loan Agreement required the issuance of warrants to the Lenders with an aggregate exercise price equal to 11.0% of the loan commitment. The warrants give the Lenders the option to purchase either (i) shares of the Company’s common stock with a per share exercise price equal to $9.51, or (ii) shares of the Company’s stock (including common stock) issued in an equity financing that occurred within 18 months after November 18, 2008 at the per share price of the stock sold in the financing. On November 18, 2008 (i) SVB was issued a warrant to purchase an aggregate number of shares equal to $1,100,000 divided by the per share exercise price of the warrant, (ii) WTI was issued a warrant to purchase an aggregate number of shares equal to $550,000 divided by the per share exercise price of the warrant, and (iii) Horizon received a warrant to purchase an aggregate number of shares equal to $55,000 divided by the per share exercise price of the warrant. On April 28, 2009 Horizon was issued an additional warrant to purchase an aggregate number of shares equal to $495,000 divided by the per share exercise price of the warrant in connection with the additional $5.0 million term loan that was automatically funded by Horizon pursuant to the Prior Loan Agreement.

On November 18, 2008, the Company issued a total of 179,328 common stock warrants with an exercise price of $9.51 per share and a ten year life to the Lenders, or a calculated fair value of $1.4 million. This fair value was calculated using a Black-Scholes valuation model and the following assumptions: volatility of 78.9%, dividend rate of 0%, risk-free interest rate of 3.54% and a ten year life. The exercise price of the common stock warrants issued on November 18, 2008 was adjusted to $6.90, the price per share sold in an equity financing that closed on February 24, 2009, resulting in an additional 67,773 common stock warrants for the Lenders. On April 28, 2009, the Company issued a total of 49,460 common stock warrants with an exercise price of $10.01 per share and a ten year life to Horizon, or a calculated fair value of $542,144. This fair value was calculated using a Black-Scholes valuation model and the following assumptions: volatility of 99.1%, dividend rate of 0%, risk-free interest rate of 3.00% and a ten year life. The exercise price of the common stock warrants issued to Horizon on both November 18, 2008 and April 28, 2009 was further adjusted to $4.80, the price per share sold in an equity financing that closed October 7, 2009, resulting in an additional 57,152 common stock warrants for Horizon. The exercise price of Horizon’s outstanding common stock warrants was further adjusted to $3.90, the price per share sold in an equity financing that closed January 20, 2010 (see Note 8), resulting in an additional 26,442 common stock warrants for Horizon.

As discussed in Note 2, effective January 1, 2009, as a result of a change in accounting guidance, the Company revalued the warrants issued in November 2008 and reclassified them from equity to a liability. The fair value of the warrant liability on January 1, 2009 was $1.5 million and the change in fair value was recorded as an increase to the deficit accumulated during development stage. This fair value was calculated using a weighted-average Black-Scholes valuation model and the following assumptions: volatility of 79.6%, dividend rate of 0%, risk-free interest rate of 2.24% and a remaining life of 9.88 years.

As of December 31, 2009, Horizon had outstanding 114,583 common stock warrants with an exercise price of $4.80 per share. The fair value of the warrant liability associated with these warrants was $471,585 as of December 31, 2009. This fair value was calculated using a weighted-average Black-Scholes valuation model and the following assumptions: volatility between 103.9% and 104.8%, dividend rate of 0%, risk-free interest rate of 3.84% and a remaining life between 8.89 and 9.33 years. The Company recorded a decrease of $119,904 in the change in value of the warrant liability for the year ended December 31, 2009 for this portion of the warrant liability.

As of December 31, 2010, Horizon had outstanding 141,025 common stock warrants with an exercise price of $3.90 per share. The fair value of the warrant liability associated with these warrants was $312,751 as of May 18, 2010, the date on which the warrants’ down round protection expired. This Level 3 fair value was calculated using a weighted-average Black-Scholes valuation model and the following assumptions: volatility between 113.25% and 113.33%, dividend rate of 0%, risk-free interest rate of 3.38% and a remaining life between 8.51 and 8.95 years. As a result of the down round protection expiring, on May 18, 2010 the Company recorded a decrease of $158,834 in the change in value of the warrant liability for the year ended December 31, 2010 and reclassified the warrant liability to equity.

On July 8, 2010, per the terms of the Second Amendment to the Prior Loan Agreement, SVB was issued a warrant to purchase 150,642 shares of the Company’s common stock with an exercise price of $2.10 per share.

Warrants Exercised

On September 29, 2009, SVB completed a cashless exercise of the warrants issued to them as part of the Prior Loan Agreement. SVB held a total of 159,420 common stock warrants with an exercise price of $6.90 per share. The cashless exercise of the warrants resulted in the Company issuing 125,470 shares of its common stock. The fair value of the warrant liability on the date of exercise was $4.8 million. This fair value was calculated using a weighted-average Black-Scholes valuation model and the following assumptions: volatility of 108.0%, dividend rate of 0%, risk-free interest rate of 3.29% and a remaining life of 9.14 years. As a result of the warrants being exercised, the warrant liability was reclassified to equity with $3.8 million being recorded as a change in value of the warrant liability for the year ended December 31, 2009.

On October 2, 2009, WTI completed a cashless exercise of the warrants issued to them as part of the Prior Loan Agreement entered into on November 18, 2008. WTI held a total of 79,710 common stock warrants with an exercise price of $6.90 per share. The cashless exercise of the warrants resulted in the Company issuing 59,248 shares of its common stock. The fair value of the warrant liability on the date of exercise was $494,652. This fair value was calculated using a weighted-average Black-Scholes valuation model and the following assumptions: volatility of 108.0%, dividend rate of 0%, risk-free interest rate of 3.22% and a remaining life of 9.13 years. As a result of the warrants being exercised, the warrant liability was reclassified to equity with $1,210 being recorded as a change in value of the warrant liability for the year ended December 31, 2009. WTI also completed a cashless exercise of an additional 24,990 common stock warrants with an exercise price of $23.64 per share. The cashless exercise of the warrants resulted in the Company issuing 2,996 shares of its common stock. These warrants were not included as part of the warrant liability.

April 16, 2012 Debt Facility with Silicon Valley Bank

On April 16, 2012, the Company entered into a new Loan and Security Agreement (the Loan Agreement) with SVB, pursuant to which SVB agreed to make term loans to the Company in an aggregate principal amount of up to $20.0 million ($10.0 million of which is not available as the Company did not meet the predefined primary efficacy measures of the ReCharge trial as well as certain financial objectives for 2012), on the terms and conditions set forth in the Loan Agreement. The Loan Agreement amends and restates the Prior Loan Agreement, as amended.

Pursuant to the Loan Agreement, a term loan was funded in the aggregate principal amount of $10.0 million on April 23, 2012, a portion of which was used to repay in full the outstanding debt of approximately $4.7 million. The term loan requires interest only payments monthly through March 31, 2013 followed by 30 equal payments of principal in the amount of $333,333 plus accrued interest beginning on April 1, 2013 and ending on September 1, 2015, payable monthly. Amounts borrowed under the Loan Agreement bear interest at a fixed annual rate equal to 8.0%. The Final Payment Fee from the Prior Loan Agreement will be due on September 1, 2015. The Company may voluntarily prepay the term loan in full, but not in part, and any voluntary or mandatory prepayment is subject to applicable prepayment premiums and will also include the final payment fee. The Company is required to comply with certain financial covenants that require the Company to generate certain minimum amounts of revenue from the sale of its Maestro System and to implant certain minimum numbers of Maestro Systems during cumulative quarterly measurement periods beginning with the period ended March 31, 2013 and ending with the period ending June 30, 2015. If the Company fails to meet the financial covenants, the term loan will be in default. The Company does not anticipate that it will be able to meet the financial covenants for the period ending March 31, 2013.

The Company has granted SVB a security interest in all of the Company’s assets, excluding intellectual property except with respect to all license, royalty fees and other revenues and income arising out of or relating to any of the intellectual property and all proceeds of the intellectual property. The Company also has entered into a negative pledge arrangement with SVB pursuant to which it has agreed not to encumber any of its intellectual property without SVB’s prior written consent. Pursuant to the Loan Agreement, SVB has the right to require the Company to maintain a restricted cash balance of $7.5 million in an SVB account as a result of the Company not meeting the predefined primary efficacy measures of the ReCharge trial. To date, SVB has not exercised this right.

Pursuant to the Loan Agreement, on April 16, 2012, the Company issued SVB a warrant to purchase 106,746 shares of common stock, exercisable for ten years from the date of grant, at an exercise price of $2.34 per share.

The Company was in compliance with all financial covenants related to the Loan Agreement.

Scheduled debt principal payments are as follows as of December 31, 2012:


Years Ending December 31:
2013	$	3,000,000
2014		4,000,000
2015		3,000,000

		10,000,000
Less original issue discount		(316,028	)

Notes payable, net	$	9,683,972

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Stock Sales

12 Months Ended

Dec. 31, 2012

Stock Sales

(8)

Stock Sales

Registered Direct Offering—January 2010

On January 14, 2010, the Company entered into a securities purchase agreement with certain institutional investors for the sale of 1,239,717 shares of its common stock in a registered direct offering, at a purchase price of $3.90 per share. On January 20, 2010, the offering closed and the Company received gross proceeds of $4.8 million before deducting offering expenses.

Private Placement—September 2010

On September 29, 2010, the Company entered into securities purchase agreements with several accredited investors, including certain directors and officers of the Company (see Note 13), for the sale of 3,394,309 shares of its Series A Non-Voting Convertible Preferred Stock (Preferred Stock) and 3,394,309 common stock warrants (Up Front Warrants) in a private placement transaction (the Private Placement), at a purchase price of $1.72 per share and $0.125 per warrant, respectively. On September 30, 2010, the Private Placement closed and the Company received gross proceeds of $6.3 million before deducting offering expenses.

The Up Front Warrants purchased have an exercise price per share of $2.15, or 125% of the original purchase price of the Preferred Stock and became exercisable on March 29, 2011.

On December 14, 2010, immediately following the completion of the public offering discussed below, all of the Company’s outstanding Series A Non-Voting Convertible Preferred Stock automatically converted on a 1:1 basis into 3,394,309 shares of common stock in accordance with its terms.

Public Offering—December 2010

On December 14, 2010, the Company closed a public offering, selling 17,020,000 shares of common stock together with warrants to purchase an additional 17,020,000 shares of common stock at an aggregate price of $1.75 per share and corresponding warrant, for gross proceeds of $29.8 million before deducting offering expenses. This includes the full exercise of the over-allotment option by Craig-Hallum Capital Group LLC (the Underwriter) of 2,220,000 shares of common stock together with warrants to purchase 2,220,000 shares of common stock. Certain directors and officers of the Company participated in the public offering (see Note 13). The warrants have an exercise price of $2.19 per share of common stock and became exercisable on June 13, 2011.

Pursuant to the terms of the Underwriting Agreement, the Company issued a warrant to purchase 340,400 shares of the Company’s common stock at an exercise price of $2.19 per share to the Underwriter (the Underwriter Warrant). The Underwriter purchased the Underwriter Warrant from the Company for $100 as partial compensation for its services as underwriter to the Company in connection with the Company’s public offering. The Underwriter Warrant became exercisable on June 13, 2011 and the exercise period will end five years from December 8, 2010, the date of effectiveness of the Registration Statement. The Underwriter Warrant does not allow for cashless exercise. The fair value of the Underwriter Warrant on the date of issuance was $794,869. This fair value was calculated using a Black-Scholes valuation model and the following assumptions: volatility 126.3%, dividend rate of 0%, risk-free interest rate of 2.08% and a five year life.

Public Offering—September 2011

On September 28, 2011, the Company closed a public offering, selling 8,800,000 shares of common stock, together with warrants to purchase approximately 1,760,000 shares of common stock at an aggregate price of $1.65 per share and corresponding warrant, for gross proceeds of $14.5 million before deducting offering expenses. Certain directors of the Company participated in the public offering (see Note 13).

The warrants have an exercise price of $1.90 per share of common stock and are exercisable for a period of five years from September 28, 2011. Holders of the warrants are not permitted to exercise those warrants for an amount of common stock that would result in the holder owning more than 19.99% of the Company’s common stock. The warrants may be redeemed in whole or in part at the option of the Company, at a redemption price of $0.01 per warrant at any time after any date on which the closing sale price of the common stock, as reported on the principal exchange or trading facility on which it is then traded, has equaled or exceeded $1.00 more than the exercise price of the warrants for 10 consecutive trading days. The Company is required to provide 30 days’ prior written notice to the warrantholder of the Company’s intention to redeem the warrant; provided, that the Company may not provide this notice until the earlier of (i) 30 days following the date the Company initially releases the results of the blinded portion of the ReCharge trial or (ii) June 30, 2013. The Company may not redeem any portion of a warrant if, had the holder exercised that portion of the warrant in lieu of redemption, it would have resulted in such holder owning more than 19.99% of the common stock outstanding after such exercise.

Registered Direct Offering—April 2012

On April 16, 2012, the Company entered into a securities purchase agreement with a current investor for the sale of 2,271,705 shares of its common stock in a registered direct offering, at a purchase price of $2.223 per share. On April 20, 2012, the offering closed and the Company received gross proceeds of $5.0 million before deducting estimated offering expenses.

Common Stock Purchase Agreement—October 2012

On October 4, 2012, the Company entered into a Common Stock Purchase Agreement (the Purchase Agreement) with Terrapin Opportunity, L.P. (Terrapin) pursuant to which the Company may sell up to the lesser of $45.0 million of its common stock or 8,312,122 shares of its common stock over an approximately 24-month period pursuant to the terms of the Purchase Agreement. The Company is not obligated to utilize any portion of the facility and generally remains free to enter into and consummate other equity and debt financing transactions.

The Company will determine, at its sole discretion, the timing, the dollar amount and the price per share of each draw under this facility, subject to certain conditions. When and if the Company elects to utilize the facility by delivery of a draw down notice to Terrapin, the Company will issue shares to Terrapin at a discount ranging from 4.00% to 6.80% to the volume weighted average price of the Company’s common stock over a preceding period of trading days (a Draw Down Period). The Purchase Agreement also provides that from time to time, at the Company’s sole discretion, it may grant Terrapin an option to purchase additional shares of the Company’s common stock during each Draw Down Period for an amount of shares specified by the Company based on the trading price of its common stock. Upon Terrapin’s exercise of such an option, the Company will sell to Terrapin the shares subject to the option at a price equal to the greater of (i) the daily volume weighted average price of the Company’s common stock on the day Terrapin notifies the Company of its election to exercise its option or (ii) the threshold price for the option determined by the Company, in each case less a discount ranging from 4.00% to 6.80%.

