View Filing Data

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2013	Jul. 31, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Trading Symbol	ETRM
Entity Registrant Name	EnteroMedics Inc
Entity Central Index Key	0001371217
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		55,618,270

Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 23,087,582	$ 22,308,781
Restricted cash	200,000	200,000
Accounts receivable	17,027	52,406
Inventory	1,358,257	1,271,207
Prepaid expenses and other current assets	607,177	571,654
Total current assets	25,270,043	24,404,048
Property and equipment, net	563,851	609,672
Other assets	1,047,168	1,082,765
Total assets	26,881,062	26,096,485
Current liabilities:
Current portion of notes payable	4,000,000	3,000,000
Accounts payable	227,447	340,555
Accrued expenses	3,500,591	3,673,609
Accrued interest payable	527,383	523,678
Total current liabilities	8,255,421	7,537,842
Notes payable, less current portion (net discounts of $216,327 and $316,028 at June 30, 2013 and December 31, 2012, respectively)	4,783,673	6,683,972
Total liabilities	13,039,094	14,221,814
Commitments and contingencies (Note 4)
Stockholders' equity:
Common stock, $0.01 par value; 125,000,000 shares authorized; 55,618,270 and 41,843,270 shares issued and outstanding at June 30, 2013 and December 31, 2012, respectively	556,183	418,433
Additional paid-in capital	226,362,282	211,628,650
Deficit accumulated during development stage	(213,076,497)	(200,172,412)
Total stockholders' equity	13,841,968	11,874,671
Total liabilities and stockholders' equity	$ 26,881,062	$ 26,096,485

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Notes payable, less current portion, discounts	$ 216,327	$ 316,028
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	55,618,270	41,843,270
Common stock, shares outstanding	55,618,270	41,843,270

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Sales		$ 188,400		$ 311,493	$ 311,493
Cost of goods sold		146,009		231,520	231,520
Gross profit		42,391		79,973	79,973
Operating expenses:
Research and development	$ 2,711,917	2,230,289	$ 5,444,733	4,940,524	132,894,351
Selling, general and administrative	3,359,131	2,541,837	6,945,552	5,355,664	67,075,415
Total operating expenses	6,071,048	4,772,126	12,390,285	10,296,188	199,969,766
Operating loss	(6,071,048)	(4,729,735)	(12,390,285)	(10,216,215)	(199,889,793)
Other income (expense):
Interest income	1,377	2,608	3,583	4,160	4,049,723
Interest expense	(247,599)	(229,289)	(508,653)	(372,894)	(12,973,258)
Change in value of warrant liability					(3,840,622)
Other, net	(5,326)	2,871	(8,730)	(1,597)	(291,579)
Net loss	$ (6,322,596)	$ (4,953,545)	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Net loss per share - basic and diluted	$ (0.11)	$ (0.13)	$ (0.25)	$ (0.28)
Shares used to compute basic and diluted net loss per share	55,618,270	38,667,548	51,281,198	37,712,093

Condensed Consolidated Statements of Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Net loss	$ (6,322,596)	$ (4,953,545)	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Change in unrealized gain (loss) on available for sale investments		(404)		(576)
Comprehensive loss	$ (6,322,596)	$ (4,953,949)	$ (12,904,085)	$ (10,587,122)	$ (212,945,529)

- 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=31042434&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=26872669&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=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

