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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2015	Feb. 29, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
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	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		8,111,763
Entity Public Float			$ 37,854,901

Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 7,927,240	$ 11,619,167
Accounts receivable	57,928	2,812
Inventory	1,686,324	980,519
Prepaid expenses and other current assets	831,495	421,673
Total current assets	10,502,987	13,024,171
Property and equipment, net	326,296	481,522
Other assets	757,802	879,905
Total assets	11,587,085	14,385,598
Current liabilities:
Current portion of notes payable (net of discounts of $23,836 at December 31, 2014)		2,976,164
Current portion of convertible notes payable	717,391
Accounts payable	172,050	399,336
Accrued expenses	3,595,415	3,830,766
Accrued interest payable	1,172	514,937
Total current liabilities	4,486,028	7,721,203
Convertible notes payable, less current portion (net of discounts of $149,340 at December 31, 2015)	549,791
Common stock warrant liability	2,877,817
Total liabilities	7,913,636	7,721,203
Commitments and contingencies (Note 16)
Stockholders' equity:
Common stock, $0.01 par value; 13,333,333 shares authorized; 7,163,820 and 4,638,030 shares issued and outstanding at December 31, 2015 and 2014, respectively	71,638	46,380
Additional paid-in capital	281,182,349	258,699,806
Accumulated deficit	(277,580,538)	(252,081,791)
Total stockholders' equity	3,673,449	6,664,395
Total liabilities and stockholders' equity	$ 11,587,085	$ 14,385,598

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current portion of notes payable, discounts		$ 23,836
Convertible notes payable, less current portion, discounts	$ 149,340
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	13,333,333	13,333,333
Common stock, shares issued	7,163,820	4,638,030
Common stock, shares outstanding	7,163,820	4,638,030

Consolidated Statements of Operations - USD ($)	12 Months Ended
Consolidated Statements of Operations - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Sales	$ 292,000
Cost of goods sold	125,047
Gross profit	166,953
Operating expenses:
Selling, general and administrative	19,892,424	$ 14,561,656	$ 13,658,824
Research and development	8,141,323	11,031,619	11,075,493
Total operating expenses	28,033,747	25,593,275	24,734,317
Operating loss	(27,866,794)	(25,593,275)	(24,734,317)
Other income (expense):
Interest income	1,819	3,331	5,717
Interest expense	(939,182)	(530,222)	(932,364)
Change in value of warrant liability	3,295,536
Other, net	9,874	(8,554)	(119,695)
Net loss	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)
Net loss per share-basic and diluted	$ (4.27)	$ (5.78)	$ (7.03)
Shares used to compute basic and diluted net loss per share	5,970,282	4,524,428	3,667,328

Consolidated Statements of Comprehensive Loss - USD ($)	12 Months Ended
Consolidated Statements of Comprehensive Loss - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net loss	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)
Comprehensive loss	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)

- Definition

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

+ References + Details

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2012	$ 11,874,671	$ 27,896	$ 212,019,187	$ (200,172,412)
Beginning Balance (in shares) at Dec. 31, 2012		2,789,551
Net loss	(25,780,659)			(25,780,659)
Employee stock-based compensation expense	5,788,249		5,788,249
Nonemployee stock-based compensation expense	166,679		166,679
Issuance of common stock in registered public offering	12,015,300	$ 9,180	12,006,120
Issuance of common stock in registered public offering (in shares)		918,000
Stock issued	10,587,117	$ 5,279	10,581,838
Stock issued (Shares)		527,853
Exercise of stock warrants	$ 28,020	$ 14	28,006
Exercise of stock warrants (in shares)	1,353	1,353
Ending Balance (in shares) at Dec. 31, 2013		4,236,757
Ending Balance at Dec. 31, 2013	$ 14,679,377	$ 42,369	240,590,079	(225,953,071)
Net loss	(26,128,720)			(26,128,720)
Employee stock-based compensation expense	6,138,384		6,138,384
Nonemployee stock-based compensation expense	181,323		181,323
Stock issued	9,551,766	$ 3,126	9,548,640
Stock issued (Shares)		312,731
Exercise of stock warrants	$ 2,242,265	$ 885	2,241,380
Exercise of stock warrants (in shares)	88,542	88,542
Ending Balance (in shares) at Dec. 31, 2014	4,638,030	4,638,030
Ending Balance at Dec. 31, 2014	$ 6,664,395	$ 46,380	258,699,806	(252,081,791)
Net loss	(25,498,747)			(25,498,747)
Employee stock-based compensation expense	6,974,489		6,974,489
Nonemployee stock-based compensation expense	(34,712)		(34,712)
Issuance of common stock in registered public offering	9,066,148	$ 21,333	9,044,815
Issuance of common stock in registered public offering (in shares)		2,133,333
Stock issued	6,392,372	$ 3,223	6,389,149
Stock issued (Shares)		322,262
Issuance of common stock for payments made in shares on convertible notes payable	$ 109,504	$ 702	108,802
Issuance of common stock for payments made in shares on senior amortizing convertible notes(Shares)		70,195
Ending Balance (in shares) at Dec. 31, 2015	7,163,820	7,163,820
Ending Balance at Dec. 31, 2015	$ 3,673,449	$ 71,638	$ 281,182,349	$ (277,580,538)

Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Issuance of common stock net of warrants to purchase number of shares of common stock, shares	2,133,316		367,175
Issuance of common stock net of warrants to purchase number of shares of common stock, value	$ 6,003,932
Issuance of common stock in public offering for cash per share	$ 7.50		$ 14.25
Payments of stock issuance costs public offering	$ 929,920		$ 1,066,200
Exercise of stock warrants (in shares)		88,542	1,353
Minimum
Exercise of stock warrants, per share		$ 17.10	$ 17.10
Maximum
Exercise of stock warrants, per share		$ 32.85	$ 28.50
At-The-Market
Payments of stock issuance costs public offering	$ 259,560	$ 284,698	$ 381,981
At-The-Market \| Minimum
Stock issued, per share	$ 16.60	$ 16.54	$ 16.50
At-The-Market \| Maximum
Stock issued, per share	$ 22.70	$ 38.06	$ 31.54