Terrapin is not required to purchase any shares at a pre-discounted purchase price below $1.25 per share, or any shares that would cause it to hold over 9.9% of the Company’s common stock. Any shares sold under this facility will be sold pursuant to a shelf registration statement declared effective by the U.S. Securities and Exchange Commission on August 29, 2012. Subject to earlier termination under certain conditions, the Purchase Agreement will terminate on November 1, 2014.

No shares of common stock have been sold under the Purchase Agreement as of December 31, 2012.

On February 27, 2013, the Company completed an additional equity financing transaction (see Note 17).

Convertible Preferred Stock

12 Months Ended

Dec. 31, 2012

Convertible Preferred Stock

(9)

Convertible Preferred Stock

The Company’s Amended and Restated Certificate of Incorporation, currently authorizes 5,000,000 shares of $0.01 par value convertible preferred stock. As of December 31, 2012 and 2011, there were no shares of convertible preferred stock issued or outstanding as all shares of Series A, Series B and Series C convertible preferred stock converted into shares of common stock upon completion of the Company’s IPO utilizing the quotient obtained by dividing the original purchase price per share of $6.5593, $3.9430 and $8.0926 by $4.2379, $3.9430 and $8.0926 per share, respectively, and all shares of Series A convertible preferred stock issued with the September 29, 2010 private placement converted to common stock on a 1:1 basis upon the December 14, 2010 closing of the Company’s public offering (see Note 8).

Income Taxes

12 Months Ended

Dec. 31, 2012

Income Taxes

(10)

Income Taxes

The Company has incurred net operating losses (NOLs) since inception. The Company has not reflected any benefit of such net operating loss carryforwards in the accompanying consolidated financial statements.

The income tax expense benefit differed from the amount computed by applying the U.S. federal income tax rate of 34% to income before income taxes as a result of the following:


	2012			2011			2010
Computed ‘expected’ tax benefit		34.0	%		34.0	%		34.0	%
Other permanent adjustments		-2.2	%		-1.8	%		-3.8	%
Research and development credit		0.0	%		1.6	%		1.2	%
Federal valuation allowance		-31.8	%		-33.8	%		-31.4	%

		0.0	%		0.0	%		0.0	%

The tax effect of temporary differences that give rise to significant portions of the deferred tax assets as of December 31 is presented below:


	2012			2011
Deferred tax assets (liabilities):
Start-up costs	$	10,367,000		$	10,751,000
Capitalized research and development costs		23,658,000			13,201,000
Reserves and accruals		3,447,000			2,299,000
Property and equipment		143,000			23,000
Research and development credit		486,000			462,000
Net operating loss carryforwards		9,185,000			5,127,000

Total gross deferred tax assets		47,286,000			31,863,000
Valuation allowance		(47,286,000	)		(31,863,000	)

Net deferred tax assets	$	—		$	—

In assessing the realization of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during periods in which those temporary differences become deductible. In addition, certain limitations imposed under the Internal Revenue Code (IRC) could further limit the Company’s realization of these deferred tax assets in the event of changes in ownership of the Company (as described below).

Based on the level of historical taxable losses and projections of future taxable income (losses) over the periods in which the deferred tax assets can be realized, management currently believes that it is more likely than not that the Company will not realize the benefits of these deductible differences. Accordingly, the Company has provided a valuation allowance against the gross deferred tax assets as of December 31, 2012 and 2011.

As of December 31, 2012, the Company has generated U.S. federal net operating loss carryforwards of approximately $70.6 million. Of this amount, approximately $22.5 million is available after the application of Section 382 limitations described below. Of the total federal net operating loss, $221,000 would result in tax benefits recorded to additional paid-in capital. The federal net operating loss carryforwards expire in the years 2022 through 2032.

The IRC imposes restrictions on the utilization of various carryforward tax attributes in the event of a change in ownership of the Company, as defined by IRC Section 382. In addition, IRC Section 382 may limit the Company’s built-in items of deduction, including capitalized start-up costs and research and development costs. During 2011, the Company completed an IRC Section 382 review and the results of this review indicate ownership changes have occurred which would cause a limitation on the utilization of carryforward attributes. The Company’s gross net operating loss carryforwards, start-up costs and research and development credits are all subject to limitation. Under these tax provisions, the limitation is applied first to any built in losses, then to any net operating losses and then to any general business credits. The Section 382 limitation and accompanying recognized built-in loss limitation is currently estimated to result in the expiration of $48.1 million of the Company’s gross federal net operating loss carryforward, as well as a write-off of $5.9 million of capitalized start-up costs, $14.2 million of capitalized research and development costs, $1.5 million of property and equipment and $2.4 million of research and development credits.

As of December 31, 2012 and 2011, there were no unrecognized tax benefits. Accordingly, a tabular reconciliation from beginning to ending periods is not provided. The Company will classify any future interest and penalties as a component of income tax expense if incurred. To date, there have been no interest or penalties charged or accrued in relation to unrecognized tax benefits.

The Company does not anticipate that the total amount of unrecognized tax benefits will change significantly in the next twelve months.

The Company is subject to federal examinations for the years 2009 forward. There are no tax examinations currently in progress.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Stock Options

12 Months Ended

Dec. 31, 2012

Stock Options

(11)

Stock Options

The Company has adopted the Amended and Restated 2003 Stock Incentive Plan (the Plan) that includes both incentive stock options and nonqualified stock options to be granted to employees, officers, consultants, independent contractors, directors and affiliates of the Company. At December 31, 2012 and 2011, according to the Plan, 12,300,000 and 4,300,000 shares, respectively, have been authorized and reserved. The board of directors establishes the terms and conditions of all stock option grants, subject to the Plan and applicable provisions of the IRC. Incentive stock options must be granted at an exercise price not less than the fair market value of the common stock on the grant date. The options granted to participants owning more than 10% of the Company’s outstanding voting stock must be granted at an exercise price not less than 110% of fair market value of the common stock on the grant date. The options expire on the date determined by the board of directors, but may not extend more than 10 years from the grant date, while incentive stock options granted to participants owning more than 10% of the Company’s outstanding voting stock expire five years from the grant date. The vesting period for employees is generally over four years. The vesting period for nonemployees is determined based on the services being provided.

On September 27, 2012, a special meeting of stockholders was held and the stockholders approved the Amended and Restated 2003 Stock Incentive Plan which (i) authorized an additional 8,000,000 shares for issuance under the Plan, (ii) extended the term of the Plan to September 27, 2022, (iii) gave the Compensation Committee the flexibility to cash out outstanding awards without participant consent in connection with a corporate transaction, (iv) modernized the provisions of the Plan with respect to Section 162(m) and Section 409A of the IRC of 1986, as amended and (v) made certain other clarification and administrative changes.

On May 5, 2011, the annual meeting of stockholders was held and the stockholders approved an amendment to the Plan to increase the number of shares authorized under the plan by 2,000,000.

On October 29, 2010, a special meeting of stockholders was held and the stockholders approved amendments to the Plan to (i) increase the number of shares authorized under the plan by 1,149,817 and (ii) allow for a one-time stock option exchange program.

The stock option exchange program was an offer by the Company to all of its employees (including executive officers) to exchange some or all of their outstanding options to purchase the Company’s common stock for fewer new options with exercise prices equal to the closing price per share of the Company’s common stock on the NASDAQ Capital Market on the date of grant (the Offer). A stock option was eligible for exchange if: (i) it had an exercise price of greater than $6.00 per share; (ii) it was not granted in connection with the performance of consulting services for the Company; (iii) it was held by an employee of the Company who was eligible to participate in the Offer; and (iv) it remained outstanding (i.e. unexpired and unexercised) as of the date of grant of the new options (such options are referred to herein as Eligible Options). There were 481,288 Eligible Options and on October 29, 2010, the Offer expired with a total of 481,288 shares of common stock underlying Eligible Options being validly tendered and not withdrawn. The Company granted new options to purchase 384,629 shares of the Company’s common stock in exchange for the cancellation of the tendered Eligible Options. The exercise price of the new stock options is $1.90 and the new options vest such that one-third of the shares underlying the option were immediately vested on the date of grant and the remaining shares vested monthly for 24 months. Each new option is a non-qualified stock option for U.S. federal income tax purposes and has a term of seven years from the date of grant.

The Eligible Options were exchanged using the below exchange ratios, which were designed to result in the fair value of the new options being approximately equal in the aggregate to the fair value of the Eligible Options that were tendered for cancellation in the exchange offer.


If the Per Share Price of the Eligible Option was		The Exchange Ratio was (Eligible Option to New Option)
$6.00 to $9.99		1.03 to 1.00
$10.00 to $19.99		1.10 to 1.00
$20.00 to $29.99		1.20 to 1.00
$30.00 to $39.99		1.26 to 1.00
$40.00 and up		1.37 to 1.00

The exchange of options pursuant to the option exchange program is characterized as a modification of the existing option awards in accordance with the fair value method of accounting for share-based payments. However, no additional expense will be recognized as the modification was value neutral. To be value neutral, the fair value of the stock options tendered as calculated immediately prior to their tender must be at least equal to the fair value of the stock options received by employees in the option exchange program. Any previously unrecognized compensation expense from the tendered stock options and incremental compensation costs associated with the new stock options received in the option exchange program will be recognized over the appropriate vesting period.

Stock option activity is as follows:


	Shares Available For Grant			Outstanding Options					Aggregate Intrinsic Value
	Shares Available For Grant			Number of Shares			Weighted-Average Exercise Price		Aggregate Intrinsic Value
Shares reserved at Plan inception		7,143			—		$	—

Balance, December 31, 2003		7,143			—			—
Shares reserved		73,260			—			—
Options granted		(57,466	)		57,466			2.76
Options exercised		—			—			—
Options cancelled		641			(641	)		2.76

Balance, December 31, 2004		23,578			56,825			2.76
Shares reserved		113,148			—			—
Options granted		(84,028	)		84,028			2.76
Options exercised		—			(4,926	)		2.76
Options cancelled		7,209			(7,209	)		2.76

Balance, December 31, 2005		59,907			128,718			2.76
Shares reserved		94,449			—			—
Options granted		(113,277	)		113,277			6.90
Options exercised		—			(14,498	)		2.76
Options cancelled		17,237			(17,237	)		2.76

Balance, December 31, 2006		58,316			210,260			5.00
Shares reserved		362,183			—			—
Options granted		(176,098	)		176,098			45.78
Options exercised		—			(5,851	)		3.65
Options cancelled		30,416			(30,416	)		74.71

Balance, December 31, 2007		274,817			350,091			19.48
Shares reserved		—			—			—
Options granted		(221,838	)		221,838			45.56
Options exercised		—			(16,820	)		3.89
Options cancelled		89,019			(89,019	)		38.69

Balance, December 31, 2008		141,998			466,090			28.79
Shares reserved		500,000			—			—
Options granted		(692,645	)		692,645			14.68
Options exercised		—			(13,437	)		2.79
Options cancelled		149,736			(149,736	)		31.20

Balance, December 31, 2009		99,089			995,562			18.96
Shares reserved		1,149,817			—			—
Options granted		(423,789	)		423,789			1.96
Options exercised		—			(8,592	)		2.76
Options cancelled		598,244			(598,244	)		25.29

Balance, December 31, 2010		1,423,361			812,515			5.60
Shares reserved		2,000,000			—			—
Options granted		(2,716,464	)		2,716,464			2.44
Options exercised		—			(1,139	)		1.90
Options cancelled		56,932			(56,932	)		3.21

Balance, December 31, 2011		763,829			3,470,908			3.17	$	—

Shares reserved		8,000,000			—			—
Options granted		(4,462,873	)		4,462,873			3.35
Options exercised		—			(5,219	)		2.43
Options cancelled		93,029			(93,029	)		2.79

Balance, December 31, 2012		4,393,985			7,835,533		$	3.28	$	1,359,840

The options outstanding, vested and currently exercisable by exercise price at December 31, 2012:


Outstanding Options and Expected to Vest							Options Exercisable and Vested
Exercise Price	Number of Shares Outstanding		Weighted-Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value		Number of Options		Weighted-Average Exercise Price		Aggregate Intrinsic Value
$0.01 to $2.00		1,038,826		7.4	$	934,943		550,576	$	1.90	$	495,518
$2.01 to $3.00		2,265,026		8.0		424,897		1,009,550		2.63		168,963
$3.01 to $5.00		4,413,799		9.6		—		610,490		3.49		—
$5.01 to $10.00		4,166		6.1		—		4,166		8.40		—
> $10.00		113,716		5.3		—		113,716		23.99		—

		7,835,533			$	1,359,840		2,288,498	$	3.76	$	664,481

Stock-Based Compensation for Nonemployees

Stock-based compensation expenses related to stock options granted to nonemployees is recognized as the stock options are earned. The Company believes that the fair value of the stock options is more reliably measurable than the fair value of the services received. The fair value of the stock options granted is calculated at each reporting date, using the Black-Scholes option-pricing model, until the award vests or there is a substantial disincentive for the nonemployee not to perform the required services. The fair value for the years ended December 31, 2012, 2011 and 2010 was calculated using the following assumptions, defined below:


	Years Ended December 31,
	2012	2011	2010
Risk-free interest rates	0.24%–2.05%	0.26%–3.45%	2.82%–3.81%
Expected life	2.00 years–9.25 years	2.04 years–9.95 years	9.01 years–9.87 years
Expected dividends	0%	0%	0%
Expected volatility	63.48%–142.25%	79.50%–123.80%	113.25%–127.93%

Stock-based compensation expense charged to operations on options granted to nonemployees for the years ended December 31, 2012, 2011 and 2010 was $52,190, $75,614 and $33,204, respectively, and $1,609,601 for the period from December 19, 2002 (inception) to December 31, 2012.

Employee Stock-Based Awards Granted on or Subsequent to January 1, 2006

On January 1, 2006, the Company adopted the fair value method of accounting for the issuance of stock-based payments, using the prospective transition method. Under this transition method, beginning January 1, 2006, compensation cost recognized includes: (a) compensation cost for all stock-based awards granted prior to, but not yet vested as of December 31, 2005, based on the intrinsic value method, and (b) compensation cost for all stock-based payments granted or modified subsequent to December 31, 2005, based on the estimated grant-date fair value.