+ Details

Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Cash flows from operating activities:
Net loss	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	81,594	125,608	2,568,622
Loss on sale of equipment		2,443	74,894
Stock-based compensation	2,846,582	1,410,608	21,535,070
Amortization of commitment fees, debt issuance costs and original issue discount	107,318	99,934	4,201,251
Amortization of short-term investment premium or discount		4,071	(300,071)
Change in value of warrant liability			3,840,622
Other, net	43,980		43,980
Change in operating assets and liabilities:
Accounts receivable	(8,601)	(16,933)	(61,007)
Inventory	(87,050)	(19,425)	(1,358,257)
Prepaid expenses and other current assets	(35,523)	170,019	(607,177)
Other assets	27,980	(104,580)	(1,022,416)
Accounts payable	(127,938)	(431,725)	(51,360)
Accrued expenses	(173,018)	(3,232,792)	3,500,591
Accrued interest payable	3,705	59,958	693,205
Net cash used in operating activities	(10,225,056)	(12,519,360)	(179,887,582)
Cash flows from investing activities:
Increase in restricted cash			(200,000)
Purchases of short-term investments available for sale			(19,890,213)
Maturities of short-term investments available for sale			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	(20,943)	(51,803)	(2,928,559)
Net cash used in investing activities	(20,943)	(51,803)	(2,828,488)
Cash flows from financing activities:
Proceeds from stock options exercised			215,684
Proceeds from warrants exercised	9,500	1,407,337	6,463,936
Proceeds from sale of common stock and warrants for purchase of common stock	13,081,500	5,050,000	132,485,939
Common stock financing costs	(1,066,200)	(367,871)	(10,912,501)
Payment to shareholders for fractional shares upon reverse stock split			(355)
Proceeds from sale of Series A, B and C convertible preferred stock			63,766,564
Series A, B and C convertible preferred stock financing costs			(1,658,662)
Proceeds from notes payable and convertible notes payable		5,347,807	47,993,774
Repayments on notes payable	(1,000,000)	(752,841)	(32,178,928)
Debt issuance costs		(50,000)	(371,799)
Net cash provided by financing activities	11,024,800	10,634,432	205,803,652
Net increase (decrease) in cash and cash equivalents	778,801	(1,936,731)	23,087,582
Cash and cash equivalents:
Beginning of period	22,308,781	28,487,688
End of period	23,087,582	26,550,957	23,087,582
Supplemental disclosure:
Interest paid	$ 397,630	213,001	8,070,198
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	4,070,532
Value of warrants issued with sale of common and preferred stock offerings			1,684,832
Cashless exercise of warrants			5,244,778
Conversion of notes and interest payable to Series B and C convertible preferred stock			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			2,932,766
Conversion of convertible preferred stock to common stock			$ 51,132

Summary of Significant Accounting Policies

126 Months Ended

Jun. 30, 2013

Summary of Significant Accounting Policies

(1) Summary of Significant Accounting Policies

Description of Business

EnteroMedics Inc. (formerly Beta Medical, Inc.) (the Company) is developing medical devices using neuroblocking technology to treat obesity, metabolic diseases and other gastrointestinal disorders. The Company was incorporated in the state of Minnesota on December 19, 2002 and was reincorporated in Delaware on July 22, 2004. The Company is in the development stage and since inception 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. In January 2006, the Company established EnteroMedics Europe Sárl, a wholly-owned subsidiary located in Switzerland.

Since inception, the Company has incurred losses through June 30, 2013 totaling $212.9 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 Note 2.

Basis of Presentation

The Company has prepared the accompanying condensed 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.

The accompanying condensed consolidated financial statements and notes thereto are unaudited. In the opinion of the Company’s management, these statements include all adjustments, which are of a normal recurring nature, necessary to present a fair presentation. Interim results are not necessarily indicative of results for a full year. The condensed consolidated balance sheet as of December 31, 2012 was derived from audited consolidated financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The information included in this Form 10-Q should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

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

Fair Value of Financial Instruments

Carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, restricted cash, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximate fair value due to their short maturities. The fair value of the Company’s long-term debt (including the current portion) is approximately $9.1 million as of June 30, 2013 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 condensed consolidated financial statements, long-term debt (including the current portion) would be classified as Level 2 in the fair value hierarchy.

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 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 as of June 30, 2013 and December 31, 2012.

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 note payable agreement (see Note 5), in the event of default, the lender has the right to enforce an account control agreement 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 June 30, 2013 and December 31, 2012. Pursuant to a 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.

Inventory

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

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. The Company’s policy is to classify interest and penalties related to income taxes as income tax expense in the condensed 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. There was no difference from reported net loss for the three and six months ended June 30, 2013. The difference from reported net loss for the three and six months ended June 30, 2012 related entirely to changes in unrealized gains (losses) on available for sale investments.