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net loss	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	188,606	188,904	174,629
Loss on sale of equipment	885
Stock-based compensation	6,939,777	6,319,707	5,954,928
Amortization of commitment fees, debt issuance costs and original issue discount	825,735	123,068	199,592
Change in value of warrant liability	(3,295,536)
Other, net			8,030
Change in operating assets and liabilities:
Accounts receivable	(55,116)	14,930	26,634
Inventory	(705,805)	147,422	143,266
Prepaid expenses and other current assets	(409,822)	125,071	24,910
Other assets	349,709	(74,372)	246,764
Accounts payable	(222,636)	267,356	60,732
Accrued expenses	(235,351)	(355,294)	512,451
Accrued interest payable	(487,739)	(11,735)	2,994
Net cash used in operating activities	(22,606,040)	(19,383,663)	(18,425,729)
Cash flows from investing activities:
Decrease in restricted cash			200,000
Purchases of property and equipment	(38,915)	(88,680)	(416,010)
Net cash used in investing activities	(38,915)	(88,680)	(216,010)
Cash flows from financing activities:
Proceeds from warrants exercised		2,242,265	28,020
Proceeds from sale of common stock and warrants for purchase of common stock	22,651,932	9,836,464	24,050,598
Common stock financing costs	(1,721,794)	(284,698)	(1,448,181)
Proceeds from convertible notes payable	1,500,000
Repayments on notes payable	(3,000,000)	(4,000,000)	(3,000,000)
Debt issuance costs	(477,110)
Net cash provided by financing activities	18,953,028	7,794,031	19,630,437
Net (decrease) increase in cash and cash equivalents	(3,691,927)	(11,678,312)	988,698
Cash and cash equivalents:
Beginning of period	11,619,167	23,297,479	22,308,781
End of period	7,927,240	11,619,167	23,297,479
Supplemental disclosure:
Interest paid	601,185	$ 418,889	$ 729,778
Noncash investing and financing activities:
Conversion of convertible notes and interest payable	$ 109,504

Formation and Business of the Company

12 Months Ended

Dec. 31, 2015

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 has devoted substantially all of its resources to recruiting personnel, developing its product technology, obtaining patents to protect its intellectual property, commercialization activities and raising capital and has recently commenced commercial operations in the United States deriving revenues from its primary business activity in 2015. 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.

The Company’s board of directors and stockholders approved a 1-for-15 reverse split (the Reverse Stock Split) of the Company’s outstanding common stock that became effective after trading on January 6, 2016. The Reverse Stock Split did not change the par value of the Company’s stock or the number of preferred shares authorized by the Company’s Fifth Amended and Restated Certificate of Incorporation. An amendment to the Certificate of Incorporation was also approved in connection with the Reverse Stock Split to increase the number of shares of the Company’s common stock authorized for issuance to 150 million shares, effective January 6, 2016. All share and per share amounts have been retroactively adjusted to reflect the Reverse Stock Split for all periods presented.

EnteroMedics has incurred losses through December 31, 2015 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.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

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 and cash equivalents. Cash and cash equivalents 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 and cash equivalents.

The Company’s products require approval from the U.S. Food and Drug Administration (FDA) or corresponding foreign regulatory agencies prior to commercial sales. The Company received FDA approval on January 14, 2015 for vBloc Therapy, delivered via the Maestro Rechargeable System, and has begun a controlled commercial launch at select bariatric centers of excellence in the United States. The Maestro Rechargeable System has also received CE Mark and is listed on the Australian Register of Therapeutic Goods.

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.

The Company’s activities are subject to significant risk and uncertainties, including the ability 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.

Fair Value of Financial Instruments

Carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximate fair value due to their short maturities. The Company’s common stock warrants are required to be reported at fair value and the Company has elected to report its senior amortizing convertible notes at fair value. The fair values of common stock warrants and investments in debt and equity securities, if any, are disclosed in Note 4. The fair value of the Company’s senior amortizing convertible notes is disclosed in Notes 4 and 9.

Common Stock Warrant Liability

Common stock warrants that were issued in connection with the July 8, 2015 public offering and the November 9, 2015 senior amortizing convertible notes are classified as a liability in the consolidated balance sheets, as the common stock warrants issued provide for certain anti-dilution protections in the event shares of common stock or securities convertible into shares of common stock are issued below the then-existing exercise price. The fair value of these common stock warrants is re-measured at each financial reporting period and immediately before exercise, with any changes in fair value being recognized as a component of other income (expense) in the consolidated statements of operations.

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.

Restricted Cash

The Company had $200,000 in a cash collateral money market account as of December 31, 2012. 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 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. The fully secured standby letter of credit was maintained through October 1, 2013, per the terms of the lease agreement.

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 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 five to seven years for furniture and equipment and three to five years for computer hardware and software. 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 or amortization 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, 2015 and 2014 (see Note 12). The Company’s policy is to classify interest and penalties related to income taxes as income tax expense in the consolidated statements of operations.

Medical Device Excise Tax

On January 14, 2015, the Company received FDA approval for vBloc Therapy, delivered via the Maestro Rechargeable System, and starting in the second quarter of 2015 revenues were generated from sales in the United States. As a result, the Company is now required to pay a quarterly Medical Device Tax which is a part of the Affordable Care Act, which imposes a 2.3% excise tax on the sale of certain medical devices by device manufactures, producers or importers. The excise tax was effective on sales of devices made after December 31, 2012. The Company records the Medical Device Tax as an operating expense in the consolidated statements of operations. A moratorium was placed on the Medical Device Tax for 2016 and 2017.

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 years ended December 31, 2015, 2014 and 2013.

Revenue Recognition

Revenue is recognized 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. Products are sold through direct sales or medical device distributors and revenue is recognized upon sale to a bariatric center of excellence or a medical device distributor when 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. A provision for returns is recorded only if product sales provide for a right of

return. No provision for returns was recorded for the year ended December 31, 2015, as the product sales recorded did not provide for rights of return.

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, quality assurance, 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 $202,381, $338,055 and $296,575 for the years ended December 31, 2015, 2014 and 2013, respectively.

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. The Company did not have any such instruments during the years ended December 31, 2015, 2014 and 2013.

Stock-Based Compensation

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. All option grants are expensed on a straight-line basis over the vesting period.

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 years ended December 31, 2015, 2014 and 2013:


	Years ended December 31,
	2015			2014			2013
Numerator:
Net loss	$	(25,498,747	)	$	(26,128,720	)	$	(25,780,659	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		5,970,282			4,524,428			3,667,328

Net loss per share—basic and diluted	$	(4.27	)	$	(5.78	)	$	(7.03	)

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,
	2015		2014		2013
Stock options outstanding		1,535,418		843,563		778,998
Warrants to purchase common stock		3,841,276		1,613,133		1,703,183

Recently Issued Accounting Standards

In April 2015, the Financial Accounting Standards Board (FASB) issued Simplifying the Presentation of Debt Issuance Costs, (Accounting Standards Update No. 2015-03 (ASU 2015-03)), which changes the presentation of debt issuance costs in the financial statements. Under the ASU, an entity presents such costs in the balance sheet as a direct deduction from the recognized debt liability rather than as an asset. Amortization of the costs is reported as interest expense. This guidance will be effective for interim and annual reporting periods beginning after December 15, 2015. The Company has evaluated the impact of adopting ASU 2015-03 and does not believe the new guidance will have a material effect on the Company’s financial position, results of operations or cash flows.