Compensation cost for employee stock-based awards is based on the estimated grant-date fair value and is recognized over the vesting period of the applicable award on a straight-line basis. The weighted average estimated fair value of the employee stock options granted for the years ended December 31, 2012, 2011 and 2010 was $3.19, $2.13 and $0.13 per share, respectively. The weighted average estimated fair value of the employee stock options granted for the year ended December 31, 2010, excluding options granted pursuant to the option exchange program, was $1.97 per share.

The Company uses the Black-Scholes pricing model to determine the fair value of stock options. The determination of the fair value of stock-based payment awards on the date of grant is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, actual and projected employee stock option exercise behaviors, risk-free interest rates and expected dividends. The estimated grant-date fair values of the employee stock options were calculated using the Black-Scholes valuation model, based on the following assumptions for the years ended December 31, 2012, 2011 and 2010:


	Years Ended December 31,
	2012	2011	2010
Risk-free interest rates	0.90%–1.09%	1.13%–2.68%	0.89%–2.62%
Expected life	6.00 years–6.25 years	5.42 years–6.25 years	4.00 years–6.25 years
Expected dividends	0%	0%	0%
Expected volatility	137.58%–143.98%	114.80%–124.40%	113.20%–124.78%

Expected Life. The expected life is based on the “simplified” method described in the SEC Staff Accounting Bulletin, Topic 14: Share-Based Payment.

Volatility. Since the Company was a private entity for most of 2007 and a limited amount of historical data regarding the volatility of its common stock is available, the expected volatility used for 2012, 2011 and 2010 is based on both the volatility of similar entities, referred to as “guideline” companies, and the Company’s historical volatility. In evaluating similarity, the Company considered factors such as industry, stage of life cycle and size.

Risk-Free Interest Rate. The risk-free rate is based on the daily yield curve rate from the U.S. Treasury with remaining terms similar to the expected term on the options.

Dividend Yield. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.

Forfeitures. The Company is required to estimate forfeitures at the time of grant, and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense only for those awards that are expected to vest. All stock-based payment awards are amortized on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods. If the Company’s actual forfeiture rate is materially different from its estimate, the stock-based compensation expense could be significantly different from what the Company has recorded in the current period.

As of December 31, 2012 there was $15.9 million of total unrecognized compensation costs related to non-vested stock option awards granted after January 1, 2006, which are expected to be recognized over a weighted-average period of 3.24 years.

The aggregate intrinsic value of stock options (the amount by which the market price of the stock on the date of exercise exceeded the exercise price of the option) exercised during the years ended December 31, 2012, 2011 and 2010, was $3,044, $588, and $12,385, respectively.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Warrants

12 Months Ended

Dec. 31, 2012

Warrants

(12)

Warrants

Stock warrant activity is as follows:


	Common Shares			Price(1)		Series A Preferred Shares			Price(1)		Series B Preferred Shares			Price(1)		Series C Preferred Shares			Price(1)
Balance as of:
December 31, 2002		—					—					—					—
Granted		—					20,963		$	5.46		3,916		$	23.68		—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2003		—					20,963		$	5.46		3,916		$	23.68		—
Granted		—					—					16,859		$	23.68		—
Exercised		—					(20,963	)	$	8.95		—					—
Cancelled		—					—					—					—

December 31, 2004		—					—					20,775		$	23.68		—
Granted		28,385		$	2.76		—					11,624		$	23.68		—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2005		28,385		$	2.76		—					32,399		$	23.68		—
Granted		—					—					5,811		$	23.68		24,605		$	48.56
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2006		28,385		$	2.76		—					38,210		$	23.68		24,605		$	48.56
Granted		—					—					—					22,650		$	48.56
Exercised		—					—					—					—
Cancelled		—					—					—					—
Converted upon close of IPO		85,465		$	37.44		—					(38,210	)	$	23.68		(47,255	)	$	48.56

December 31, 2007		113,850		$	28.79		—					—					—
Granted(2)		179,328		$	9.51		—					—					—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2008		293,178		$	17.00		—					—					—
Granted(2)(3)		1,540,036		$	7.86		—					—					—
Exercised(3)		(264,120	)	$	8.49		—					—					—
Cancelled(3)		(236,759	)	$	9.53		—					—					—

December 31, 2009		1,332,335		$	9.44		—					—					—
Granted(2)(3)		21,046,376		$	2.19		—					—					—
Exercised		—					—					—					—
Cancelled(3)		(153,993	)	$	5.78		—					—					—

December 31, 2010		22,224,718		$	2.60		—					—					—
Granted(2)		1,759,997		$	1.90		—					—					—
Exercised		(59,219	)	$	2.19		—					—					—
Cancelled		(2,195	)	$	23.68		—					—					—

December 31, 2011		23,923,301		$	2.55		—					—					—
Granted(2)		106,746		$	2.34		—					—					—
Exercised		(2,813,600	)	$	2.18		—					—					—
Cancelled		—					—					—					—

December 31, 2012		21,216,447		$	2.60		—					—					—

(1)	Represents weighted-average exercise price per share.

(2)	See Notes 7 and 8 for discussions relating to the issuance of warrants in 2012, 2011, 2010, 2009 and 2008.

(3)	See Note 7 for discussions relating to both the cashless exercises of warrants in 2009 and the cancellation and reissuance of warrants following down round equity financings.

At December 31, 2012 and 2011, the weighted-average remaining contractual life of outstanding warrants was 3.33 and 4.32 years, respectively. All of the warrants outstanding are currently exercisable at the option of the holder into the equivalent number of shares of common stock.

Related Party Transactions

12 Months Ended

Dec. 31, 2012

Related Party Transactions

(13)

Related Party Transactions

Private Placements

As discussed in Note 8, on September 29, 2010, the Company entered into securities purchase agreements for the sale of 3,394,309 shares of its Series A Non-Voting Convertible Preferred Stock and 3,394,309 common stock warrants, in a private placement transaction. The following directors and principal stockholders, each purchased shares of preferred stock at a price of $1.72 per share and common stock warrants at a price of $0.125 per share. The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
MPM Capital		704,607		704,607	$	1,300,000
Bay City Capital		1,626,016		1,626,016		3,000,000
Aberdare Ventures		406,504		406,504		750,000
Charter Life Sciences		216,802		216,802		400,000
Paul Klingenstein		16,525		16,525		30,488
Nicholas L. Teti, Jr.		10,840		10,840		20,000

Luke Evnin, Ph.D. is a director of the Company and is a member of MPM BioVentures III LLC and a manager of MPM Asset Management Investors 2002 BVIII LLC. Carl Goldfischer, M.D. is a director of the Company and is a managing director of Bay City Capital LLC. Paul H. Klingenstein is a director of the Company and is a managing partner of the Aberdare Funds. Donald C. Harrison, M.D. served as a director of the Company until his resignation, effective May 5, 2011, and is a managing partner of Charter Life Sciences, L.P. Nicholas L. Teti, Jr. is a director of the Company.

Public Offerings

As discussed in Note 8, on December 14, 2010, the Company closed a public offering, selling 17,020,000 shares of common stock together with warrants to purchase an additional 17,020,000 shares of common stock at an aggregate price of $1.75 per share and corresponding warrant. The following officers, directors and principal stockholder, each purchased shares of common stock and warrants at an aggregate price of $1.75 per share and corresponding warrant. The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
Bay City Capital		1,700,000		1,700,000	$	2,975,000
Mark B. Knudson, Ph.D.		25,000		25,000		43,750
Greg S. Lea		10,000		10,000		17,500

As discussed in Note 8, on September 28, 2011, the Company closed a public offering, selling 8,800,000 shares of common stock together with warrants to purchase approximately 1,760,000 shares of common stock at an aggregate price of $1.65 per share and corresponding warrant. The following principal stockholder, purchased shares of common stock and warrants at a price of $1.65 per share and corresponding warrant. The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
Bay City Capital		840,000		167,999	$	1,386,000

Carl Goldfischer, M.D. is a director of the Company and is a managing director of Bay City Capital LLC. Mark B. Knudson, Ph.D. is the Company’s President, Chief Executive Officer and Chairman of the Board. Greg S. Lea is the Company’s Senior Vice President, Chief Financial Officer and Chief Operating Officer.

Consulting Agreement—Anthony Jansz

Effective June 1, 2011, the Company entered into a four year consulting agreement with Anthony Jansz, who is a member of the board of directors. Pursuant to the agreement, in exchange for consulting services provided, Mr. Jansz is entitled to receive a consulting fee of $96,000 AUD (approximately $100,000 USD as of December 31, 2012) per year and the reimbursement of reasonable expenses. Mr. Jansz also received an option to purchase 50,000 shares of common stock at $2.76 per share that vest in 48 equal monthly installments beginning on July 1, 2011. The full grant date fair value of the option grant was approximately $108,000.

On December 20, 2012, the Company entered into an amendment, effective October 1, 2012, to the consulting agreement with Anthony Jansz. Pursuant to the amendment, during the period from October 1, 2012 until June 30, 2013, Mr. Jansz agreed to commit additional time to performing consulting services for the Company. In exchange for these additional services, Mr. Jansz is entitled to receive a consulting fee of $12,000 AUD (approximately $12,000 USD as of December 31, 2012) per month from October 1, 2012 until June 30, 2013. Mr. Jansz also received an option to purchase 75,000 shares of the Company’s common stock at $2.65 per share, which vests as follows: (A) 16,667 of such 75,000 shares vested on January 22, 2013, the date of grant; (B) 16,667 of such 75,000 shares will vest on January 22, 2014; (C) 16,666 of such 75,000 shares will vest on January 22, 2015; and (D) the remaining 25,000 of such 75,000 shares will vest upon the occurrence of both (i) the Company successfully obtaining full Australian reimbursement approval for both surgeon’s fees and hospital fees for the VBLOC vagal blocking therapy and the Maestro Rechargeable System from the Australian Medical Services Advisory Committee prior to June 30, 2014 and (ii) the Company successfully obtaining device listing for the Maestro Rechargeable System on the Australian Prostheses List prior to June 30, 2014. The full grant date fair value of the option grant was approximately $153,000.

Total stock-based compensation expense recorded was approximately $23,000 and $10,000 for the years ended December 31, 2012 and 2011, respectively. In addition to the option grant, the Company paid Mr. Jansz approximately $195,000 and $67,000 in fees and expenses for consulting services provided during the years ended December 31, 2012 and 2011, respectively.

Consulting Agreement—Nicholas L. Teti, Jr.

On May 28, 2009, the Company entered into a one-year consulting agreement effective June 1, 2009 with Nicholas L. Teti, Jr., who is a member of the board of directors. Pursuant to the agreement, in exchange for consulting services provided, Mr. Teti was entitled to receive a consulting fee of $275,000 per year and the reimbursement of reasonable expenses. Mr. Teti also received an option to purchase 25,000 shares of common stock at $13.80 per share that vested in 36 equal monthly installments following the date of grant. The full grant date fair value of the option grant was approximately $314,000.

On February 10, 2010, the Company entered into a new agreement with Mr. Teti, which was effective as of February 1, 2010 and ended on July 30, 2010. In connection with entering into the new agreement, Mr. Teti and the Company agreed to terminate Mr. Teti’s prior consulting agreement. However, the options that Mr. Teti received in connection with the prior agreement continued to vest in accordance with their terms. Pursuant to this agreement, in exchange for consulting services provided, Mr. Teti was entitled to receive a consulting fee of $15,417 per month and one-third of Mr. Teti’s administrative assistant expenses. Mr. Teti also received an option to purchase 12,500 shares of common stock at $3.24 per share that vests such that one-third of the options vested immediately with the remainder vesting in 36 equal monthly installments following the date of grant.

On August 1, 2010, the Company entered into a new agreement with Mr. Teti, which was effective from August 1, 2010 through January 31, 2011. Pursuant to this agreement, in exchange for consulting services provided, Mr. Teti was entitled to receive a consulting fee of $7,000 per month and one-third of Mr. Teti’s administrative assistant expenses.

On October 1, 2010, the Company amended the August 1, 2010 agreement with Mr. Teti, which was effective from October 1, 2010 through January 31, 2011. Pursuant to this agreement, in exchange for up to ten hours of consulting services provided per month, Mr. Teti was entitled to receive a consulting fee of $175 an hour. Reimbursement of Mr. Teti’s administrative assistant expenses was eliminated with this amendment.

Total stock-based compensation expense recorded was approximately $32,000 for the year ended December 31, 2010. In addition to the option grant, the Company paid Mr. Teti approximately $184,000 in fees and expenses for consulting services rendered during the year ended December 31, 2010. There was no stock-based compensation expense recorded or other fees and expenses paid to Mr. Teti during the years ended December 31, 2012 and 2011.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39678-107864

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39691-107864

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph b
-Article 3A

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph k
-Article 4

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 57
-Paragraph 1-4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2012

Commitments and Contingencies

(14)

Commitments and Contingencies

Effective October 1, 2008 the Company entered into a seven-year non-cancelable operating lease agreement for office/warehouse space. The lease expires on September 30, 2015 with monthly base rent ranging from $19,570 to $24,643. Total rent expense recognized for the years ended December 31, 2012, 2011 and 2010 was $270,872, $270,872 and $270,872 respectively, and $1,623,928 for the period from December 19, 2002 (inception) to December 31, 2012. Facility related expenses are included as general and administrative costs on the consolidated statements of operations.

The following is a schedule of total future minimum lease payments due as of December 31, 2012:


Years ending December 31:
2013	$	285,656
2014		291,369
2015		221,789

	$	798,814

The Company is exposed to product liability claims that are inherent in the testing, production, marketing and sale of medical devices. Management believes any losses that may occur from these matters are adequately covered by insurance, and the ultimate outcome of these matters will not have a material effect on the Company’s financial position or results of operations. The Company is not currently a party to any litigation and is not aware of any pending or threatened litigation that could have a material adverse effect on the Company’s business, operating results or financial condition.

The Company is evaluating its product, the Maestro System, in human clinical trials, including the EMPOWER trial and ReCharge trial. Both of these clinical trials require patients to be followed out to 60 months. The Company is required to pay for patient follow up visits only to the extent they occur. In the event a patient does not attend a follow up visit, the Company has no financial obligation. The Company is also required to pay for explants or revisions, including potential conversions of ReCharge control devices to active devices, should a patient request or be required to have one during the course of the clinical trials. The Company has no financial obligation unless an explant, revision or conversion is requested or required. Clinical trial costs are expensed as incurred.