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.

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 condensed consolidated statements of operations.

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 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 three and six months ended June 30, 2013 and 2012:


	Three months ended June 30,						Six months ended June 30,
	2013			2012			2013			2012
Numerator:
Net loss	$	(6,322,596	)	$	(4,953,545	)	$	(12,904,085	)	$	(10,586,546	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		55,618,270			38,667,548			51,281,198			37,712,093

Net loss per share—basic and diluted	$	(0.11	)	$	(0.13	)	$	(0.25	)	$	(0.28	)

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:


	June 30,
	2013		2012
Stock options outstanding		11,636,494		3,632,544
Warrants to purchase common stock		25,590,555		23,387,377

Recently Issued Accounting Standards

There have been no significant changes in recent accounting pronouncements during the six months ended June 30, 2013 as compared to the recent accounting pronouncements described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

Liquidity and Management's Plans

126 Months Ended

Jun. 30, 2013

Liquidity and Management's Plans

(2) Liquidity and Management’s Plans

The accompanying condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern. For the period from inception (December 19, 2002) through June 30, 2013 the Company experienced net losses of $212.9 million and cash used in operations of $179.9 million. As of June 30, 2013, the Company has not emerged from the development stage and had $23.3 million of cash, cash equivalents and restricted cash. Assuming the Company does not receive any additional funds, it estimates that it has sufficient funds to operate into 2014 (including scheduled or potentially accelerated debt obligations). In order to fund on-going operating cash requirements beyond that point or to further accelerate and execute its business plan, including commercialization of the Maestro Rechargeable System, the Company will need to raise additional funds.

Since inception, the Company has financed its activities principally from the sale of equity securities, debt financing and interest earned on investments. While the Company has been successful in the past in obtaining the necessary capital to support its operations, and has similar future plans, there is no assurance that the Company will be able to obtain additional equity capital or other financing under commercially reasonable terms and conditions, or at all. Furthermore, if the Company issues equity or debt securities to raise additional funds, existing shareholders may experience dilution and the new equity or debt securities it issues may have rights, preferences and privileges senior to those of existing stockholders. In addition, if the Company raises additional funds through collaboration, licensing or other similar arrangements, it may be necessary to relinquish valuable rights to products or proprietary technologies, or grant licenses on terms that are not favorable. If the Company cannot execute its plan to raise funds on acceptable terms, the Company will not be able to continue as a going concern, develop or enhance products, obtain the required regulatory clearances or approvals, execute the Company’s business plan, take advantage of future opportunities, or respond to competitive pressure or unanticipated customer requirements. If the Company is unable to obtain additional financing or the U.S. Food and Drug Administration (FDA) does not approve the Maestro Rechargeable System for commercial use in the U.S., the Company may be required to reduce the scope of, delay, or eliminate some or all of, its planned research, development and commercialization activities, which could materially harm its business. Any of these events would adversely affect the Company’s ability to achieve the Company’s development and commercialization goals, which could have a material adverse effect on the Company’s business, results of operations and financial condition. The Company’s financial statements do not include any adjustments relating to the recoverability or classification of assets or the amounts of liabilities that might result from the outcome of these uncertainties.

Inventory

126 Months Ended

Jun. 30, 2013

Inventory

(3) Inventory

From inception, 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 condensed consolidated balance sheets. There was approximately $906,000 and $862,000 of long-term inventory, primarily consisting of raw materials, as of June 30, 2013 and December 31, 2012, respectively.

Current inventory consists of the following as of:


	June 30, 2013		December 31, 2012
Raw materials	$	192,700	$	198,647
Work-in-process		1,144,283		1,051,286
Finished goods		21,274		21,274

Inventory	$	1,358,257	$	1,271,207

Commitments and Contingencies

126 Months Ended

Jun. 30, 2013

Commitments and Contingencies

(4) Commitments and Contingencies

Operating Lease

The Company rents its office, warehouse and laboratory facilities under an operating lease, which expires on September 30, 2015. Total rent expense recognized for each of the three and six months ended June 30, 2013 and 2012 was $67,718 and $135,436, respectively. At June 30, 2013, future minimum payments under the lease are as follows:


Years ending December 31:
Remaining six months in 2013	$	143,538
2014		291,369
2015		221,789

	$	656,696

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.