In May 2014, FASB issued Revenue from Contracts with Customers, Topic 606 (Accounting Standards Update No. 2014-09 (ASU 2014-09)), which provides a framework for the recognition of revenue, with the objective that recognized revenues properly reflect amounts an entity is entitled to receive in exchange for goods and services. This guidance will be effective for interim and annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact of adopting ASU 2014-09 on its consolidated financial statements.

Various other accounting standards and interpretations have been issued with 2015 effective dates and effective dates subsequent to December 31, 2015. The Company has evaluated the recently issued accounting pronouncements that are currently effective or will be effective in 2015 and believe that none of them have had or will have a material effect on the Company’s financial position, results of operations or cash flows.

Liquidity and Management's Plans

12 Months Ended

Dec. 31, 2015

Liquidity and Management's Plans

(3)

Liquidity and Management’s Plans

The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern. The Company has financed its operations to date principally through the sale of equity securities, debt financing and interest earned on investments. As of December 31, 2015, the Company had $7.9 million of cash and cash equivalents to fund its anticipated operations through 2016. On November 4, 2015 the Company entered into a securities purchase agreement with institutional investors to issue $25.0 million of senior amortizing convertible notes (the Notes) along with the accompanying warrants. $1.5 million of the Notes was funded at the first closing on November 9, 2015. An additional $11.0 million of the Notes was funded at the second closing on January 11, 2016, with the remaining $12.5 million to be funded at the third closing. Additionally, we have agreed that we will not, for a period of one year after the first closing, issue any further securities, other than certain excluded securities (further described in Note 9). The Company’s anticipated operations include plans that consider the controlled commercial launch of vBloc Therapy, delivered via the Maestro Rechargeable System, which was approved by the FDA on January 14, 2015. The Company believes that it has the flexibility to manage the growth of its expenditures and operations.

Short-term Investments and Fair Value Measurements

12 Months Ended

Dec. 31, 2015

Short-term Investments and Fair Value Measurements

(4)

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 in active markets, 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 may include U.S. treasury securities and money market funds. 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 or held to maturity as of December 31, 2015 and 2014.

The fair value of the Company’s common stock warrant liability is calculated using a Black-Scholes valuation model and is classified as Level 2 in the fair value hierarchy. The common stock warrants issued July 8, 2015 had a fair value of $2,759,583 and $6,003,932 on December 31, 2015 and July 8, 2015, respectively. The common stock warrants issued November 9, 2015 had a fair value of $118,234 and $169,421 on December 31, 2015 and November 9, 2015, respectively. The fair value was calculated using the following assumptions:


	July 2015 Warrants						November 2015 Warrants
	December 31, 2015			July 8, 2015			December 31, 2015			November 9, 2015
Risk-free interest rates		1.31	%		0.91	%		1.76	%		1.75	%
Expected life		36 months			42 months			58 months			60 months
Expected dividends		0	%		0	%		0	%		0	%
Expected volatility		97.94	%		89.89	%		86.27	%		84.85	%

The following table summarizes fair value measurements of the senior amortizing convertible notes and the common stock warrants issued in 2015 by level at December 31, 2015:


	Level 1		Level 2		Level 3		Total
Senior amortizing convertible notes (net of discounts of $149,340)	$	—	$	—	$	1,267,182	$	1,267,182
Common stock warrants		—		2,877,817		—		2,877,817

Total	$	—	$	2,877,817	$	1,267,182	$	4,144,999

As of December 31, 2015 the Company converted $109,504 of senior amortizing convertible notes principal and interest into shares of common stock. There were no gains or losses resulting from the senior amortizing convertible notes recognized in the consolidated statements of operations for the year ended December 31, 2015.

Inventory

12 Months Ended

Dec. 31, 2015

Inventory

(5)

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, 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 $519,000 and $825,000 of long-term inventory, primarily consisting of raw materials, as of December 31, 2015 and 2014, respectively.

Current inventory consists of the following as of:


	December 31,
	2015		2014
Raw materials	$	576,898	$	322,157
Work-in-process		1,066,345		632,615
Finished goods		43,081		25,747

Inventory	$	1,686,324	$	980,519

Property and Equipment

12 Months Ended

Dec. 31, 2015

Property and Equipment

(6)

Property and Equipment

Property and equipment consists of the following as of:


	December 31,
	2015			2014
Furniture and equipment	$	2,299,290		$	2,295,433
Computer hardware and software		585,880			556,556
Leasehold improvements		62,651			62,651

		2,947,821			2,914,640
Less accumulated depreciation and amortization		(2,621,525	)		(2,433,118	)

Property and equipment, net	$	326,296		$	481,522

Accrued Expenses

12 Months Ended

Dec. 31, 2015

Accrued Expenses

(7)

Accrued Expenses

Accrued expenses consist of the following as of:


	December 31,
	2015		2014
Professional service related expenses	$	1,912,775	$	2,107,712
Payroll related expenses		1,270,208		1,267,141
Other expenses		412,432		455,913

Accrued expenses	$	3,595,415	$	3,830,766

Notes Payable

12 Months Ended

Dec. 31, 2015

Notes Payable

(8)

Notes Payable

Notes payable consists of the following as of:


	December 31,
	2015		2014
Growth capital loan dated April 16, 2012 (net of discounts of $0 and $23,836 at December 31, 2015 and 2014, respectively)	$	—	$	2,976,164
Less current portion		—		(2,976,164	)

Total long-term debt	$	—	$	—

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 was 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, a portion of which was used to repay in full outstanding debt of approximately $4.7 million. 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%. The Company 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 Rechargeable System and to implant certain minimum numbers of Maestro Rechargeable Systems during cumulative quarterly measurement periods beginning with the period ended March 31, 2013 and ending with the period ended 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 required 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, both of which were fulfilled. The second financial covenant required the Company to maintain a liquidity ratio (unrestricted cash divided by outstanding debt) of at least 1.25:1.00 until it received FDA approval for the Maestro Rechargeable System on January 14, 2015, at which point it was reduced to 0.75:1.00. The First Amendment did not change the interest rate or the amortization structure. A 5.0% final payment fee of $500,000 was due and paid on September 1, 2015. The Company also paid SVB a $187,000 success fee as a result of receiving FDA approval for the Maestro Rechargeable System.

The Company had 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 had entered into a negative pledge arrangement with SVB pursuant to which it had 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 7,116 shares of common stock, exercisable for ten years from the date of grant, at an exercise price of $35.10 per share.

The final payment related to the Loan Agreement, as amended, was paid on September 1, 2015.

Senior Amortizing Convertible Notes

12 Months Ended

Dec. 31, 2015

Senior Amortizing Convertible Notes

(9)

Senior Amortizing Convertible Notes

On November 4, 2015, the Company entered into a securities purchase agreement (the Purchase Agreement) to issue and sell to four institutional investors 7% senior convertible notes due 2017 that are convertible into shares of the Company’s common stock at a price equal to $4.35 per share with an aggregate principal amount of $25.0 million. Each Note was sold with a warrant to purchase a share of common stock (the Warrants) with an exercise price of $4.65 per share. The Company issued and sold Notes and Warrants for aggregate total proceeds of $12.5 million in two separate closings and will issue and sell Notes and Warrants for aggregate total proceeds of $12.5 million in the third and final closing.