In 2005, EnteroMedics entered into an exclusive collaborative obesity device research and development agreement with the Mayo Foundation for Medical Education and Research (Mayo Foundation), Rochester, Minnesota. Through this agreement, EnteroMedics collaborated with a group of physicians and researchers at Mayo Clinic in the field of obesity. Under the terms of this five-year agreement, EnteroMedics and this group of Mayo specialists collectively worked toward the development of new and innovative medical devices for the treatment of obesity. The agreement also includes a similar collaboration for the development of products to address a wide variety of disorders susceptible to treatment by electrically blocking neural impulses on the vagus nerve.

Under this agreement, the Company issued 36,630 shares of common stock to the Mayo Foundation in 2005 and recorded $100,000 as deferred compensation, which was amortized over the term of the five-year agreement and was fully amortized in 2010. In accordance with the agreement, upon the closing of the IPO in November 2007, the Company was also obligated to issue 34,341 shares of common stock as consideration to the Mayo Foundation and recorded a one-time stock-based compensation expense of $1.7 million. The stock-based compensation expense is recorded on the consolidated statements of operations as research and development expense.

The Mayo Foundation received an annual $250,000 retainer fee which commenced in 2005 and continued through January 2009. The annual retainer fee paid to the Mayo Foundation is recorded on the consolidated statements of operations as research and development expense.

On March 11, 2010, the Company entered into Amendment No. 1 to the agreement with the Mayo Foundation extending the Company’s collaboration with the Mayo Foundation for a period of two years. Pursuant to the amendment, the Mayo Foundation granted the Company certain royalty-bearing, worldwide exclusive and non-exclusive licenses and committed to the joint collaboration between the Company and a designated group of physicians and researchers at the Mayo Clinic for the development and testing of products for the treatment of obesity, including devices that use electrical signaling to block the vagal nerve, and for the treatment of other gastrointestinal diseases, solely using devices that use electrical signaling to block the vagal nerve. The Mayo Foundation received an annual retainer of $100,000 in 2010 and 2011. The agreement was further amended on January 15, 2011 with Amendment No. 2. Under the terms of Amendment No. 2, the annual retainer the Mayo Foundation received for 2011 was reduced to $75,000. The agreement was further amended on February 3, 2012 with Amendment No. 3. Under the terms of Amendment No. 3, beginning in 2012 the Mayo Foundation will be reimbursed for services provided at an hourly rate only. Amendment No. 3 does not provide for additional annual retainer payments. No other terms were changed by Amendment Nos. 2 or 3.

The Company may also be obligated to pay the Mayo Foundation, contingent upon the occurrence of certain future events, earned royalty payments, including a minimum annual royalty as defined by the agreement, as amended, for the commercial sale of products developed and patented by the Mayo Foundation, jointly patented by the Company and the Mayo Foundation, or a product where the Mayo Foundation provided know-how as defined by the agreement, as amended. If no products are patented, the minimum royalty is not due.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Retirement Plan

12 Months Ended

Dec. 31, 2012

Retirement Plan

(15)

Retirement Plan

The Company has a 401(k) profit-sharing plan that provides retirement benefits to employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations. The Company’s matching is at the discretion of the Company’s board of directors. For the years ended December 31, 2012, 2011 and 2010 and for the period from December 19, 2002 (inception) to December 31, 2012, the Company did not provide any matching of employees’ contributions.

Quarterly Data

12 Months Ended

Dec. 31, 2012

Quarterly Data

(16)

Quarterly Data (unaudited)

The following table represents certain unaudited quarterly information for each of the eight quarters in the period ended December 31, 2012. In management’s opinion, this information has been prepared on the same basis as the audited consolidated financial statements and includes all the adjustments necessary to fairly state the unaudited quarterly results of operations (in thousands, except per share data).


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2012:
Net loss	$	(5,633	)	$	(4,954	)	$	(5,847	)	$	(7,027	)
Basic and diluted net loss per share	$	(0.15	)	$	(0.13	)	$	(0.14	)	$	(0.17	)
2011:
Net loss	$	(5,086	)	$	(5,557	)	$	(7,298	)	$	(8,056	)
Basic and diluted net loss per share	$	(0.18	)	$	(0.20	)	$	(0.26	)	$	(0.22	)

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Subsequent Event

12 Months Ended

Dec. 31, 2012

Subsequent Event

(17)

Subsequent Event

On February 27, 2013, the Company closed a public offering, selling 13,770,000 shares of common stock, together with warrants to purchase approximately 5,508,000 shares of common stock at an aggregate price of $0.95 per share and corresponding warrant, for gross proceeds of $13.1 million before deducting offering expenses.

The warrants have an exercise price of $1.14 per share of common stock and are exercisable for a period of five years from February 27, 2013. Holders of the warrants are not permitted to exercise those warrants for an amount of common stock that would result in the holder owning more than 19.99% of the Company’s common stock.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2012

Basis of Presentation

Basis of Presentation

Use of Estimates

Use of Estimates

Principles of Consolidation

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany transactions and accounts have been eliminated in consolidation.

Concentration of Credit Risk and Other Risks and Uncertainties

Concentration of Credit Risk and Other Risks and Uncertainties

Fair Value of Financial Instruments

Fair Value of Financial Instruments

Cash and Cash Equivalents

Cash and Cash Equivalents

Restricted Cash

Restricted Cash

Short-Term Investments

Short-Term Investments

Inventory

Inventory

The Company accounts for inventory at the lower of cost or market and records any long-term inventory as other assets in the consolidated balance sheets.

Property and Equipment, Net

Property and Equipment, Net

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets

Income Taxes

Income Taxes

Comprehensive Loss

Comprehensive Loss

Revenue Recognition

Revenue Recognition

Research and Development Expenses

Research and Development Expenses

Patent Costs

Patent Costs

Derivative Instruments

Derivative Instruments

Stock-Based Compensation

Stock-Based Compensation

Net Loss Per Share

Net Loss Per Share

The following table sets forth the computation of basic and diluted net loss per share for the years ended December 31, 2012, 2011 and 2010:


	Years ended December 31,
	2012			2011			2010
Numerator:
Net loss	$	(23,460,103	)	$	(25,997,322	)	$	(17,347,387	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		39,536,500			30,205,447			8,419,575
Weighted-average unvested common shares subject to repurchase		—			—			—

Denominator for net loss per common share—basic and diluted		39,536,500			30,205,447			8,419,575

Net loss per share—basic and diluted	$	(0.59	)	$	(0.86	)	$	(2.06	)


	December 31,
	2012		2011		2010
Stock options outstanding		7,835,533		3,470,908		812,515
Warrants to purchase common stock		21,216,447		23,923,301		22,224,718

Recently Issued Accounting Standards

Recently Issued Accounting Standards

There have been no other significant changes in recent accounting pronouncements during the year ended December 31, 2012.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Computation of Basic and Diluted Net Loss per Share

The following table sets forth the computation of basic and diluted net loss per share for the years ended December 31, 2012, 2011 and 2010:


	Years ended December 31,
	2012			2011			2010
Numerator:
Net loss	$	(23,460,103	)	$	(25,997,322	)	$	(17,347,387	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		39,536,500			30,205,447			8,419,575
Weighted-average unvested common shares subject to repurchase		—			—			—

Denominator for net loss per common share—basic and diluted		39,536,500			30,205,447			8,419,575

Net loss per share—basic and diluted	$	(0.59	)	$	(0.86	)	$	(2.06	)

Antidilutive Securities


	December 31,
	2012		2011		2010
Stock options outstanding		7,835,533		3,470,908		812,515
Warrants to purchase common stock		21,216,447		23,923,301		22,224,718

Short-term Investments and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Short-Term Investment Classified as Available for Sale and as Level Two

All short-term investments at December 31, 2011 were classified as available for sale and as Level 2 as follows:


	Significant Other Observable Inputs Level 2
U.S. agency securities	$	1,005,411

Total	$	1,005,411

Amortized Cost and Fair Value of Short-Term Investments Available for Sale and Related Gross Unrealized Gains and Losses

The amortized cost and fair value of short-term investments available for sale, and the related gross unrealized gains and losses, were as follows at December 31, 2011:


			Gross Unrealized
	Cost		Gains		Losses		Fair value
U.S. agency securities	$	1,004,719	$	692	$	—	$	1,005,411

Total	$	1,004,719	$	692	$	—	$	1,005,411

Inventory (Tables)

12 Months Ended

Dec. 31, 2012

Current Inventory

Current inventory consists of the following as of:


	December 31,
	2012		2011
Raw materials	$	198,647	$	376,580
Work-in-process		1,051,286		692,043
Finished goods		21,274		—

Inventory	$	1,271,207	$	1,068,623

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2012

Property and Equipment

Property and equipment consist of the following as of:


	December 31,
	2012			2011
Furniture and equipment	$	2,143,025		$	1,996,462
Computer hardware and software		489,478			474,236
Leasehold improvements		46,754			32,258

		2,679,257			2,502,956
Less accumulated depreciation and amortization		(2,069,585	)		(1,872,602	)

Property and equipment, net	$	609,672		$	630,354

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Accrued Expenses

Accrued expenses consist of the following as of:


	December 31,
	2012		2011
Professional service related expenses	$	2,229,057	$	4,898,360
Payroll related expenses		1,099,713		1,169,941
Other expenses		344,839		305,069

Accrued expenses	$	3,673,609	$	6,373,370

Notes Payable (Tables)

12 Months Ended

Dec. 31, 2012

Summary of Notes Payable

Notes payable consists of the following as of:


	December 31,
	2012			2011
Growth capital loan dated April 16, 2012 (net discount of $316,028 at December 31, 2012)	$	9,683,972		$	—
Growth capital loan dated November 18, 2008 (net discount of $216,711 at December 31, 2011)		—			5,188,323
Less current portion		(3,000,000	)		(2,307,162	)

Total long-term debt	$	6,683,972		$	2,881,161

Debt Future Payments

Scheduled debt principal payments are as follows as of December 31, 2012:


Years Ending December 31:
2013	$	3,000,000
2014		4,000,000
2015		3,000,000

		10,000,000
Less original issue discount		(316,028	)

Notes payable, net	$	9,683,972

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Effective Income Tax Rate Reconciliation

The income tax expense benefit differed from the amount computed by applying the U.S. federal income tax rate of 34% to income before income taxes as a result of the following:


	2012			2011			2010
Computed ‘expected’ tax benefit		34.0	%		34.0	%		34.0	%
Other permanent adjustments		-2.2	%		-1.8	%		-3.8	%
Research and development credit		0.0	%		1.6	%		1.2	%
Federal valuation allowance		-31.8	%		-33.8	%		-31.4	%

		0.0	%		0.0	%		0.0	%

Deferred Tax Assets

The tax effect of temporary differences that give rise to significant portions of the deferred tax assets as of December 31 is presented below:


	2012			2011
Deferred tax assets (liabilities):
Start-up costs	$	10,367,000		$	10,751,000
Capitalized research and development costs		23,658,000			13,201,000
Reserves and accruals		3,447,000			2,299,000
Property and equipment		143,000			23,000
Research and development credit		486,000			462,000
Net operating loss carryforwards		9,185,000			5,127,000

Total gross deferred tax assets		47,286,000			31,863,000
Valuation allowance		(47,286,000	)		(31,863,000	)

Net deferred tax assets	$	—		$	—

Stock Options (Tables)

12 Months Ended

Dec. 31, 2012

Summary of Eligible Options Tendered for Cancellation in Exchange Offer


If the Per Share Price of the Eligible Option was		The Exchange Ratio was (Eligible Option to New Option)
$6.00 to $9.99		1.03 to 1.00
$10.00 to $19.99		1.10 to 1.00
$20.00 to $29.99		1.20 to 1.00
$30.00 to $39.99		1.26 to 1.00
$40.00 and up		1.37 to 1.00

Summary of stock Option activity

Stock option activity is as follows:


	Shares Available For Grant			Outstanding Options					Aggregate Intrinsic Value
	Shares Available For Grant			Number of Shares			Weighted-Average Exercise Price		Aggregate Intrinsic Value
Shares reserved at Plan inception		7,143			—		$	—

Balance, December 31, 2003		7,143			—			—
Shares reserved		73,260			—			—
Options granted		(57,466	)		57,466			2.76
Options exercised		—			—			—
Options cancelled		641			(641	)		2.76

Balance, December 31, 2004		23,578			56,825			2.76
Shares reserved		113,148			—			—
Options granted		(84,028	)		84,028			2.76
Options exercised		—			(4,926	)		2.76
Options cancelled		7,209			(7,209	)		2.76

Balance, December 31, 2005		59,907			128,718			2.76
Shares reserved		94,449			—			—
Options granted		(113,277	)		113,277			6.90
Options exercised		—			(14,498	)		2.76
Options cancelled		17,237			(17,237	)		2.76

Balance, December 31, 2006		58,316			210,260			5.00
Shares reserved		362,183			—			—
Options granted		(176,098	)		176,098			45.78
Options exercised		—			(5,851	)		3.65
Options cancelled		30,416			(30,416	)		74.71

Balance, December 31, 2007		274,817			350,091			19.48
Shares reserved		—			—			—
Options granted		(221,838	)		221,838			45.56
Options exercised		—			(16,820	)		3.89
Options cancelled		89,019			(89,019	)		38.69

Balance, December 31, 2008		141,998			466,090			28.79
Shares reserved		500,000			—			—
Options granted		(692,645	)		692,645			14.68
Options exercised		—			(13,437	)		2.79
Options cancelled		149,736			(149,736	)		31.20

Balance, December 31, 2009		99,089			995,562			18.96
Shares reserved		1,149,817			—			—
Options granted		(423,789	)		423,789			1.96
Options exercised		—			(8,592	)		2.76
Options cancelled		598,244			(598,244	)		25.29

Balance, December 31, 2010		1,423,361			812,515			5.60
Shares reserved		2,000,000			—			—
Options granted		(2,716,464	)		2,716,464			2.44
Options exercised		—			(1,139	)		1.90
Options cancelled		56,932			(56,932	)		3.21

Balance, December 31, 2011		763,829			3,470,908			3.17	$	—

Shares reserved		8,000,000			—			—
Options granted		(4,462,873	)		4,462,873			3.35
Options exercised		—			(5,219	)		2.43
Options cancelled		93,029			(93,029	)		2.79

Balance, December 31, 2012		4,393,985			7,835,533		$	3.28	$	1,359,840

Summary of Options Outstanding, Vested and Currently Exercisable Price

The options outstanding, vested and currently exercisable by exercise price at December 31, 2012:


Outstanding Options and Expected to Vest							Options Exercisable and Vested
Exercise Price	Number of Shares Outstanding		Weighted-Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value		Number of Options		Weighted-Average Exercise Price		Aggregate Intrinsic Value
$0.01 to $2.00		1,038,826		7.4	$	934,943		550,576	$	1.90	$	495,518
$2.01 to $3.00		2,265,026		8.0		424,897		1,009,550		2.63		168,963
$3.01 to $5.00		4,413,799		9.6		—		610,490		3.49		—
$5.01 to $10.00		4,166		6.1		—		4,166		8.40		—
> $10.00		113,716		5.3		—		113,716		23.99		—

		7,835,533			$	1,359,840		2,288,498	$	3.76	$	664,481

Non Employee Stock Options

Stock Option Valuation Assumptions

The fair value for the years ended December 31, 2012, 2011 and 2010 was calculated using the following assumptions, defined below:


	Years Ended December 31,
	2012	2011	2010
Risk-free interest rates	0.24%–2.05%	0.26%–3.45%	2.82%–3.81%
Expected life	2.00 years–9.25 years	2.04 years–9.95 years	9.01 years–9.87 years
Expected dividends	0%	0%	0%
Expected volatility	63.48%–142.25%	79.50%–123.80%	113.25%–127.93%

Employee Stock Option

Stock Option Valuation Assumptions

The estimated grant-date fair values of the employee stock options were calculated using the Black-Scholes valuation model, based on the following assumptions for the years ended December 31, 2012, 2011 and 2010:


	Years Ended December 31,
	2012	2011	2010
Risk-free interest rates	0.90%–1.09%	1.13%–2.68%	0.89%–2.62%
Expected life	6.00 years–6.25 years	5.42 years–6.25 years	4.00 years–6.25 years
Expected dividends	0%	0%	0%
Expected volatility	137.58%–143.98%	114.80%–124.40%	113.20%–124.78%

Warrants (Tables)

12 Months Ended

Dec. 31, 2012

Stock Warrants Activity

Stock warrant activity is as follows:


	Common Shares			Price(1)		Series A Preferred Shares			Price(1)		Series B Preferred Shares			Price(1)		Series C Preferred Shares			Price(1)
Balance as of:
December 31, 2002		—					—					—					—
Granted		—					20,963		$	5.46		3,916		$	23.68		—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2003		—					20,963		$	5.46		3,916		$	23.68		—
Granted		—					—					16,859		$	23.68		—
Exercised		—					(20,963	)	$	8.95		—					—
Cancelled		—					—					—					—

December 31, 2004		—					—					20,775		$	23.68		—
Granted		28,385		$	2.76		—					11,624		$	23.68		—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2005		28,385		$	2.76		—					32,399		$	23.68		—
Granted		—					—					5,811		$	23.68		24,605		$	48.56
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2006		28,385		$	2.76		—					38,210		$	23.68		24,605		$	48.56
Granted		—					—					—					22,650		$	48.56
Exercised		—					—					—					—
Cancelled		—					—					—					—
Converted upon close of IPO		85,465		$	37.44		—					(38,210	)	$	23.68		(47,255	)	$	48.56

December 31, 2007		113,850		$	28.79		—					—					—
Granted(2)		179,328		$	9.51		—					—					—
Exercised		—					—					—					—
Cancelled		—					—					—					—

December 31, 2008		293,178		$	17.00		—					—					—
Granted(2)(3)		1,540,036		$	7.86		—					—					—
Exercised(3)		(264,120	)	$	8.49		—					—					—
Cancelled(3)		(236,759	)	$	9.53		—					—					—

December 31, 2009		1,332,335		$	9.44		—					—					—
Granted(2)(3)		21,046,376		$	2.19		—					—					—
Exercised		—					—					—					—
Cancelled(3)		(153,993	)	$	5.78		—					—					—

December 31, 2010		22,224,718		$	2.60		—					—					—
Granted(2)		1,759,997		$	1.90		—					—					—
Exercised		(59,219	)	$	2.19		—					—					—
Cancelled		(2,195	)	$	23.68		—					—					—

December 31, 2011		23,923,301		$	2.55		—					—					—
Granted(2)		106,746		$	2.34		—					—					—
Exercised		(2,813,600	)	$	2.18		—					—					—
Cancelled		—					—					—					—

December 31, 2012		21,216,447		$	2.60		—					—					—

(1)	Represents weighted-average exercise price per share.

(2)	See Notes 7 and 8 for discussions relating to the issuance of warrants in 2012, 2011, 2010, 2009 and 2008.

(3)	See Note 7 for discussions relating to both the cashless exercises of warrants in 2009 and the cancellation and reissuance of warrants following down round equity financings.

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2012

Private Placement

Schedule of Shares Purchased by Related Parties

The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
MPM Capital		704,607		704,607	$	1,300,000
Bay City Capital		1,626,016		1,626,016		3,000,000
Aberdare Ventures		406,504		406,504		750,000
Charter Life Sciences		216,802		216,802		400,000
Paul Klingenstein		16,525		16,525		30,488
Nicholas L. Teti, Jr.		10,840		10,840		20,000

Public Offerings

Schedule of Shares Purchased by Related Parties

The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
Bay City Capital		1,700,000		1,700,000	$	2,975,000
Mark B. Knudson, Ph.D.		25,000		25,000		43,750
Greg S. Lea		10,000		10,000		17,500

The shares purchased, together with the proceeds, before expenses to the Company, are shown in the table below:


Beneficial Owner	Shares Purchased		Warrants Purchased		Net Proceeds, before expenses, to the Company
Bay City Capital		840,000		167,999	$	1,386,000

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2012

Future Minimum Lease Payment

The following is a schedule of total future minimum lease payments due as of December 31, 2012:


Years ending December 31:
2013	$	285,656
2014		291,369
2015		221,789

	$	798,814

Quarterly Data (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Information


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2012:
Net loss	$	(5,633	)	$	(4,954	)	$	(5,847	)	$	(7,027	)
Basic and diluted net loss per share	$	(0.15	)	$	(0.13	)	$	(0.14	)	$	(0.17	)
2011:
Net loss	$	(5,086	)	$	(5,557	)	$	(7,298	)	$	(8,056	)
Basic and diluted net loss per share	$	(0.18	)	$	(0.20	)	$	(0.26	)	$	(0.22	)

Formation and Business of the Company - Additional Information (Detail)		1 Months Ended				3 Months Ended								12 Months Ended										120 Months Ended
	Dec. 31, 2002 USD ($)	Apr. 16, 2012 shares	Jan. 14, 2010 shares	Nov. 30, 2007 USD ($) shares	Jan. 31, 2006 SFr / shares shares	Dec. 31, 2012 USD ($) $ / shares shares	Sep. 30, 2012 USD ($)	Jun. 30, 2012 USD ($)	Mar. 31, 2012 USD ($)	Dec. 31, 2011 USD ($) $ / shares shares	Sep. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Dec. 31, 2012 USD ($) $ / shares shares	Dec. 31, 2011 USD ($) $ / shares shares	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Dec. 31, 2007 USD ($)	Dec. 31, 2006 USD ($)	Dec. 31, 2005 USD ($)	Dec. 31, 2004 USD ($)	Dec. 31, 2003 USD ($)	Dec. 31, 2012 USD ($) $ / shares shares
Organization And Description Of Business [Line Items]
Common stock, shares outstanding						41,843,270				36,752,746				41,843,270	36,752,746									41,843,270
Common stock, par value \| $ / shares						$ 0.01				$ 0.01				$ 0.01	$ 0.01									$ 0.01
Stock issued, shares		2,271,705	1,239,717	914,975
Net proceeds from initial public offering \| $				$ 39,100,000
Net income(loss) \| $	$ (603,348)					$ (7,027,000)	$ (5,847,000)	$ (4,954,000)	$ (5,633,000)	$ (8,056,000)	$ (7,298,000)	$ (5,557,000)	$ (5,086,000)	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (31,929,200)	$ (37,874,028)	$ (28,575,348)	$ (17,690,477)	$ (11,215,191)	$ (3,448,752)	$ (1,900,288)	$ (200,041,444)
Alpha Medical, Inc.
Organization And Description Of Business [Line Items]
Ownership percentage of an entity combined to form the Company						100.00%								100.00%										100.00%
Beta Medical, Inc.
Organization And Description Of Business [Line Items]
Ownership percentage of an entity combined to form the Company						100.00%								100.00%										100.00%
EnteroMedics Europe
Organization And Description Of Business [Line Items]
Common stock, shares outstanding					20
Common stock, par value \| SFr / shares					SFr 1,000
Repurchased shares percentage					100.00%
Stock issued, shares					1

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended			120 Months Ended
	Dec. 31, 2008	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Schedule Of Significant Accounting Policies [Line Items]
Long-term debt		$ 10,000,000			$ 10,000,000
Cash equivalents maturity period		90 days
Cash collateral money market		$ 200,000	$ 200,000		200,000
Standby letter of credit amount		200,000
Patent related legal expenses		$ 278,987	$ 271,105	$ 306,181	2,443,269
Reclassification of warrant liability	$ 1,400,000			$ 312,751	$ 2,932,766
Increase in accumulated deficit as a result of change in accounting principle	$ 130,968
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment maturity period		3 months
Property and equipment estimated useful lives		3 years
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment maturity period		1 year
Property and equipment estimated useful lives		7 years
Standby Letters of Credit
Schedule Of Significant Accounting Policies [Line Items]
Stand by letter of credit expiration date		Oct. 01, 2013
Money Market Funds
Schedule Of Significant Accounting Policies [Line Items]
Money market funds preserve the value of investment per share		$ 1.00

Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($)		3 Months Ended								12 Months Ended										120 Months Ended
	Dec. 31, 2002	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Dec. 31, 2003	Dec. 31, 2012
Numerator:
Net loss	$ (603,348)	$ (7,027,000)	$ (5,847,000)	$ (4,954,000)	$ (5,633,000)	$ (8,056,000)	$ (7,298,000)	$ (5,557,000)	$ (5,086,000)	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (31,929,200)	$ (37,874,028)	$ (28,575,348)	$ (17,690,477)	$ (11,215,191)	$ (3,448,752)	$ (1,900,288)	$ (200,041,444)
Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding										39,536,500	30,205,447	8,419,575
Weighted-average unvested common shares subject to repurchase
Denominator for net loss per common share-basic and diluted										39,536,500	30,205,447	8,419,575
Net loss per share-basic and diluted		$ (0.17)	$ (0.14)	$ (0.13)	$ (0.15)	$ (0.22)	$ (0.26)	$ (0.20)	$ (0.18)	$ (0.59)	$ (0.86)	$ (2.06)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1448-109256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e2646-109256

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Potential Shares of Common Stock Not Included in Calculation of Diluted Net Loss per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Options Outstanding
Anti-dilutive Securities
Anti-dilutive as of end of each period	7,835,533	3,470,908	812,515
Warrants to purchase common stock
Anti-dilutive Securities
Anti-dilutive as of end of each period	21,216,447	23,923,301	22,224,718

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 13, 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Short-Term Investment Classified as Available for Sale (Detail) - Fair Value, Inputs, Level 2	Dec. 31, 2011 USD ($)
Schedule Of Short Term Investments And Available For Sale Securities [Line Items]
Short-term investments available for sale	$ 1,005,411
U.S. agency securities
Schedule Of Short Term Investments And Available For Sale Securities [Line Items]
Short-term investments available for sale	$ 1,005,411

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References + Details

Amortized Cost and Fair Value of Short-Term Investments Available for Sale, and Related Gross Unrealized Gains and Losses (Detail)	Dec. 31, 2011 USD ($)
Schedule Of Available For Sale And Trading Securities [Line Items]
Cost	$ 1,004,719
Gross Unrealized Gains	692
Gross Unrealized Losses	0
Fair value	1,005,411
U.S. agency securities
Schedule Of Available For Sale And Trading Securities [Line Items]
Cost	1,004,719
Gross Unrealized Gains	692
Gross Unrealized Losses	0
Fair value	$ 1,005,411

- Definition

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13, 17
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15C
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Section A
-Paragraph 4, 5
-Chapter 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Inventory - Additional Information (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Inventories [Line Items]
Long-term inventory	$ 862,000	$ 228,000

Current Inventory (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Inventories [Line Items]
Raw materials	$ 198,647	$ 376,580
Work-in-process	1,051,286	692,043
Finished goods	21,274
Inventory	$ 1,271,207	$ 1,068,623

Property and Equipment (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Furniture and equipment	$ 2,143,025	$ 1,996,462
Computer hardware and software	489,478	474,236
Leasehold improvements	46,754	32,258
Property and Equipment, Gross	2,679,257	2,502,956
Less accumulated depreciation and amortization	(2,069,585)	(1,872,602)
Property and equipment, net	$ 609,672	$ 630,354

- Definition

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

+ References + Details

Schedule of Accrued Expenses (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Accrued Expenses [Line Items]
Professional service related expenses	$ 2,229,057	$ 4,898,360
Payroll related expenses	1,099,713	1,169,941
Other expenses	344,839	305,069
Accrued expenses	$ 3,673,609	$ 6,373,370

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References + Details

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References + Details

Summary of Notes Payable (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Notes Payable [Line Items]
Growth capital loan dated April 16, 2012 (net discount of $316,028 at December 31, 2012) Growth capital loan dated November 18, 2008 (net discount of $216,711 at December 31, 2011)	$ 9,683,972
Total long-term debt	6,683,972	$ 2,881,161
Growth Capital Loan
Notes Payable [Line Items]
Growth capital loan dated April 16, 2012 (net discount of $316,028 at December 31, 2012) Growth capital loan dated November 18, 2008 (net discount of $216,711 at December 31, 2011)	9,683,972	5,188,323
Less current portion	(3,000,000)	(2,307,162)
Total long-term debt	$ 6,683,972	$ 2,881,161

Summary of Notes Payable (Parenthetical) (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Notes Payable [Line Items]
Notes payable, discounts	$ 316,028	$ 216,711
Growth Capital Loan
Notes Payable [Line Items]
Notes payable, discounts	$ 316,028	$ 216,711