Notes Payable

126 Months Ended

Jun. 30, 2013

Notes Payable

(5) Notes Payable

On April 16, 2012, the Company entered into a Loan and Security Agreement (the Loan Agreement) with Silicon Valley Bank (SVB) pursuant to which SVB agreed to make term loans 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 and did not meet certain financial objectives for 2012), on the terms and conditions set forth in the Loan Agreement.

Pursuant to the Loan Agreement, a term loan was funded in the aggregate principal amount of $10.0 million on April 23, 2012. The term loan required 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%. A 5.0% final payment fee 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 was required to comply with certain financial covenants that required 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. The Company did not meet the financial covenants for the period ended March 31, 2013 and therefore entered into a First Amendment (the First Amendment) to the Loan Agreement on May 9, 2013 pursuant to which the Company and SVB agreed to new financial covenants.

The First Amendment eliminated the financial covenants that required 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. It also removed SVB’s ability 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.

The First Amendment added two new financial covenants, one of which requires the Company to receive cumulative aggregate net proceeds of at least $5.0 million by November 15, 2013 and $10.0 million by April 15, 2014 from new capital transactions. The amount required will adjust up or down based on the Company’s actual cash position compared to its financial plan. The second financial covenant requires the Company to maintain a liquidity ratio (unrestricted cash divided by outstanding debt) of at least 1.25:1.00 until it receives FDA approval for the Maestro Rechargeable System at which point it will be reduced to 0.75:1.00. The First Amendment does not change the interest rate or the amortization structure. The Company will pay SVB a $187,000 success fee in the event the Company receives FDA approval for the Maestro Rechargeable System.

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, 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.

Scheduled debt principal payments are as follows as of June 30, 2013:


Years ending December 31:
Remaining six months in 2013	$	2,000,000
2014		4,000,000
2015		3,000,000

		9,000,000
Less: Original issue discount		(216,327	)

Notes payable, net	$	8,783,673

Stock-based Compensation

126 Months Ended

Jun. 30, 2013

Stock-based Compensation

(6) Stock-based Compensation

The fair value method of accounting for share-based payments 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.

Based on the application of these standards, stock-based compensation expense for stock-based awards under the Company’s Amended and Restated 2003 Stock Incentive Plan for the three and six months ended June 30, 2013 and 2012 was allocated to operating expenses and employees and nonemployees as follows:


	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Research and development	$	340,750	$	140,749	$	668,590	$	287,030
Selling, general and administrative		1,160,286		559,376		2,177,992		1,123,578

Total	$	1,501,036	$	700,125	$	2,846,582	$	1,410,608


	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Employees	$	1,429,306	$	681,497	$	2,786,596	$	1,360,942
Nonemployees		71,730		18,628		59,986		49,666

Total	$	1,501,036	$	700,125	$	2,846,582	$	1,410,608

As of June 30, 2013 there was approximately $16.9 million of total unrecognized compensation costs, net of estimated forfeitures, related to employee unvested stock option awards granted after January 1, 2006, which are expected to be recognized over a weighted-average period of 3.13 years.