Description of the Notes

The Notes are payable in monthly installments, accrue interest at a rate of 7.0% per annum from the date of issuance and will mature 24 months after the First Closing (defined below), unless converted or redeemed earlier. The Notes may be repaid, at the Company’s election, in either cash or shares of the Company’s common stock at a discount to the then-current market price. The Notes are also convertible from time to time, at the election of the holders, into shares of the Company’s common stock at an initial conversion price of $4.35 per share. The conversion price was adjusted to $1.09 per share on January 29, 2016, the 16^th trading day following the Reverse Stock Split, per the terms of the Notes.

The holder of each Note has the right to convert any portion of such Note unless the holder, together with its affiliates, beneficially owns in excess of 4.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to the conversion, as such percentage ownership is determined in accordance with the terms of the Notes. However, any holder may increase or decrease such percentage to any other percentage, but in no event above 9.99%, provided that any increase of such percentage will not be effective until 61 days after providing notice to the Company.

The Company has determined that the conversion feature in the Notes requires bifurcation and liability classification and measurement, at fair value, and requires evaluation at each reporting period. Under Accounting Standards Codification (ASC) 825, Financial Instruments, the FASB provides an alternative to bifurcation and companies may instead elect fair value measurement for the entire instrument, including the debt and conversion feature. The Company has elected the fair value alternative in order to simplify its accounting and reporting of the Notes upon issuance. The Company has also concluded that the fair value of the Notes at issuance is equal to the gross proceeds received less the fair value of the Warrants issued in conjunction with the Notes. The fair value of the Warrants is recorded as a discount to the Notes and amortized to interest expense following the effective interest rate method over the term of the Notes.

The first of the three closings (the First Closing) occurred on November 9, 2015. At the First Closing, the Company issued and sold Notes with an aggregate principal amount of $1.5 million, along with Warrants exercisable for 117,520 shares. The fair value of the Warrants issued on November 9, 2015 was determined to be $169,000 using a Black-Scholes valuation model and the following assumptions: (1) dividend yield of 0%; (2) expected volatility of 84.85%; (3) weighted average risk –free interest rate of 1.75%; and (4) expected life of 5.0 years.

The second of the three closings (the Second Closing) occurred on January 11, 2016 after the Company received approval of the offering by the Company’s stockholders and the satisfaction of certain customary closing conditions. At the Second Closing, the Company issued and sold Notes with an aggregate principal amount of $11.0 million, along with Warrants exercisable for 861,842 shares. The fair value of the Warrants issued on January 11, 2016 was determined to be $515,000 using a Black-Scholes valuation model and the following assumptions: (1) dividend yield of 0%; (2) expected volatility of 85.90%; (3) weighted average risk –free interest rate of 1.58%; and (4) expected life of 5.0 years.

At the final of the three closings (the Third Closing) the Company will issue and sell Notes with an aggregate principal amount of $12.5 million, along with Warrants exercisable for 979,366 shares.

On December 31, 2015, the fair value of the outstanding Notes was determined to be $1.3 million using a Binomial Lattice model and the following assumptions: (1) dividend yield of 0%; (2) expected volatility of 57.5%; (3) risk-free interest rate of 1.11%; (4) remaining contractual term of 1.86 years; and (5) fair value of the Company’s common stock of $1.95 per share.

The following table summarizes the installment amounts and additional conversions by the holders of the Notes through December 31, 2015:


	Principal		Interest		Total		Common Shares
Installment amount at December 31, 2015	$	65,217	$	23,651	$	88,868		56,967
Holder conversions during the quarter ended December 31, 2015		18,261		2,375		20,636		13,228

	$	83,478	$	26,026	$	109,504		70,195

Description of the Warrants

Each Warrant is exercisable immediately and for a period of 60 months from the date of the issuance of the Warrant. The Warrants entitle the holders of the Warrants to purchase, in aggregate, 1,958,728 shares of the Company’s common stock upon the completion of the Third Closing, subject to certain adjustments. The Warrants are initially exercisable at an exercise price equal to $4.65, subject to adjustment on the eighteen month anniversary of issuance, and certain other adjustments. The exercise price and number of shares of common stock issuable on the exercise of the Warrants is subject to adjustment upon the issuance of any shares of common stock or securities convertible into shares of common stock below the then-existing exercise price, with certain exceptions, and in the event of any stock split, reverse stock split, recapitalization, reorganization or similar transaction. The holder of each Warrant does not have the right to exercise any portion of such Warrant if the holder, together with its affiliates, beneficially owns in excess of 4.99% of the number of shares of the Company’s common stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the Warrants. However, any holder may increase or decrease such percentage to any other percentage, but in no event above 9.99%, provided that any increase of such percentage will not be effective until 61 days after providing notice to the Company.

The exercise price of the Warrants issued November 9, 2015 was reduced to $1.09 per share on January 29, 2016, the 16^th trading day following the Reverse Stock Split, per the terms of the Warrants. The exercise price of the Warrants issued January 11, 2016 remains $4.65 per share per the terms of the Warrants. All of the Warrants issued with the Notes remain subject to adjustment on the eighteen month anniversary of issuance.

Preferred Stock

12 Months Ended

Dec. 31, 2015

Preferred Stock

(10)

Preferred Stock

The Company’s Amended and Restated Certificate of Incorporation currently authorizes 5,000,000 shares of $0.01 par value preferred stock. As of December 31, 2015 and 2014, there were no shares of preferred stock issued or outstanding.

Stock Sales

12 Months Ended

Dec. 31, 2015

Stock Sales

(11)

Stock Sales

Sales Agreement—July 2015

On July 8, 2015, the Company closed a public offering, where it sold 2,133,333 units at an aggregate price of $7.50 per unit, for gross proceeds of $16.0 million before deducting estimated offering expenses of approximately $1.4 million, of which $532,000 was assigned to the warrants issued with each unit sold and was recognized immediately as interest expense in the consolidated statements of operations as the warrants are exercisable upon issuance. Each unit consisted of: (A)(i) one share of common stock or (ii) one pre-funded Series C warrant to purchase one share of common stock at an exercise price equal to $7.50 per share (Series C Warrant); and (B) one Series A warrant to purchase one share of common stock at an exercise price initially equal to $9.00 per share (Series A Warrant). Each purchaser of a unit could elect to receive a Series C Warrant in lieu of a share of common stock. No Series C Warrants were issued.