Notes Payable - Additional Information (Detail)	1 Months Ended								12 Months Ended				120 Months Ended
Notes Payable - Additional Information (Detail)	Apr. 30, 2012	Apr. 16, 2012 USD ($) $ / Right shares	Jan. 14, 2010 shares	Oct. 31, 2009 shares	Sep. 30, 2009 shares	Jan. 31, 2009	Nov. 30, 2008 $ / shares	Nov. 30, 2007 shares	Dec. 31, 2012 USD ($) $ / Warrants shares	Dec. 31, 2010 USD ($) $ / Warrants shares	Dec. 31, 2009 USD ($) $ / Warrants shares	Dec. 31, 2003 shares	Dec. 31, 2012 USD ($) $ / Warrants shares	Apr. 23, 2012 USD ($) Installment	Dec. 31, 2011 shares	Sep. 28, 2011 $ / Warrants shares	Mar. 01, 2011 Installment	Dec. 14, 2010 $ / Warrants shares	Sep. 29, 2010 $ / Warrants shares	Jul. 08, 2010 Installment $ / Right shares	Feb. 08, 2010	Jan. 20, 2010 $ / Warrants shares	Oct. 07, 2009 $ / Warrants shares	Oct. 02, 2009 USD ($) $ / Warrants	Sep. 29, 2009 USD ($) $ / Warrants	Jul. 01, 2009	Jun. 30, 2009	Apr. 28, 2009 USD ($) $ / Warrants shares	Feb. 14, 2009 $ / Warrants shares	Dec. 31, 2008 USD ($) shares	Nov. 21, 2008 USD ($)	Nov. 18, 2008 USD ($) $ / Warrants shares	Dec. 31, 2007 shares	Dec. 31, 2006 shares	Dec. 31, 2005 shares
Debt Instrument [Line Items]
Principal amount of loan		$ 10,000,000												$ 10,000,000																		$ 20,000,000
Loan agreement with annual rate																										11.00%	12.00%
Final payment fee percentage																																5.00%
Loan agreement with fixed annual rate														8.00%
Common stock exercise price \| $ / shares							$ 9.51
Exercise price \| $ / Warrants																																9.51
Fair value of warrant liability																														$ 1,500,000
Warrant fair value assumption, volatility rate						79.60%
Warrant fair value assumption, dividend rate						0.00%
Warrant fair value assumption, risk free interest rate						2.24%
Warrant fair value assumption, remaining life						9 years 10 months 17 days
Change in value of warrant liability										$ 158,834			$ (3,840,622)
Cashless exercise of warrants \| shares											159,420
Stock issued, shares \| shares		2,271,705	1,239,717					914,975
Amount used to repay outstanding debt														$ 4,700,000
Repayment of principal amount									$ 333,333
Conditional amount to be placed in restricted account at SVB									$ 7,500,000				$ 7,500,000
Common Stock
Debt Instrument [Line Items]
Stock issued, shares \| shares												19,229
SVB Financial Group
Debt Instrument [Line Items]
Principal amount of loan																															$ 10,000,000
Warrants to purchase common stock
Debt Instrument [Line Items]
Exercise price \| $ / Warrants																1.90		2.19	2.15										6.90			9.51
Issued warrant \| shares																1,760,000		17,020,000	3,394,309										67,773			179,328
Warrants issued, term																5 years																10 years
Fair value of warrant liability																																$ 1,400,000
Warrant fair value assumption, volatility rate							78.90%
Warrant fair value assumption, dividend rate							0.00%
Warrant fair value assumption, risk free interest rate							3.54%
Warrant fair value assumption, remaining life							10 years
Warrants to purchase common stock \| Common Stock
Debt Instrument [Line Items]
Warrants outstanding \| shares									21,216,447	22,224,718	1,332,335		21,216,447		23,923,301															293,178			113,850	28,385	28,385
Horizon Funding
Debt Instrument [Line Items]
Principal amount of loan																												$ 5,000,000
Warrants issued																																55,000
Issued warrant \| shares																												495,000
Horizon Funding \| Warrants to purchase common stock
Debt Instrument [Line Items]
Exercise price \| $ / Warrants										3.90	4.80											3.90	4.80					10.01
Issued warrant \| shares																						26,442	57,152					49,460
Warrants issued, term																												10 years
Fair value of warrant liability										$ 312,751	$ 471,585																	$ 542,144
Warrant fair value assumption, volatility rate	99.10%
Warrant fair value assumption, dividend rate	0.00%										0.00%
Warrant fair value assumption, risk free interest rate	3.00%										3.84%
Warrant fair value assumption, remaining life	10 years
Warrants outstanding \| shares										141,025	114,583
Change in value of warrant liability										$ 158,834	$ 119,904
Horizon Funding \| Warrants to purchase common stock \| Minimum
Debt Instrument [Line Items]
Warrant fair value assumption, volatility rate											103.90%
Warrant fair value assumption, remaining life											8 years 10 months 21 days
Horizon Funding \| Warrants to purchase common stock \| Maximum
Debt Instrument [Line Items]
Warrant fair value assumption, volatility rate											104.80%
Warrant fair value assumption, remaining life											9 years 3 months 29 days
Horizon Funding \| Warrants to purchase common stock \| Fair Value, Inputs, Level 3
Debt Instrument [Line Items]
Warrant fair value assumption, dividend rate										0.00%
Warrant fair value assumption, risk free interest rate										3.38%
Horizon Funding \| Warrants to purchase common stock \| Fair Value, Inputs, Level 3 \| Minimum
Debt Instrument [Line Items]
Warrant fair value assumption, volatility rate										113.25%
Warrant fair value assumption, remaining life										8 years 6 months 4 days
Horizon Funding \| Warrants to purchase common stock \| Fair Value, Inputs, Level 3 \| Maximum
Debt Instrument [Line Items]
Warrant fair value assumption, volatility rate										113.33%
Warrant fair value assumption, remaining life										8 years 11 months 12 days
Silicon Valley Bank
Debt Instrument [Line Items]
Number of installments of repayment of debt \| Installment														30
Exercise price \| $ / Right		2.34
Warrants issued																																1,100,000
Issued warrant \| shares		106,746
Term loans, agreed sum		$ 20,000,000
Time for exercising warrant		10 years
Silicon Valley Bank \| Fourth Amendment
Debt Instrument [Line Items]
Loan agreement with annual rate																	11.00%
Number of installments of repayment of debt \| Installment																	30
Silicon Valley Bank \| Fourth Amendment \| If liquidity ratio is greater than 1.50:1.00 and no Event of Default has occurred
Debt Instrument [Line Items]
Loan agreement with fixed annual rate																	6.25%
Silicon Valley Bank \| First Amendment
Debt Instrument [Line Items]
Loan agreement with annual rate																					11.00%
Loan agreement with fixed annual rate																					10.00%
Silicon Valley Bank \| Second Amendment
Debt Instrument [Line Items]
Loan agreement with annual rate																				10.00%
Loan agreement with fixed annual rate																				11.00%
Number of installments of repayment of debt \| Installment																				30
Silicon Valley Bank \| Warrants to purchase common stock
Debt Instrument [Line Items]
Exercise price \| $ / Warrants																									6.90
Fair value of warrant liability																									$ 4,800,000
Warrant fair value assumption, volatility rate					108.00%
Warrant fair value assumption, dividend rate					0.00%
Warrant fair value assumption, risk free interest rate					3.29%
Warrant fair value assumption, remaining life					9 years 1 month 21 days
Change in value of warrant liability											$ 3,800,000
Cashless exercise of warrants \| shares					159,420
Silicon Valley Bank \| Warrants to purchase common stock \| Second Amendment
Debt Instrument [Line Items]
Exercise price \| $ / Right																				2.10
Issued warrant \| shares																				150,642
Silicon Valley Bank \| Warrants to purchase common stock \| Common Stock
Debt Instrument [Line Items]
Stock issued, shares \| shares					125,470
Western Technology Investment
Debt Instrument [Line Items]
Principal amount of loan																															$ 5,000,000
Warrants issued																																$ 550,000
Western Technology Investment \| Warrants to purchase common stock
Debt Instrument [Line Items]
Exercise price \| $ / Warrants									23.64				23.64											6.90
Fair value of warrant liability																								$ 494,652
Warrant fair value assumption, volatility rate				108.00%
Warrant fair value assumption, dividend rate				0.00%
Warrant fair value assumption, risk free interest rate				3.22%
Warrant fair value assumption, remaining life				9 years 1 month 17 days
Change in value of warrant liability											$ 1,210
Cashless exercise of warrants \| shares				79,710					24,990
Western Technology Investment \| Warrants to purchase common stock \| Common Stock
Debt Instrument [Line Items]
Stock issued, shares \| shares				59,248					2,996

Schedule of Debt Principal Payments (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
2013	$ 3,000,000
2014	4,000,000
2015	3,000,000
Notes payable, gross	10,000,000
Less original issue discount	(316,028)	$ (216,711)
Notes payable, net	$ 9,683,972

Stock Sales - Additional Information (Detail)	1 Months Ended											12 Months Ended
Stock Sales - Additional Information (Detail)	Oct. 31, 2012 USD ($) shares	Apr. 16, 2012 $ / shares shares	Sep. 30, 2011 shares	Sep. 28, 2011 USD ($) $ / shares $ / Warrants shares	Dec. 31, 2010 USD ($) shares	Dec. 14, 2010 USD ($) $ / shares $ / Warrants shares	Sep. 29, 2010 USD ($) $ / shares $ / Warrants shares	Jan. 14, 2010 $ / shares shares	Jan. 31, 2009	Nov. 30, 2008	Nov. 30, 2007 $ / shares shares	Dec. 31, 2012 $ / shares	Dec. 31, 2009 $ / shares	Dec. 31, 2007 $ / shares	Apr. 20, 2012 USD ($)	Jan. 20, 2010 USD ($)	Feb. 14, 2009 $ / Warrants shares	Dec. 31, 2008 USD ($)	Nov. 18, 2008 USD ($) $ / Warrants shares
Class of Stock [Line Items]
Stock issued, shares		2,271,705						1,239,717			914,975
Purchase price per share \| $ / shares		$ 2.223		$ 1.65		$ 1.75		$ 3.90
Gross proceeds before deducting estimated offering expenses \| $				$ 14,500,000		$ 29,800,000	$ 6,300,000								$ 5,000,000	$ 4,800,000
Equity issued, price per share \| $ / shares												$ 2.22	$ 7.28	$ 48
Warrant exercise price \| $ / Warrants																			9.51
Common stock issued upon conversion of convertible preferred stock						3,394,309
Warrant issued, fair value \| $																		$ 1,500,000
Warrant fair value assumption, volatility									79.60%
Warrant fair value assumption, dividend rate									0.00%
Warrant fair value assumption, risk-free interest rate									2.24%
Warrant fair value assumption, remaining life									9 years 10 months 17 days
Maximum Amount of common stock which can be sold under common stock purchase agreement \| $	$ 45,000,000
Maximum Number of Shares of common stock which can be sold under common stock purchase agreement	8,312,122
Period for the sale of common stock	24 months
Pre discounted purchase price \| $ / shares												$ 1.25
Maximum percentage of holding of Common stock at pre discounted price												9.90%
Warrants to purchase common stock
Class of Stock [Line Items]
Warrant issued				1,760,000		17,020,000	3,394,309										67,773		179,328
Equity issued, price per share \| $ / shares							$ 0.125
Warrant exercise price \| $ / Warrants				1.90		2.19	2.15										6.90		9.51
Warrant exercise price as a percentage of original purchase price							125.00%
Warrant issued, term				5 years															10 years
Warrant issued, fair value \| $																			$ 1,400,000
Warrant fair value assumption, volatility										78.90%
Warrant fair value assumption, dividend rate										0.00%
Warrant fair value assumption, risk-free interest rate										3.54%
Warrant fair value assumption, remaining life										10 years
Maximum percentage of common stock holders of warrant allowed to own through exercise of warrants				19.99%
Warrant redemption price \| $ / Warrants				0.01
Number of consecutive trading days				10 days
Required prior notice period				30 days
Warrants to purchase common stock \| Overallotment Option Exercise By Underwriters
Class of Stock [Line Items]
Warrant issued						2,220,000
Underwriter Warrants
Class of Stock [Line Items]
Warrant issued						340,400
Warrant exercise price \| $ / Warrants						2.19
Proceed from issuance of warrant \| $					$ 100
Warrant issued, term						5 years
Warrant issued, fair value \| $						$ 794,869
Warrant fair value assumption, volatility					126.30%
Warrant fair value assumption, dividend rate					0.00%
Warrant fair value assumption, risk-free interest rate					2.08%
Warrant fair value assumption, remaining life					5 years
Minimum
Class of Stock [Line Items]
Discount percentage on issue of shares under common stock purchase agreement	4.00%
Minimum \| Warrants to purchase common stock
Class of Stock [Line Items]
Closing sale price of common stock \| $ / shares				$ 1.00
Maximum
Class of Stock [Line Items]
Discount percentage on issue of shares under common stock purchase agreement	6.80%
Common Stock
Class of Stock [Line Items]
Stock issued, shares			8,800,000	8,800,000	17,020,000	17,020,000
Common Stock \| Overallotment Option Exercise By Underwriters
Class of Stock [Line Items]
Stock issued, shares						2,220,000
Series A Preferred Stock
Class of Stock [Line Items]
Stock issued, shares							3,394,309
Purchase price per share \| $ / shares							$ 1.72
Equity issued, price per share \| $ / shares											$ 6.5593

Convertible Preferred Stock - Additional Information (Detail) - $ / shares	1 Months Ended	12 Months Ended
	Nov. 30, 2007	Dec. 31, 2012	Dec. 31, 2009	Dec. 31, 2007
Common Stock, Preferred Stock, Treasury Stock, Stock-Based Compensation And Other Benefits [Line Items]
Convertible preferred stock authorized		5,000,000
Convertible preferred stock par value		$ 0.01
Equity issued, price per share		$ 2.22	$ 7.28	$ 48
Series A Preferred Stock
Common Stock, Preferred Stock, Treasury Stock, Stock-Based Compensation And Other Benefits [Line Items]
Equity issued, price per share	$ 6.5593
Preferred stock conversion, denominator	4.2379
Series B Preferred Stock
Common Stock, Preferred Stock, Treasury Stock, Stock-Based Compensation And Other Benefits [Line Items]
Equity issued, price per share	3.9430
Preferred stock conversion, denominator	3.9430
Series C Preferred Stock
Common Stock, Preferred Stock, Treasury Stock, Stock-Based Compensation And Other Benefits [Line Items]
Equity issued, price per share	8.0926
Preferred stock conversion, denominator	$ 8.0926

Income Tax - Additional Information (Detail) - USD ($)	12 Months Ended
Income Tax - Additional Information (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
U.S. federal income tax rate	34.00%	34.00%	34.00%
U.S. federal net operating loss carryforwards amount	$ 70,600,000
Net operating loss carryforwards amount available for utilization	22,500,000
Tax benefit recorded to additional paid-in capital	221,000
Gross federal net operating loss carryforward expired amount	48,100,000
Deferred tax asset, write-off of capitalized start-up costs	5,900,000
Deferred tax asset, write-off of capitalized research and development costs	14,200,000
Deferred tax asset, write-off of property and equipment	1,500,000
Deferred tax asset, write-off of research and development credits	$ 2,400,000
Minimum
Income Taxes [Line Items]
Federal net operating loss carryforwards expiration date	2022
Maximum
Income Taxes [Line Items]
Federal net operating loss carryforwards expiration date	2032