The estimated grant-date fair values of the stock options were calculated using the Black-Scholes valuation model, based on the following assumptions for the three and six months ended June 30, 2013 and 2012:


	Employees				Employees
	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Risk-free interest rates		0.94%-1.33%		0.99%-1.05%		0.94%-1.33%		0.99%-1.09%
Expected life		6.00-6.25 years		6.00-6.25 years		6.00-6.25 years		6.00-6.25 years
Expected dividends		0%		0%		0%		0%
Expected volatility		148.00%-149.00%		140.98%-141.05%		148.00%-149.00%		123.18%-141.05%


	Nonemployees				Nonemployees
	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Risk-free interest rates		0.36%-1.03%		0.46%-1.31%		0.29%-1.03%		0.24%-2.05%
Expected life		2.01-3.92 years		3.01-9.08 years		2.01-3.92 years		2.00-9.25 years
Expected dividends		0%		0%		0%		0%
Expected volatility		89.00%-124.00%		115.78%-139.80%		82.00%-125.00%		83.05%-139.80%

Option activity under the Company’s Amended and Restated 2003 Stock Incentive Plan for the six months ended June 30, 2013 was as follows:


				Outstanding Options
	Shares Available For Grant			Number of Shares			Weighted- Average Exercise Price
Balance, December 31, 2012		4,393,985			7,835,533		$	3.28
Shares reserved		—			—			—
Options granted		(4,256,000	)		4,256,000			1.33
Options exercised		—			—			—
Options cancelled		455,039			(455,039	)		3.07

Balance, June 30, 2013		593,024			11,636,494			2.57

Stock Sales

126 Months Ended

Jun. 30, 2013

Stock Sales

(7) Stock Sales

Public Offering—February 2013

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.

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 could 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 was not obligated to utilize any portion of the facility and generally remained free to enter into and consummate other equity and debt financing transactions.

On July 31, 2013, the Company terminated the Purchase Agreement with Terrapin. No shares of common stock were sold under the Purchase Agreement.

Subsequent Events

126 Months Ended

Jun. 30, 2013

Subsequent Events

(8) Subsequent Events

On July 31, 2013, the Company entered into an equity distribution agreement with Canaccord Genuity Inc. (Canaccord) to sell shares of the Company’s common stock having aggregate gross sales proceeds of up to $20.0 million, from time to time, through an “at-the-market” (ATM) equity offering program under which Canaccord will act as the Company’s sales agent. The Company will determine, at its sole discretion, the timing and number of shares to be sold under this ATM facility. The Company will pay Canaccord a commission for its services in acting as agent in the sale of common stock equal to 2.0% of the gross sales price per share of all shares sold through it as agent under the equity distribution agreement.

Summary of Significant Accounting Policies (Policies)

126 Months Ended

Jun. 30, 2013

Description of Business

Description of Business

Basis of Presentation

Basis of Presentation

Use of Estimates

Use of Estimates

Principles of Consolidation

Principles of Consolidation

Fair Value of Financial Instruments

Fair Value of Financial Instruments

The Company did not hold any short-term investments as of June 30, 2013 and December 31, 2012.

Cash and Cash Equivalents

Cash and Cash Equivalents

Restricted Cash

Restricted Cash

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 condensed consolidated balance sheets.

Income Taxes

Income Taxes

Comprehensive Loss

Comprehensive Loss

Revenue Recognition

Revenue Recognition

Research and Development Expenses

Research and Development Expenses

Derivative Instruments

Derivative Instruments

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 three and six months ended June 30, 2013 and 2012:


	Three months ended June 30,						Six months ended June 30,
	2013			2012			2013			2012
Numerator:
Net loss	$	(6,322,596	)	$	(4,953,545	)	$	(12,904,085	)	$	(10,586,546	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		55,618,270			38,667,548			51,281,198			37,712,093

Net loss per share—basic and diluted	$	(0.11	)	$	(0.13	)	$	(0.25	)	$	(0.28	)


	June 30,
	2013		2012
Stock options outstanding		11,636,494		3,632,544
Warrants to purchase common stock		25,590,555		23,387,377

Recently Issued Accounting Standards

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

126 Months Ended

Jun. 30, 2013

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 three and six months ended June 30, 2013 and 2012:


	Three months ended June 30,						Six months ended June 30,
	2013			2012			2013			2012
Numerator:
Net loss	$	(6,322,596	)	$	(4,953,545	)	$	(12,904,085	)	$	(10,586,546	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		55,618,270			38,667,548			51,281,198			37,712,093