The Series A Warrants are exercisable for a period of 42 months from the closing date of the public offering. The exercise price and number of shares of common stock issuable on the exercise of the Series A Warrants are subject to adjustment upon the issuance of any shares of common stock or securities convertible into shares of common stock below the then-existing exercise price, with certain exceptions, and in the event of any stock split, reverse stock split, recapitalization, reorganization or similar transaction. The holder of the Series A Warrant does not have the right to exercise any portion of the Series A Warrant if the holder, together with its affiliates, would, subject to certain limited exceptions, beneficially own in excess of 9.99% of the Company’s common stock outstanding immediately after the exercise or 4.99% as may be elected by the purchaser.

The exercise price of the Series A Warrants issued July 8, 2015 was reduced to $2.40 per share on November 9, 2015 as a result of the issuance of the Notes and was further reduced to $1.50 per share on December 31, 2015 and $0.97 per share on January 29, 2016 after the first and second installment payments on the Notes were made.

Sales Agreement—June 2014

On June 13, 2014, the Company entered into a sales agreement with Cowen and Company, LLC (Cowen) to sell shares of the Company’s common stock having aggregate gross sales proceeds of up to $25.0 million, from time to time, through an ATM under which Cowen will act as the Company’s sales agent (the Cowen ATM). The Company will determine, at its sole discretion, the timing and number of shares to be sold under the Cowen ATM. The Company will pay Cowen a commission for its services in acting as agent in the sale of common stock equal to 3.0% of the gross sales price per share of all shares sold through it as agent under the sales agreement. As of December 31, 2015, the Company had sold 367,903 shares under the Cowen ATM at a weighted-average selling price of $20.60 per share for gross proceeds of $7.6 million before deducting offering expenses. There have been no shares sold under the Cowen ATM subsequent to December 31, 2015 through March 28, 2016. The Company is restricted from issuing shares under the Cowen ATM per the terms of the Notes (see Note 9).

Equity Distribution Agreement—July 2013

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 ATM under which Canaccord acted as the Company’s sales agent (the Canaccord ATM). The Company determined, at its sole discretion, the timing and number of shares sold under the Canaccord ATM. The Company paid 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. The equity distribution agreement with Canaccord was terminated effective June 10, 2014. As of the termination date, the Company had sold a total of 794,933 shares under the Canaccord ATM at a weighted-average selling price of $25.01 per share for gross proceeds of $19.9 million before deducting offering expenses.

Public Offering—February 2013

On February 27, 2013, the Company closed a public offering, selling 918,000 shares of common stock, together with warrants to purchase approximately 367,175 shares of common stock at an aggregate price of $14.25 per share and corresponding warrant, for gross proceeds of $13.1 million before deducting offering expenses. Certain directors of the Company participated in the public offering (see Note 15).

The warrants have an exercise price of $17.10 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.

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Taxes

(12)

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:


	2015			2014			2013
Computed ‘expected’ tax benefit		34.0	%		34.0	%		34.0	%
Other permanent adjustments		1.6	%		-2.3	%		-2.3	%
Research and development credit		0.9	%		0.3	%		3.5	%
Federal valuation allowance		-36.5	%		-32.0	%		-35.2	%

		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:


	2015			2014
Deferred tax assets (liabilities):
Start-up costs	$	8,886,000		$	8,739,000
Capitalized research and development costs		29,781,000			30,276,000
Reserves and accruals		8,121,000			6,052,000
Property and equipment		107,000			94,000
Research and development credit		1,972,000			1,636,000
Net operating loss carryforwards		25,695,000			16,656,000

Total gross deferred tax assets		74,562,000			63,453,000
Valuation allowance		(74,562,000	)		(63,453,000	)

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 defined by IRC Section 382. 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, 2015 and 2014.

The Company’s ability to utilize its net operating loss carryforwards and built-in items of deduction, including capitalized start-up costs and research and development costs, may be substantially limited due to ownership changes that may have occurred or that could occur in the future. These ownership changes may limit the amount of net operating loss carryforwards and built-in items of deduction that can be utilized annually to offset future taxable income. In general, an ownership change, as defined in IRC Section 382, results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50% of the outstanding stock of a company by certain stockholders or public groups. During 2011, the Company completed an IRC Section 382 review and the results of the review indicated that ownership changes had occurred. While the Company has not completed an IRC Section 382 review since 2011, it believes that it is likely that additional ownership changes have occurred since then. Since the Company has experienced an ownership change, utilization of carryforward attributes are subject to an annual limitation, which is determined by first multiplying the value of the Company’s common stock at the time of the ownership change by the applicable long-term, tax-exempt rate, and then could be subject to additional adjustments, as required. Any such limitation may result in the expiration of a significant portion of the carryforward attributes before utilization and the permanent loss of built-in items of deduction. Any carryforward attributes that expire prior to utilization or permanent loss of built-in items of deduction as a result of such limitations will be removed from deferred tax assets with a corresponding adjustment to the valuation allowance.

As of December 31, 2015, the Company has generated U.S. federal net operating loss carryforwards of approximately $117.0 million. 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 2035.

As of December 31, 2015 and 2014, 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.

Net operating loss carryforwards of the Company are subject to review and possible adjustment by the taxing authorities. In addition, the Company is subject to U.S. federal examinations for the years 2012 forward. With certain exceptions (e.g. the net operating loss carryforwards), the Company is no longer subject to U.S. federal, state or local examinations by tax authorities for years prior to 2012. There are no U.S. federal tax examinations currently in progress.

The Company’s Minnesota Corporation Franchise Tax returns for tax years ending December 31, 2011 through December 31, 2013, are currently under review.

Stock Options

12 Months Ended

Dec. 31, 2015

Stock Options

(13)

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, 2015 and 2014, according to the Plan 1,320,000 shares 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.

Stock option activity for the Plan 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
Balance, December 31, 2012		293,106			522,225		$	49.16
Shares reserved		—			—			—
Options granted		(289,710	)		289,710			19.85
Options exercised		—			—			—
Options cancelled		32,937			(32,937	)		45.00

Balance, December 31, 2013		36,333			778,998			38.00
Shares reserved		500,000			—			—
Options granted		(83,823	)		83,823			24.45
Options exercised		—			—			—
Options cancelled		19,258			(19,258	)		36.11

Balance, December 31, 2014		471,768			843,563			37.10	$	519,546

Shares reserved		—			—			—
Options granted		(226,631	)		226,631			15.77
Options exercised		—			—			—
Options cancelled		51,442			(51,442	)		27.74

Balance, December 31, 2015		296,579			1,018,752		$	32.83	$	—

On November 2, 2015, the Company announced that Dan W. Gladney would become the Company’s President and Chief Executive Officer (CEO) effective November 16, 2015, and would join the Company on November 2, 2015 as President-Elect and a member of the Board of Directors. In connection with the appointment of Mr. Gladney to the position of President and CEO, on October 28, 2015, Mr. Gladney was also granted an option to purchase 516,666 shares of the Company’s common stock as an inducement grant, with an exercise price of $3.75 per share, the closing price of the Company’s common stock on October 28, 2015. Mr. Gladney’s option will vest as follows: 25% of the shares will vest as of one year from the date of his employment agreement, and the remaining 75% of the shares will then vest in equal 2.0833% installments each month thereafter over the following 36 months.