Tax Rate reconciliation (Detail)	12 Months Ended
Tax Rate reconciliation (Detail)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Effective Tax Rates Line Items
Computed 'expected' tax benefit	34.00%	34.00%	34.00%
Other permanent adjustments	(2.20%)	(1.80%)	(3.80%)
Research and development credit	0.00%	1.60%	1.20%
Federal valuation allowance	(31.80%)	(33.80%)	(31.40%)
Effective Income Tax Rate, Continuing Operations	0.00%	0.00%	0.00%

Deferred Tax Assets (Detail) - USD ($)	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets (liabilities):
Start-up costs	$ 10,367,000	$ 10,751,000
Capitalized research and development costs	23,658,000	13,201,000
Reserves and accruals	3,447,000	2,299,000
Property and equipment	143,000	23,000
Research and development credit	486,000	462,000
Net operating loss carryforwards	9,185,000	5,127,000
Total gross deferred tax assets	47,286,000	31,863,000
Valuation allowance	(47,286,000)	(31,863,000)
Net deferred tax assets

Stock Option - Additional Information (Detail) - USD ($)	1 Months Ended			12 Months Ended			120 Months Ended
	Sep. 30, 2012	May 31, 2011	Oct. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Schedule Of Stock Options [Line Items]
Stock incentive plan, shares authorized				12,300,000	4,300,000		12,300,000
Stock incentive plan, additional shares authorized	8,000,000	2,000,000	1,149,817
Eligible options			481,288
Tendered eligible options cancelled			481,288
Options granted			384,629
Outstanding Options, Weighted-Average Exercise Price, Options granted			$ 1.90
Percentage of options vested on the date of grant			33.30%
Stock-based compensation				$ 4,225,322	$ 2,892,696	$ 2,564,226	$ 18,688,488
Weighted average estimated fair value of stock options granted				$ 3.19	$ 2.13	$ 0.13
Total unrecognized compensation costs related to non-vested stock options				$ 15,900,000			15,900,000
Total unrecognized compensation costs related to non-vested stock options, weighted-average period of recognition				3 years 2 months 27 days
Aggregate intrinsic value of stock options				$ 3,044	$ 588	$ 12,385
Stock Options Outstanding \| Employee Awards
Schedule Of Stock Options [Line Items]
Award vesting period				4 years
Nonqualified Stock Options
Schedule Of Stock Options [Line Items]
Award vesting period			24 months
Option expiration period			7 years
Nonemployees
Schedule Of Stock Options [Line Items]
Stock-based compensation				$ 52,190	$ 75,614	$ 33,204	$ 1,609,601
Excluding Option Exchange Program
Schedule Of Stock Options [Line Items]
Weighted average estimated fair value of stock options granted						$ 1.97
Minimum
Schedule Of Stock Options [Line Items]
Options granted to participants owning more than 10% of outstanding voting stock, exercise price percentage				110.00%
Option expiration period				5 years
Eligible options, exercise price			$ 6.00
Maximum
Schedule Of Stock Options [Line Items]
Option expiration period				10 years

Summary of Eligible Options Tendered for Cancellation in Exchange Offer (Detail)	1 Months Ended
	Oct. 31, 2010 $ / shares
$6.00 to $9.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of the eligible option, lower limit	$ 6.00
Per share price of the eligible option, upper limit	$ 9.99
The Exchange Ratio of(Eligible Option to New Option)	1.03
$10.00 to $19.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of the eligible option, lower limit	$ 10.00
Per share price of the eligible option, upper limit	$ 19.99
The Exchange Ratio of(Eligible Option to New Option)	1.10
$20.00 to $29.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of the eligible option, lower limit	$ 20.00
Per share price of the eligible option, upper limit	$ 29.99
The Exchange Ratio of(Eligible Option to New Option)	1.20
$30.00 to $39.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of the eligible option, lower limit	$ 30.00
Per share price of the eligible option, upper limit	$ 39.99
The Exchange Ratio of(Eligible Option to New Option)	1.26
$40.00 and up
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of the eligible option, lower limit	$ 40.00
The Exchange Ratio of(Eligible Option to New Option)	1.37

Summary of Stock Option Activity (Detail) - USD ($)	1 Months Ended	12 Months Ended										120 Months Ended
Summary of Stock Option Activity (Detail) - USD ($)	Oct. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Dec. 31, 2003	Dec. 31, 2012
Schedule Of Stock Options [Line Items]
Outstanding Options, Weighted-Average Exercise Price, Options granted	$ 1.90
Outstanding Options, Weighted-Average Exercise Price, Options exercised		$ 1.9	$ 1.9	$ 2.76			$ 3.6	$ 2.76	$ 2.76
Outstanding Options, Number of Shares, Options exercised		(5,219)	(1,139)	(8,586)	(13,450)	(16,829)	(5,854)	(14,504)	(4,927)
Balance, December 31, 2011		$ 1,359,840										$ 1,359,840
Stock Incentive Plan 2003
Schedule Of Stock Options [Line Items]
Shares Available For Grant, Beginning Balance		763,829	1,423,361	99,089	141,998	274,817	58,316	59,907	23,578	7,143
Outstanding Options, Number of Shares, Beginning Balance		3,470,908	812,515	995,562	466,090	350,091	210,260	128,718	56,825
Shares Available For Grant, Shares reserved		8,000,000	2,000,000	1,149,817	500,000		362,183	94,449	113,148	73,260
Shares Available For Grant, Options granted		(4,462,873)	(2,716,464)	(423,789)	(692,645)	(221,838)	(176,098)	(113,277)	(84,028)	(57,466)
Shares Available For Grant, Options exercised
Shares Available For Grant, Options cancelled		93,029	56,932	598,244	149,736	89,019	30,416	17,237	7,209	641
Shares Available For Grant, Ending Balance		4,393,985	763,829	1,423,361	99,089	141,998	274,817	58,316	59,907	23,578	7,143	4,393,985
Outstanding Options, Weighted-Average Exercise Price, Beginning Balance		$ 3.17	$ 5.60	$ 18.96	$ 28.79	$ 19.48	$ 5.00	$ 2.76	$ 2.76
Outstanding Options, Weighted-Average Exercise Price, Shares reserved
Outstanding Options, Number of Shares, Shares reserved
Outstanding Options, Weighted-Average Exercise Price, Options granted		$ 3.35	$ 2.44	$ 1.96	$ 14.68	$ 45.56	$ 45.78	$ 6.90	$ 2.76	$ 2.76
Outstanding Options, Number of Shares, Options granted		4,462,873	2,716,464	423,789	692,645	221,838	176,098	113,277	84,028	57,466
Outstanding Options, Weighted-Average Exercise Price, Options exercised		$ 2.43	$ 1.90	$ 2.76	$ 2.79	$ 3.89	$ 3.65	$ 2.76	$ 2.76
Outstanding Options, Number of Shares, Options exercised		(5,219)	(1,139)	(8,592)	(13,437)	(16,820)	(5,851)	(14,498)	(4,926)
Outstanding Options, Weighted-Average Exercise Price, Options cancelled		$ 2.79	$ 3.21	$ 25.29	$ 31.20	$ 38.69	$ 74.71	$ 2.76	$ 2.76	$ 2.76
Outstanding Options, Number of Shares, Options cancelled		(93,029)	(56,932)	(598,244)	(149,736)	(89,019)	(30,416)	(17,237)	(7,209)	(641)
Outstanding Options, Weighted-Average Exercise Price, Ending Balance		$ 3.28	$ 3.17	$ 5.60	$ 18.96	$ 28.79	$ 19.48	$ 5.00	$ 2.76	$ 2.76		$ 3.28
Outstanding Options, Number of Shares, Ending Balance		7,835,533	3,470,908	812,515	995,562	466,090	350,091	210,260	128,718	56,825		7,835,533
Balance, December 31, 2011		$ 1,359,840										$ 1,359,840
Stock Incentive Plan 2003 \| Inception Date
Schedule Of Stock Options [Line Items]
Shares Available For Grant, Shares reserved												7,143
Outstanding Options, Weighted-Average Exercise Price, Shares reserved
Outstanding Options, Number of Shares, Shares reserved

Options Outstanding Vested and Currently Exercisable by Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2012 USD ($) $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of shares outstanding \| shares	7,835,533
Aggregate Intrinsic Value \| $	$ 1,359,840
Number of Options \| shares	2,288,498
Weighted-Average Exercise Price	$ 3.76
Aggregate Intrinsic Value \| $	$ 664,481
$0.01 to $2.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 0.01
Exercise price, upper limit	$ 2
Number of shares outstanding \| shares	1,038,826
Weighted-Average remaining contractual life (Years)	7 years 4 months 24 days
Aggregate Intrinsic Value \| $	$ 934,943
Number of Options \| shares	550,576
Weighted-Average Exercise Price	$ 1.90
Aggregate Intrinsic Value \| $	$ 495,518
$2.01 to $3.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 2.01
Exercise price, upper limit	$ 3
Number of shares outstanding \| shares	2,265,026
Weighted-Average remaining contractual life (Years)	8 years
Aggregate Intrinsic Value \| $	$ 424,897
Number of Options \| shares	1,009,550
Weighted-Average Exercise Price	$ 2.63
Aggregate Intrinsic Value \| $	$ 168,963
$3.01 to $5.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 3.01
Exercise price, upper limit	$ 5
Number of shares outstanding \| shares	4,413,799
Weighted-Average remaining contractual life (Years)	9 years 7 months 6 days
Number of Options \| shares	610,490
Weighted-Average Exercise Price	$ 3.49
$5.01 to $10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	5.01
Exercise price, upper limit	$ 10
Number of shares outstanding \| shares	4,166
Weighted-Average remaining contractual life (Years)	6 years 1 month 6 days
Number of Options \| shares	4,166
Weighted-Average Exercise Price	$ 8.40
> $10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	0.00
Exercise price, upper limit	$ 10
Number of shares outstanding \| shares	113,716
Weighted-Average remaining contractual life (Years)	5 years 3 months 18 days
Number of Options \| shares	113,716
Weighted-Average Exercise Price	$ 23.99

Stock-Based Compensation for Non employees (Detail)	12 Months Ended
Stock-Based Compensation for Non employees (Detail)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.90%	1.13%	0.89%
Risk-free interest rates, maximum	1.09%	2.68%	2.62%
Expected dividends	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years	5 years 5 months 1 day	4 years
Expected volatility	137.58%	114.80%	113.20%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years 3 months	6 years 3 months	6 years 3 months
Expected volatility	143.98%	124.40%	124.78%
Non Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.24%	0.26%	2.82%
Risk-free interest rates, maximum	2.05%	3.45%	3.81%
Expected dividends	0.00%	0.00%	0.00%
Expected volatility	63.48%	79.50%	113.25%
Expected volatility	142.25%	123.80%	127.93%
Non Employee Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	2 years	2 years 15 days	9 years 4 days
Non Employee Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	9 years 3 months	9 years 11 months 12 days	9 years 10 months 13 days

Estimated Grant-Date Fair Values of Employee Stock Options (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.90%	1.13%	0.89%
Risk-free interest rates, maximum	1.09%	2.68%	2.62%
Expected dividends	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years	5 years 5 months 1 day	4 years
Expected volatility	137.58%	114.80%	113.20%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years 3 months	6 years 3 months	6 years 3 months
Expected volatility	143.98%	124.40%	124.78%

Stock Warrant Activity (Detail) - Warrants to purchase common stock

12 Months Ended

Dec. 31, 2012

$ / Warrants

Dec. 31, 2011

$ / Warrants

Dec. 31, 2010

$ / Warrants

Dec. 31, 2009

$ / Warrants

Dec. 31, 2008

$ / Warrants

Dec. 31, 2007

$ / Warrants

Dec. 31, 2006

$ / Warrants

Dec. 31, 2005

$ / Warrants

Dec. 31, 2004

$ / Warrants

Dec. 31, 2003

$ / Warrants

Common Stock

Class of Warrant or Right [Line Items]

Beginning Balance | shares

23,923,301

22,224,718

1,332,335

293,178

113,850

28,385

Granted | shares

106,746

^[1]

1,759,997

^[1]

21,046,376

^[1],[2]

1,540,036

^[1],[2]

179,328

^[1]

28,385

Exercised | shares

(2,813,600)

(59,219)

(264,120)

^[2]

Cancelled | shares

(2,195)

(153,993)

^[2]

(236,759)

^[2]

Converted upon close of IPO | shares

85,465

Beginning Balance | shares

21,216,447

23,923,301

22,224,718

1,332,335

293,178

113,850

28,385

Beginning Balance | $ / Warrants

^[3]

2.55

2.60

9.44

17.00

28.79

2.76

Granted | $ / Warrants

^[3]

2.34

^[1]

1.90

^[1]

2.19

^[1],[2]

7.86

^[1],[2]

9.51

^[1]

2.76

Exercised | $ / Warrants

^[3]

2.18

2.19

8.49

^[2]

Cancelled | $ / Warrants

^[3]

23.68

5.78

^[2]

9.53

^[2]

Converted upon close of IPO | $ / Warrants

^[3]

37.44

Beginning Balance | $ / Warrants

^[3]

2.60

2.55

2.60

9.44

17.00

28.79

2.76

Series A Preferred Stock

Class of Warrant or Right [Line Items]

Beginning Balance | shares

20,963

Granted | shares

20,963

Exercised | shares

(20,963)

Beginning Balance | shares

20,963

Beginning Balance | $ / Warrants

^[3]

5.46

Granted | $ / Warrants

^[3]

5.46

Exercised | $ / Warrants

^[3]

8.95

Beginning Balance | $ / Warrants

^[3]

5.46

Series B Preferred Stock

Class of Warrant or Right [Line Items]

Beginning Balance | shares

38,210

32,399

20,775

3,916

Granted | shares

5,811

11,624

16,859

3,916

Converted upon close of IPO | shares

(38,210)

Beginning Balance | shares

38,210

32,399

20,775

3,916

Beginning Balance | $ / Warrants

^[3]

23.68

Granted | $ / Warrants

^[3]

23.68

Converted upon close of IPO | $ / Warrants

^[3]

23.68

Beginning Balance | $ / Warrants

^[3]

23.68

Series C Preferred Stock

Class of Warrant or Right [Line Items]

Beginning Balance | shares

24,605

Granted | shares

22,650

24,605

Converted upon close of IPO | shares

(47,255)

Beginning Balance | shares

24,605

Beginning Balance | $ / Warrants

^[3]

48.56

Granted | $ / Warrants

^[3]

48.56

Converted upon close of IPO | $ / Warrants

^[3]

48.56

Beginning Balance | $ / Warrants

^[3]

48.56

[1]	See Notes 7 and 8 for discussions relating to the issuance of warrants in 2012, 2011, 2010, 2009 and 2008.
[2]	See Note 7 for discussions relating to both the cashless exercises of warrants in 2009 and the cancellation and reissuance of warrants following down round equity financings.
[3]	Represents weighted-average exercise price per share.