Net loss per share—basic and diluted	$	(0.11	)	$	(0.13	)	$	(0.25	)	$	(0.28	)

Antidilutive Securities


	June 30,
	2013		2012
Stock options outstanding		11,636,494		3,632,544
Warrants to purchase common stock		25,590,555		23,387,377

Inventory (Tables)

126 Months Ended

Jun. 30, 2013

Current Inventory

Current inventory consists of the following as of:


	June 30, 2013		December 31, 2012
Raw materials	$	192,700	$	198,647
Work-in-process		1,144,283		1,051,286
Finished goods		21,274		21,274

Inventory	$	1,358,257	$	1,271,207

Commitments and Contingencies (Tables)

126 Months Ended

Jun. 30, 2013

Future Minimum Payments under Lease

At June 30, 2013, future minimum payments under the lease are as follows:


Years ending December 31:
Remaining six months in 2013	$	143,538
2014		291,369
2015		221,789

	$	656,696

Notes Payable (Tables)

126 Months Ended

Jun. 30, 2013

Debt Future Payments

Scheduled debt principal payments are as follows as of June 30, 2013:


Years ending December 31:
Remaining six months in 2013	$	2,000,000
2014		4,000,000
2015		3,000,000

		9,000,000
Less: Original issue discount		(216,327	)

Notes payable, net	$	8,783,673

Stock-based Compensation (Tables)

126 Months Ended

Jun. 30, 2013

Summary of Operating Expenses and Employee and Nonemployees


	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Research and development	$	340,750	$	140,749	$	668,590	$	287,030
Selling, general and administrative		1,160,286		559,376		2,177,992		1,123,578

Total	$	1,501,036	$	700,125	$	2,846,582	$	1,410,608


	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Employees	$	1,429,306	$	681,497	$	2,786,596	$	1,360,942
Nonemployees		71,730		18,628		59,986		49,666

Total	$	1,501,036	$	700,125	$	2,846,582	$	1,410,608

Stock Option Valuation Assumptions


	Employees				Employees
	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Risk-free interest rates		0.94%-1.33%		0.99%-1.05%		0.94%-1.33%		0.99%-1.09%
Expected life		6.00-6.25 years		6.00-6.25 years		6.00-6.25 years		6.00-6.25 years
Expected dividends		0%		0%		0%		0%
Expected volatility		148.00%-149.00%		140.98%-141.05%		148.00%-149.00%		123.18%-141.05%


	Nonemployees				Nonemployees
	Three months ended June 30,				Six months ended June 30,
	2013		2012		2013		2012
Risk-free interest rates		0.36%-1.03%		0.46%-1.31%		0.29%-1.03%		0.24%-2.05%
Expected life		2.01-3.92 years		3.01-9.08 years		2.01-3.92 years		2.00-9.25 years
Expected dividends		0%		0%		0%		0%
Expected volatility		89.00%-124.00%		115.78%-139.80%		82.00%-125.00%		83.05%-139.80%

Summary of Stock Option Activity

Option activity under the Company’s Amended and Restated 2003 Stock Incentive Plan for the six months ended June 30, 2013 was as follows:


				Outstanding Options
	Shares Available For Grant			Number of Shares			Weighted- Average Exercise Price
Balance, December 31, 2012		4,393,985			7,835,533		$	3.28
Shares reserved		—			—			—
Options granted		(4,256,000	)		4,256,000			1.33
Options exercised		—			—			—
Options cancelled		455,039			(455,039	)		3.07

Balance, June 30, 2013		593,024			11,636,494			2.57

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012
Schedule Of Significant Accounting Policies [Line Items]
Net income (loss)	$ (6,322,596)	$ (4,953,545)	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Long-term debt	9,100,000		$ 9,100,000		9,100,000
Cash equivalents maturity period			90 days
Cash collateral money market	$ 200,000		$ 200,000		$ 200,000	$ 200,000
Standby letter of credit amount			$ 200,000
Standby letters of credit
Schedule Of Significant Accounting Policies [Line Items]
Stand by letter of credit expiration date			Oct. 01, 2013