The options outstanding, vested and currently exercisable for the Plan and the inducement grant by exercise price at December 31, 2015:


	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 $10.00		536,529		9.7	$	—		6,145	$	3.57	$	—
$10.01 to $20.00		450,016		8.2		—		247,800		19.09		—
$20.01 to $30.00		136,713		6.4		—		96,672		27.52		—
$30.01 to $40.00		79,313		5.0		—		79,310		38.80		—
$40.01 to $50.00		57,058		5.4		—		57,058		40.34		—
> $50.00		275,789		6.3		—		251,474		59.06		—

		1,535,418			$	—		738,459	$	37.44	$	—

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, 2015, 2014 and 2013 was calculated using the following assumptions, defined below:


	Years Ended December 31,
	2015	2014	2013
Risk-free interest rates	0.02%–2.10%	0.08%–2.63%	0.26%–2.98%
Expected life	0.08 years–8.51 years	0.50 years–9.51 years	1.50 years–9.76 years
Expected dividends	0%	0%	0%
Expected volatility	37.36%–132.01%	56.54%–139.65%	80.00%–143.00%

Stock-based compensation expense charged to operations on options granted to nonemployees for the years ended December 31, 2015, 2014 and 2013 was $(34,712), $181,323 and $166,679, respectively.

Employee Stock-Based Awards

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, 2015, 2014 and 2013 was $6.09, $21.23 and $18.32 per share, respectively.

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, 2015, 2014 and 2013:


	Years Ended December 31,
	2015	2014	2013
Risk-free interest rates	1.49%–1.80%	1.73%–1.96%	0.94%–1.33%
Expected life	5.50 years–6.25 years	6.00 years–6.25 years	6.00 years–6.25 years
Expected dividends	0%	0%	0%
Expected volatility	83.36%–111.77%	118.64%–120.70%	148.00%–149.00%

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

Volatility. The expected volatility was based on the Company’s historical volatility.

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, 2015 there was approximately $6.1 million of total unrecognized compensation costs, net of estimated forfeitures, related to employee unvested stock option awards, which are expected to be recognized over a weighted-average period of 2.54 years.

There were no stock option exercises for the years ended December 31, 2015, 2014 and 2013.

Warrants

12 Months Ended

Dec. 31, 2015

Warrants

(14)

Warrants

Stock warrant activity is as follows:


	Common Shares			Price(1)
Balance, December 31, 2012		1,414,244		$	36.83
Granted(2)		367,175			17.10
Exercised		(1,353	)		20.68
Cancelled		(76,883	)		137.09

Balance, December 31, 2013		1,703,183			28.07
Granted		—			—
Exercised		(88,542	)		25.32
Cancelled		(1,508	)		728.40

Balance, December 31, 2014		1,613,133			27.56
Granted(2)		2,250,836			1.66
Exercised		—			—
Cancelled		(22,693	)		32.85

Balance, December 31, 2015		3,841,276		$	12.36

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

(2)	See Notes 9 and 11 for discussions relating to the issuance of warrants in 2015 and 2013.

At December 31, 2015 and 2014, the weighted-average remaining contractual life of outstanding warrants was 2.18 and 1.85 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, 2015

Related Party Transactions

(15)

Related Party Transactions

Public Offerings

As discussed in Note 11, on February 27, 2013, the Company closed a public offering, selling 918,000 shares of common stock, together with warrants to purchase approximately 367,175 shares of common stock at an aggregate price of $14.25 per share and corresponding warrant. The following principal stockholder purchased shares of common stock and warrants at a price of $14.25 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		Proceeds, before expenses, to the Company
Anthony Jansz		10,000		4,000	$	142,500

Anthony Jansz is a director of the Company.

Consulting Agreement—Anthony Jansz

The Company entered into a consulting agreement with Anthony Jansz, who is a member of the board of directors, for the period from June 1, 2011 through April 30, 2015. In exchange for consulting services provided, Mr. Jansz was entitled to receive consulting fees and options to purchase 16,663 shares of common stock at a weighted average exercise price of $29.78. Total stock-based compensation expense recorded was approximately $600, $40,000 and $125,000 for the years ended December 31, 2015, 2014 and 2013, respectively. Due to a failure to meet certain performance conditions, 4,998 shares of the options granted to Mr. Jansz did not vest. In addition to the option grants, the Company paid Mr. Jansz approximately $75,000, $196,000 and $154,000 in fees and expenses for consulting services provided during the years ended December 31, 2015, 2014 and 2013, respectively.

Consulting Agreement—Jon Tremmel

Effective August 10, 2015, the Company entered into a one year consulting agreement with Jon Tremmel & Associates, LLC, which is wholly-owned by Jon Tremmel, a member of the board of directors. In exchange for consulting services provided, Mr. Tremmel was entitled to receive consulting fees and an option to purchase 16,666 shares of common stock at $3.45 per share. Total stock-based compensation expense recorded was approximately $13,000 for the year ended December 31, 2015. In addition to the option grant, the Company paid Mr. Tremmel approximately $50,000 in fees and expenses for consulting services provided during the year ended December 31, 2015.

Other

The Company entered into an agreement with an advisory firm to provide various consulting services. The advisory firm is partially owned by a company with whom a member of our board of directors is a partner. The Company recognized $253,000 in selling, general and administrative expense for the year ended December 31, 2014 for consulting services provided by the advisory firm.

- 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 + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies

(16)

Commitments and Contingencies

Operating Lease

The Company rents its office, warehouse and laboratory facilities under an operating lease, which was originally set to expire on September 30, 2015. On August 25, 2015, the Company entered into an amendment extending the term of the operating lease for three years until September 30, 2018, with monthly base rent ranging from $18,925 to $20,345. Total rent expense recognized for the year ended December 31, 2015 was $262,059 and for each of the years ended December 31, 2014 and 2013 it was $270,872. 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, 2015:


Years ending December 31:
2016	$	229,233
2017		237,749
2018		183,103

	$	650,085

Product Liability Claims

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.

Clinical Trials

The Company is evaluating 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.

Mayo Foundation for Medical Education and Research

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.

The Mayo Foundation received an annual $250,000 retainer fee which commenced in 2005 and continued through January 2009.

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 agreement was further amended on February 3, 2013 and on February 3, 2014 with Amendment Nos. 4 and 5, respectively, extending the joint collaboration between the company and a designated group of physicians and researchers at the Mayo Clinic. No other terms were changed by Amendment Nos. 4 or 5.

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.