Warrants - Additional Information (Detail)	Dec. 31, 2012	Dec. 31, 2011
Warrants to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant outstanding, weighted-average remaining contractual life	3 years 3 months 29 days	4 years 3 months 26 days

Related Party Transactions - Additional Information (Detail)	1 Months Ended																12 Months Ended
	Jan. 31, 2013 shares	Dec. 31, 2012 USD ($) $ / shares shares	Dec. 31, 2012 AUD ($) shares	Apr. 16, 2012 $ / shares shares	Sep. 30, 2011 shares	Sep. 28, 2011 $ / shares shares	Jun. 30, 2011 USD ($) $ / shares shares	Dec. 31, 2010 shares	Dec. 14, 2010 $ / shares shares	Oct. 31, 2010 USD ($)	Sep. 29, 2010 $ / shares shares	Aug. 31, 2010 USD ($)	Feb. 28, 2010 USD ($) $ / shares shares	Jan. 14, 2010 $ / shares shares	May 31, 2009 USD ($) $ / shares shares	Nov. 30, 2007 $ / shares shares	Dec. 31, 2012 USD ($) $ / shares shares	Dec. 31, 2012 AUD ($) shares	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 $ / shares	Dec. 31, 2007 $ / shares	Dec. 31, 2005 shares	Dec. 31, 2004 shares	Feb. 14, 2009 shares	Nov. 18, 2008 shares
Related Party Transaction [Line Items]
Stock issued, shares				2,271,705										1,239,717		914,975
Purchase price per share \| $ / shares				$ 2.223		$ 1.65			$ 1.75					$ 3.90
Equity issued, price per share \| $ / shares																	$ 2.22				$ 7.28	$ 48
Award granted, shares																							7,757	3,819
Warrants to purchase common stock
Related Party Transaction [Line Items]
Warrant issued						1,760,000			17,020,000		3,394,309														67,773	179,328
Equity issued, price per share \| $ / shares											$ 0.125
Board of Directors Two
Related Party Transaction [Line Items]
Consulting agreement term															1 year
Consulting fee \| $															$ 275,000
Stock-based compensation \| $																				$ 32,000
Payment for consulting services \| $																				$ 184,000
Option vesting percentage													33.30%
Board of Directors Two \| Monthly Payment
Related Party Transaction [Line Items]
Consulting fee \| $												$ 7,000	$ 15,417
Board of Directors Two \| Hourly
Related Party Transaction [Line Items]
Consulting fee \| $										$ 175
Board of Directors Two \| Stock Options Outstanding
Related Party Transaction [Line Items]
Award granted, shares													12,500
Award granted, price per share \| $ / shares													$ 3.24
Award vesting period													36 months
Board of Directors Two \| Stock Option
Related Party Transaction [Line Items]
Award granted, shares															25,000
Award granted, price per share \| $ / shares															$ 13.80
Award vesting period															36 months
Grant date fair value of award grant \| $															$ 314,000
Board of Directors One
Related Party Transaction [Line Items]
Consulting agreement term							4 years
Consulting fee		$ 12,000	$ 12,000														$ 100,000	$ 96,000
Stock-based compensation \| $																	23,000		$ 10,000
Payment for consulting services \| $																	$ 195,000		$ 67,000
Board of Directors One \| Stock Option
Related Party Transaction [Line Items]
Award granted, shares		75,000	75,000				50,000
Award granted, price per share \| $ / shares		$ 2.65					$ 2.76
Award vesting period							48 months
Grant date fair value of award grant \| $		$ 153,000					$ 108,000
Latest date for approval of Australian reimbursement for the remaining options to vest		Jun. 30, 2014	Jun. 30, 2014														Jun. 30, 2014	Jun. 30, 2014
Board of Directors One \| Stock Option \| Vest on January 22, 2014
Related Party Transaction [Line Items]
Award expected to vest, shares		16,667	16,667														16,667	16,667
Award vesting date		Jan. 22, 2014	Jan. 22, 2014
Board of Directors One \| Stock Option \| Vest on January 22, 2015
Related Party Transaction [Line Items]
Award expected to vest, shares		16,666	16,666														16,666	16,666
Award vesting date		Jan. 22, 2015	Jan. 22, 2015
Board of Directors One \| Stock Option \| Upon approval of fees from the Australian Medical Services Advisory Committee prior to June 30, 2014
Related Party Transaction [Line Items]
Award expected to vest, shares		25,000	25,000														25,000	25,000
Board of Directors One \| Options Vested \| Stock Option
Related Party Transaction [Line Items]
Award vested, shares	16,667
Series A Preferred Stock
Related Party Transaction [Line Items]
Stock issued, shares											3,394,309
Purchase price per share \| $ / shares											$ 1.72
Equity issued, price per share \| $ / shares																$ 6.5593
Common Stock
Related Party Transaction [Line Items]
Stock issued, shares					8,800,000	8,800,000		17,020,000	17,020,000

Shares Purchased by Related Parties (Detail) - USD ($)	1 Months Ended
Shares Purchased by Related Parties (Detail) - USD ($)	Apr. 16, 2012	Sep. 30, 2011	Sep. 28, 2011	Dec. 31, 2010	Dec. 14, 2010	Sep. 29, 2010	Jan. 14, 2010	Nov. 30, 2007	Feb. 14, 2009	Nov. 18, 2008
Related Party Transaction [Line Items]
Shares Purchased	2,271,705						1,239,717	914,975
Common Stock
Related Party Transaction [Line Items]
Shares Purchased		8,800,000	8,800,000	17,020,000	17,020,000
Warrants to purchase common stock
Related Party Transaction [Line Items]
Warrants Purchased			1,760,000		17,020,000	3,394,309			67,773	179,328
Private Placement \| Related Party, One
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 1,300,000
Private Placement \| Related Party, One \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						704,607
Private Placement \| Related Party, Two
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 3,000,000
Private Placement \| Related Party, Two \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						1,626,016
Private Placement \| Related Party, Three
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 750,000
Private Placement \| Related Party, Three \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						406,504
Private Placement \| Related Party, Four
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 400,000
Private Placement \| Related Party, Four \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						216,802
Private Placement \| Related Party, Five
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 30,488
Private Placement \| Related Party, Five \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						16,525
Private Placement \| Related Party, Six
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company						$ 20,000
Private Placement \| Related Party, Six \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased						10,840
Private Placement \| Warrants to purchase common stock \| Related Party, One
Related Party Transaction [Line Items]
Warrants Purchased						704,607
Private Placement \| Warrants to purchase common stock \| Related Party, Two
Related Party Transaction [Line Items]
Warrants Purchased						1,626,016
Private Placement \| Warrants to purchase common stock \| Related Party, Three
Related Party Transaction [Line Items]
Warrants Purchased						406,504
Private Placement \| Warrants to purchase common stock \| Related Party, Four
Related Party Transaction [Line Items]
Warrants Purchased						216,802
Private Placement \| Warrants to purchase common stock \| Related Party, Five
Related Party Transaction [Line Items]
Warrants Purchased						16,525
Private Placement \| Warrants to purchase common stock \| Related Party, Six
Related Party Transaction [Line Items]
Warrants Purchased						10,840
Public Offerings \| Related Party, Two
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company		$ 1,386,000		$ 2,975,000
Public Offerings \| Related Party, Two \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased		840,000		1,700,000
Public Offerings \| Related Party, Seven
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company				$ 43,750
Public Offerings \| Related Party, Seven \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased				25,000
Public Offerings \| Related Party, Eight
Related Party Transaction [Line Items]
Net Proceeds, before expenses, to the Company				$ 17,500
Public Offerings \| Related Party, Eight \| Common Stock
Related Party Transaction [Line Items]
Shares Purchased				10,000
Public Offerings \| Warrants to purchase common stock \| Related Party, Two
Related Party Transaction [Line Items]
Warrants Purchased		167,999		1,700,000
Public Offerings \| Warrants to purchase common stock \| Related Party, Seven
Related Party Transaction [Line Items]
Warrants Purchased				25,000
Public Offerings \| Warrants to purchase common stock \| Related Party, Eight
Related Party Transaction [Line Items]
Warrants Purchased				10,000

Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended									120 Months Ended
	Oct. 31, 2008	Nov. 30, 2007	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Dec. 31, 2012	Mar. 31, 2010
Contingencies And Commitments [Line Items]
Operating lease agreement term	7 years
Operating lease agreement expiration date	Sep. 30, 2015
Total rent expense			$ 270,872	$ 270,872	$ 270,872							$ 1,623,928
Number of months that require patients to be followed out in clinical trials			60 months
Collaborative obesity device research and development agreement, term										5 years
Securities issued, shares										7,757	3,819
Research and development expense			$ 10,668,044	16,673,238	8,498,857							$ 127,449,618
Amendment One
Contingencies And Commitments [Line Items]
Collaborative obesity device research and development agreement, extension period													2 years
Retainer Fees
Contingencies And Commitments [Line Items]
Research and development expense						$ 250,000	$ 250,000	$ 250,000	$ 250,000	$ 250,000
Retainer Fees \| Amendment One
Contingencies And Commitments [Line Items]
Research and development expense				100,000	$ 100,000
Retainer Fees \| Amendment Two
Contingencies And Commitments [Line Items]
Research and development expense				$ 75,000
Collaborative Arrangement
Contingencies And Commitments [Line Items]
Deferred compensation										$ 100,000
Collaborative Arrangement \| Research and development
Contingencies And Commitments [Line Items]
Stock-based compensation		$ 1,700,000
Collaborative Arrangement \| Common Stock
Contingencies And Commitments [Line Items]
Securities issued, shares		34,341								36,630
Minimum
Contingencies And Commitments [Line Items]
Operating lease, monthly base rent	$ 19,570
Maximum
Contingencies And Commitments [Line Items]
Operating lease, monthly base rent	$ 24,643

Future Minimum Payments Under Lease (Detail)	Dec. 31, 2012 USD ($)
Leases Future Minimum Payments [Line Items]
2013	$ 285,656
2014	291,369
2015	221,789
Total	$ 798,814

Quarterly Information (Detail) - USD ($)		3 Months Ended								12 Months Ended										120 Months Ended
Quarterly Information (Detail) - USD ($)	Dec. 31, 2002	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Dec. 31, 2003	Dec. 31, 2012
Quarterly Financial Data [Line Items]
Net loss	$ (603,348)	$ (7,027,000)	$ (5,847,000)	$ (4,954,000)	$ (5,633,000)	$ (8,056,000)	$ (7,298,000)	$ (5,557,000)	$ (5,086,000)	$ (23,460,103)	$ (25,997,322)	$ (17,347,387)	$ (31,929,200)	$ (37,874,028)	$ (28,575,348)	$ (17,690,477)	$ (11,215,191)	$ (3,448,752)	$ (1,900,288)	$ (200,041,444)
Basic and diluted net loss per share		$ (0.17)	$ (0.14)	$ (0.13)	$ (0.15)	$ (0.22)	$ (0.26)	$ (0.20)	$ (0.18)	$ (0.59)	$ (0.86)	$ (2.06)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Subsequent Event - Additional Information (Detail) $ / shares in Units, $ in Millions	1 Months Ended
	Feb. 28, 2013 USD ($) $ / shares $ / Right shares	Apr. 16, 2012 shares	Jan. 14, 2010 shares	Nov. 30, 2007 USD ($) shares	Nov. 18, 2008 $ / Warrants
Subsequent Event [Line Items]
Common stock shares issued, new issues		2,271,705	1,239,717	914,975
Gross proceeds before deducting estimate offering expenses \| $				$ 39.1
Warrants, exercise price \| $ / Warrants					9.51
Public Offering
Subsequent Event [Line Items]
Common stock shares issued, new issues	13,770,000
Warrants issued to purchase common stock	5,508,000
Aggregate share price \| $ / shares	$ 0.95
Gross proceeds before deducting estimate offering expenses \| $	$ 13.1
Warrants, exercise price \| $ / Right	1.14
Warrant, exercise period	5 years
Maximum percentage of ownership restriction on warrant exercises	19.99%

Label	Element	Value
Retained Earnings [Member]
Net Income Loss	us-gaap_NetIncomeLoss	$ (603,348)
Alpha Medical Inc [Member]
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 10,000
Alpha Medical Inc [Member] \| Common Stock [Member]
Stock Issued During Period Shares New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	18,315
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 183
Alpha Medical Inc [Member] \| Additional Paid In Capital [Member]
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	9,817
Beta Medical Inc [Member]
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 10,000
Beta Medical Inc [Member] \| Common Stock [Member]
Stock Issued During Period Shares New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	18,315
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 183
Beta Medical Inc [Member] \| Additional Paid In Capital [Member]
Stock Issued During Period Value New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	9,817
Series Convertible Preferred Stock [Member] \| Alpha Medical Inc [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	301,674
Series Convertible Preferred Stock [Member] \| Alpha Medical Inc [Member] \| Additional Paid In Capital [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	301,619
Series Convertible Preferred Stock [Member] \| Alpha Medical Inc [Member] \| Series A Preferred Stock [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	$ 55
Issuance Of Series Convertible Preferred Stock Upon Merger Shares	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMergerShares	5,525
Series Convertible Preferred Stock [Member] \| Beta Medical Inc [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	$ 301,674
Series Convertible Preferred Stock [Member] \| Beta Medical Inc [Member] \| Additional Paid In Capital [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	301,619
Series Convertible Preferred Stock [Member] \| Beta Medical Inc [Member] \| Series A Preferred Stock [Member]
Issuance Of Series Convertible Preferred Stock Upon Merger	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMerger	$ 55
Issuance Of Series Convertible Preferred Stock Upon Merger Shares	etrm_IssuanceOfSeriesConvertiblePreferredStockUponMergerShares	5,525