- Definition

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

+ References

+ Details

Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($)	3 Months Ended		6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Numerator:
Net loss	$ (6,322,596)	$ (4,953,545)	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding	55,618,270	38,667,548	51,281,198	37,712,093
Net loss per share-basic and diluted	$ (0.11)	$ (0.13)	$ (0.25)	$ (0.28)

- Definition

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

+ References

+ Details

Potential Shares of Common Stock Not Included in Calculation of Diluted Net Loss per Share (Detail) - shares	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Employee Stock Option
Anti-dilutive Securities
Anti-dilutive as of end of each period	11,636,494	3,632,544
Warrants to purchase common stock
Anti-dilutive Securities
Anti-dilutive as of end of each period	25,590,555	23,387,377

Liquidity and Management Plans - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		126 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Liquidity and Managements Plans [Line Items]
Net income (loss)	$ (6,322,596)	$ (4,953,545)	$ (12,904,085)	$ (10,586,546)	$ (212,945,529)
Net cash used in operating activities			(10,225,056)	$ (12,519,360)	(179,887,582)
Cash, cash equivalents and restricted cash	$ 23,300,000		$ 23,300,000		$ 23,300,000

- Definition

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

+ References

+ Details

Inventory - Additional Information (Detail) - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Inventory [Line Items]
Long-term inventory	$ 906,000	$ 862,000

Current Inventory (Detail) - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Inventory [Line Items]
Raw materials	$ 192,700	$ 198,647
Work-in-process	1,144,283	1,051,286
Finished goods	21,274	21,274
Inventory	$ 1,358,257	$ 1,271,207

Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Contingencies And Commitments [Line Items]
Operating lease agreement expiration date			Sep. 30, 2015
Operating lease agreement rent expense	$ 67,718	$ 67,718	$ 135,436	$ 135,436
Number of months that require patients to be followed out in clinical trials			60 months

Future Minimum Payments Under Lease (Detail)	Jun. 30, 2013 USD ($)
Leases Future Minimum Payments [Line Items]
Remaining six months in 2013	$ 143,538
2014	291,369
2015	221,789
Total	$ 656,696

Notes Payable - Additional Information (Detail)	1 Months Ended	6 Months Ended
Notes Payable - Additional Information (Detail)	May 09, 2013 USD ($) BasisPoint	Jun. 30, 2013 USD ($)	Feb. 28, 2013 $ / Right	Apr. 23, 2012 USD ($) Installment	Apr. 16, 2012 USD ($) $ / Right shares
Debt Instrument [Line Items]
Principal amount of loan				$ 10,000,000	$ 10,000,000
Repayment of principal amount		$ 333,333
Loan agreement with fixed annual rate				8.00%
Final payment fee percentage		5.00%
Conditional amount to be placed in restricted account at SVB		$ 7,500,000
Warrant exercise price \| $ / Right			1.14
Silicon Valley Bank
Debt Instrument [Line Items]
Term loans, agreed sum					$ 20,000,000
Number of installments of repayment of debt \| Installment				30
Issued warrant \| shares					106,746
Time for exercising warrant					10 years
Warrant exercise price \| $ / Right					2.34
November 15, 2013 \| Silicon Valley Bank
Debt Instrument [Line Items]
Success fee percentage in the event the Company receives FDA approval for the Maestro Rechargeable System	$ 187,000
November 15, 2013 \| Silicon Valley Bank \| November 15, 2013
Debt Instrument [Line Items]
Cumulative aggregate proceeds from new capital transactions	5,000,000
November 15, 2013 \| Silicon Valley Bank \| November 15, 2014
Debt Instrument [Line Items]
Cumulative aggregate proceeds from new capital transactions	$ 10,000,000
November 15, 2013 \| Silicon Valley Bank \| Until it receives FDA approval for the Maestro Rechargeable System
Debt Instrument [Line Items]
Liquidity ratio (unrestricted cash divided by outstanding debt) \| BasisPoint	1.25
November 15, 2013 \| Silicon Valley Bank \| After FDA approval for the Maestro Rechargeable System
Debt Instrument [Line Items]
Liquidity ratio (unrestricted cash divided by outstanding debt) \| BasisPoint	0.75