Retirement Plan

12 Months Ended

Dec. 31, 2015

Retirement Plan

(17)

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, 2015, 2014 and 2013, the Company did not provide any matching of employees’ contributions.

Quarterly Data

12 Months Ended

Dec. 31, 2015

Quarterly Data

(18)

Quarterly Data (unaudited)

The following table represents certain unaudited quarterly information for each of the eight quarters in the period ended December 31, 2015. 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
2015:
Net loss	$	(7,174	)	$	(7,404	)	$	(4,151	)	$	(6,770	)
Basic and diluted net loss per share	$	(1.48	)	$	(1.49	)	$	(0.60	)	$	(0.95	)
2014:
Net loss	$	(6,732	)	$	(7,501	)	$	(5,714	)	$	(6,181	)
Basic and diluted net loss per share	$	(1.54	)	$	(1.66	)	$	(1.24	)	$	(1.34	)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

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

Common Stock Warrant Liability

Common Stock Warrant Liability

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

Medical Device Excise Tax

Medical Device Excise Tax

Comprehensive Loss

Comprehensive Loss

Revenue Recognition

Revenue Recognition

return. No provision for returns was recorded for the year ended December 31, 2015, as the product sales recorded did not provide for rights of return.

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, 2015, 2014 and 2013:


	Years ended December 31,
	2015			2014			2013
Numerator:
Net loss	$	(25,498,747	)	$	(26,128,720	)	$	(25,780,659	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		5,970,282			4,524,428			3,667,328

Net loss per share—basic and diluted	$	(4.27	)	$	(5.78	)	$	(7.03	)


	December 31,
	2015		2014		2013
Stock options outstanding		1,535,418		843,563		778,998
Warrants to purchase common stock		3,841,276		1,613,133		1,703,183

Recently Issued Accounting Standards

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

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, 2015, 2014 and 2013:


	Years ended December 31,
	2015			2014			2013
Numerator:
Net loss	$	(25,498,747	)	$	(26,128,720	)	$	(25,780,659	)

Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding		5,970,282			4,524,428			3,667,328

Net loss per share—basic and diluted	$	(4.27	)	$	(5.78	)	$	(7.03	)

Antidilutive Securities


	December 31,
	2015		2014		2013
Stock options outstanding		1,535,418		843,563		778,998
Warrants to purchase common stock		3,841,276		1,613,133		1,703,183

Short-term Investments and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Series A Warrants Fair Value Calculated Using Black-Scholes Valuation Model

The fair value was calculated using the following assumptions:


	July 2015 Warrants						November 2015 Warrants
	December 31, 2015			July 8, 2015			December 31, 2015			November 9, 2015
Risk-free interest rates		1.31	%		0.91	%		1.76	%		1.75	%
Expected life		36 months			42 months			58 months			60 months
Expected dividends		0	%		0	%		0	%		0	%
Expected volatility		97.94	%		89.89	%		86.27	%		84.85	%

Summary of Fair Value Measurements of Senior Amortizing Convertible Notes and Common Stock Warrants

The following table summarizes fair value measurements of the senior amortizing convertible notes and the common stock warrants issued in 2015 by level at December 31, 2015:


	Level 1		Level 2		Level 3		Total
Senior amortizing convertible notes (net of discounts of $149,340)	$	—	$	—	$	1,267,182	$	1,267,182
Common stock warrants		—		2,877,817		—		2,877,817

Total	$	—	$	2,877,817	$	1,267,182	$	4,144,999

Inventory (Tables)

12 Months Ended

Dec. 31, 2015

Current Inventory

Current inventory consists of the following as of:


	December 31,
	2015		2014
Raw materials	$	576,898	$	322,157
Work-in-process		1,066,345		632,615
Finished goods		43,081		25,747

Inventory	$	1,686,324	$	980,519

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property and Equipment

Property and equipment consists of the following as of:


	December 31,
	2015			2014
Furniture and equipment	$	2,299,290		$	2,295,433
Computer hardware and software		585,880			556,556
Leasehold improvements		62,651			62,651

		2,947,821			2,914,640
Less accumulated depreciation and amortization		(2,621,525	)		(2,433,118	)

Property and equipment, net	$	326,296		$	481,522

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2015

Accrued Expenses

Accrued expenses consist of the following as of:


	December 31,
	2015		2014
Professional service related expenses	$	1,912,775	$	2,107,712
Payroll related expenses		1,270,208		1,267,141
Other expenses		412,432		455,913

Accrued expenses	$	3,595,415	$	3,830,766

Notes Payable (Tables)

12 Months Ended

Dec. 31, 2015

Notes Payable

Notes payable consists of the following as of:


	December 31,
	2015		2014
Growth capital loan dated April 16, 2012 (net of discounts of $0 and $23,836 at December 31, 2015 and 2014, respectively)	$	—	$	2,976,164
Less current portion		—		(2,976,164	)

Total long-term debt	$	—	$	—

Senior Amortizing Convertible Notes (Tables)

12 Months Ended

Dec. 31, 2015

Summary of Installment Amounts and Additional Conversions

The following table summarizes the installment amounts and additional conversions by the holders of the Notes through December 31, 2015:


	Principal		Interest		Total		Common Shares
Installment amount at December 31, 2015	$	65,217	$	23,651	$	88,868		56,967
Holder conversions during the quarter ended December 31, 2015		18,261		2,375		20,636		13,228

	$	83,478	$	26,026	$	109,504		70,195

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

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:


	2015			2014			2013
Computed ‘expected’ tax benefit		34.0	%		34.0	%		34.0	%
Other permanent adjustments		1.6	%		-2.3	%		-2.3	%
Research and development credit		0.9	%		0.3	%		3.5	%
Federal valuation allowance		-36.5	%		-32.0	%		-35.2	%

		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:


	2015			2014
Deferred tax assets (liabilities):
Start-up costs	$	8,886,000		$	8,739,000
Capitalized research and development costs		29,781,000			30,276,000
Reserves and accruals		8,121,000			6,052,000
Property and equipment		107,000			94,000
Research and development credit		1,972,000			1,636,000
Net operating loss carryforwards		25,695,000			16,656,000

Total gross deferred tax assets		74,562,000			63,453,000
Valuation allowance		(74,562,000	)		(63,453,000	)

Net deferred tax assets	$	—		$	—

Stock Options (Tables)

12 Months Ended

Dec. 31, 2015

Summary of Stock Option Activity

Stock option activity for the Plan 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
Balance, December 31, 2012		293,106			522,225		$	49.16
Shares reserved		—			—			—
Options granted		(289,710	)		289,710			19.85
Options exercised		—			—			—
Options cancelled		32,937			(32,937	)		45.00

Balance, December 31, 2013		36,333			778,998			38.00
Shares reserved		500,000			—			—
Options granted		(83,823	)		83,823			24.45
Options exercised		—			—			—
Options cancelled		19,258			(19,258	)		36.11