Schedule of Debt Principal Payments (Detail) - USD ($)	Jun. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Remaining six months in 2013	$ 2,000,000
2014	4,000,000
2015	3,000,000
Notes payable, gross	9,000,000
Less: Original issue discount	(216,327)	$ (316,028)
Notes payable, net	$ 8,783,673

Stock-Based Compensation Expense for Stock-Based Awards (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross stock-based compensation expense	$ 1,501,036	$ 700,125	$ 2,846,582	$ 1,410,608
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross stock-based compensation expense	340,750	140,749	668,590	287,030
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross stock-based compensation expense	1,160,286	559,376	2,177,992	1,123,578
Employees
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross stock-based compensation expense	1,429,306	681,497	2,786,596	1,360,942
Nonemployees
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Gross stock-based compensation expense	$ 71,730	$ 18,628	$ 59,986	$ 49,666

Stock-Based Compensation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2013 USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total unrecognized compensation costs related to non-vested stock options	$ 16.9
Total unrecognized compensation costs related to non-vested stock options, weighted-average period of recognition	3 years 1 month 17 days

Assumptions for Fair Values of Stock Option (Detail)	3 Months Ended		6 Months Ended
Assumptions for Fair Values of Stock Option (Detail)	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.94%	0.99%	0.94%	0.99%
Risk-free interest rates, maximum	1.33%	1.05%	1.33%	1.09%
Expected dividends	0.00%	0.00%	0.00%	0.00%
Expected volatility, minimum	148.00%	140.98%	148.00%	123.18%
Expected volatility, maximum	149.00%	141.05%	149.00%	141.05%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years	6 years	6 years	6 years
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	6 years 3 months
Non employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.36%	0.46%	0.29%	0.24%
Risk-free interest rates, maximum	1.03%	1.31%	1.03%	2.05%
Expected dividends	0.00%	0.00%	0.00%	0.00%
Expected volatility, minimum	89.00%	115.78%	82.00%	83.05%
Expected volatility, maximum	124.00%	139.80%	125.00%	139.80%
Non employees \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	2 years 4 days	3 years 4 days	2 years 4 days	2 years
Non employees \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	3 years 11 months 1 day	9 years 29 days	3 years 11 months 1 day	9 years 3 months

Stock Option Activity under Amended and Restated Stock Incentive Plan (Detail)	6 Months Ended
	Jun. 30, 2013 $ / shares shares
Shares available for grant
Balance, December 31, 2012	4,393,985
Options granted	(4,256,000)
Options cancelled	455,039
Balance, June 30, 2013	593,024
Outstanding Options, number of shares
Balance, December 31, 2012	7,835,533
Options granted	4,256,000
Options cancelled	(455,039)
Balance, June 30, 2013	11,636,494
Outstanding Options, weighted-average exercise price
Balance, December 31, 2012 \| $ / shares	$ 3.28
Shares reserved \| $ / shares
Options granted \| $ / shares	1.33
Options exercised \| $ / shares
Options cancelled \| $ / shares	3.07
Balance, June 30, 2013 \| $ / shares	$ 2.57

Stock Sales - Additional Information (Detail) $ / shares in Units, $ in Millions	1 Months Ended
	Feb. 28, 2013 USD ($) $ / shares $ / Right shares	Oct. 31, 2012 USD ($) shares
Class of Stock [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%
Maximum Amount of common stock which can be sold under common stock purchase agreement \| $		$ 45.0
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

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2013	Feb. 28, 2013
Subsequent Event [Line Items]
Proceeds from gross sale of common stock		$ 13.1
Subsequent Event
Subsequent Event [Line Items]
Commission or discount percentage on issue of shares	2.00%
Subsequent Event \| Maximum
Subsequent Event [Line Items]
Proceeds from gross sale of common stock	$ 20.0