Balance, December 31, 2014		471,768			843,563			37.10	$	519,546

Shares reserved		—			—			—
Options granted		(226,631	)		226,631			15.77
Options exercised		—			—			—
Options cancelled		51,442			(51,442	)		27.74

Balance, December 31, 2015		296,579			1,018,752		$	32.83	$	—

Options Outstanding Vested and Currently Exercisable by Exercise Price

The options outstanding, vested and currently exercisable for the Plan and the inducement grant by exercise price at December 31, 2015:


	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 $10.00		536,529		9.7	$	—		6,145	$	3.57	$	—
$10.01 to $20.00		450,016		8.2		—		247,800		19.09		—
$20.01 to $30.00		136,713		6.4		—		96,672		27.52		—
$30.01 to $40.00		79,313		5.0		—		79,310		38.80		—
$40.01 to $50.00		57,058		5.4		—		57,058		40.34		—
> $50.00		275,789		6.3		—		251,474		59.06		—

		1,535,418			$	—		738,459	$	37.44	$	—

Nonemployees

Stock Option Valuation Assumptions

The fair value for the years ended December 31, 2015, 2014 and 2013 was calculated using the following assumptions, defined below:


	Years Ended December 31,
	2015	2014	2013
Risk-free interest rates	0.02%–2.10%	0.08%–2.63%	0.26%–2.98%
Expected life	0.08 years–8.51 years	0.50 years–9.51 years	1.50 years–9.76 years
Expected dividends	0%	0%	0%
Expected volatility	37.36%–132.01%	56.54%–139.65%	80.00%–143.00%

Employees Stock Option Plan

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, 2015, 2014 and 2013:


	Years Ended December 31,
	2015	2014	2013
Risk-free interest rates	1.49%–1.80%	1.73%–1.96%	0.94%–1.33%
Expected life	5.50 years–6.25 years	6.00 years–6.25 years	6.00 years–6.25 years
Expected dividends	0%	0%	0%
Expected volatility	83.36%–111.77%	118.64%–120.70%	148.00%–149.00%

Warrants (Tables)

12 Months Ended

Dec. 31, 2015

Stock Warrants Activity

Stock warrant activity is as follows:


	Common Shares			Price(1)
Balance, December 31, 2012		1,414,244		$	36.83
Granted(2)		367,175			17.10
Exercised		(1,353	)		20.68
Cancelled		(76,883	)		137.09

Balance, December 31, 2013		1,703,183			28.07
Granted		—			—
Exercised		(88,542	)		25.32
Cancelled		(1,508	)		728.40

Balance, December 31, 2014		1,613,133			27.56
Granted(2)		2,250,836			1.66
Exercised		—			—
Cancelled		(22,693	)		32.85

Balance, December 31, 2015		3,841,276		$	12.36

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

(2)	See Notes 9 and 11 for discussions relating to the issuance of warrants in 2015 and 2013.

- 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, 2015

Anthony Jansz

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		Proceeds, before expenses, to the Company
Anthony Jansz		10,000		4,000	$	142,500

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Future Minimum Lease Payment

The following is a schedule of total future minimum lease payments due as of December 31, 2015:


Years ending December 31:
2016	$	229,233
2017		237,749
2018		183,103

	$	650,085

Quarterly Data (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Information


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2015:
Net loss	$	(7,174	)	$	(7,404	)	$	(4,151	)	$	(6,770	)
Basic and diluted net loss per share	$	(1.48	)	$	(1.49	)	$	(0.60	)	$	(0.95	)
2014:
Net loss	$	(6,732	)	$	(7,501	)	$	(5,714	)	$	(6,181	)
Basic and diluted net loss per share	$	(1.54	)	$	(1.66	)	$	(1.24	)	$	(1.34	)

Formation and Business of the Company - Additional Information (Detail)	1 Months Ended
	Jan. 31, 2006 SFr / shares shares	Jan. 06, 2016 shares	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares
Organization And Description Of Business [Line Items]
Common stock, shares outstanding			7,163,820	4,638,030
Common stock, par value \| $ / shares			$ 0.01	$ 0.01
Common stock authorized for issuance			13,333,333	13,333,333
Subsequent Event
Organization And Description Of Business [Line Items]
Common stock, reverse split ratio		0.0667
Common stock authorized for issuance		150,000,000
Alpha Medical, Inc.
Organization And Description Of Business [Line Items]
Ownership percentage of an entity combined to form the Company			100.00%
Beta Medical, Inc.
Organization And Description Of Business [Line Items]
Ownership percentage of an entity combined to form the Company			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 (in shares)	1

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Significant Accounting Policies [Line Items]
Cash equivalents maturity period	90 days
Cash collateral money market	$ 200,000
Standby letter of credit amount	$ 200,000
Excise tax rate on medical devices	2.30%
Provision for returns	$ 0
Patent related legal expenses	202,381	$ 338,055	$ 296,575
Derivative instruments outstanding	$ 0	$ 0	$ 0
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment maturity period	3 months
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment maturity period	1 year
Furniture and Fixtures \| Minimum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	5 years
Furniture and Fixtures \| Maximum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	7 years
Computer hardware and software \| Minimum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	3 years
Computer hardware and software \| Maximum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	5 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
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss	$ (6,770,000)	$ (4,151,000)	$ (7,404,000)	$ (7,174,000)	$ (6,181,000)	$ (5,714,000)	$ (7,501,000)	$ (6,732,000)	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)
Denominator for basic and diluted net loss per share:
Weighted-average common shares outstanding									5,970,282	4,524,428	3,667,328
Net loss per share-basic and diluted	$ (0.95)	$ (0.60)	$ (1.49)	$ (1.48)	$ (1.34)	$ (1.24)	$ (1.66)	$ (1.54)	$ (4.27)	$ (5.78)	$ (7.03)

- 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	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Option Outstanding
Anti-dilutive Securities
Anti-dilutive as of end of each period	1,535,418	843,563	778,998
Warrants to purchase common stock
Anti-dilutive Securities
Anti-dilutive as of end of each period	3,841,276	1,613,133	1,703,183

Liquidity and Management's Plans - Additional Information (Detail) - USD ($)	Dec. 31, 2016	Mar. 31, 2016	Jan. 11, 2016	Dec. 31, 2015	Nov. 09, 2015	Nov. 04, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liquidity and Managements Plans [Line Items]
Cash and cash equivalents				$ 7,927,240			$ 11,619,167	$ 23,297,479	$ 22,308,781
Senior Amortizing Convertible Note
Liquidity and Managements Plans [Line Items]
Senior amortizing convertible notes issued					$ 1,500,000	$ 25,000,000
Senior Amortizing Convertible Note \| First closing
Liquidity and Managements Plans [Line Items]
Senior amortizing convertible notes issued					$ 1,500,000
Senior Amortizing Convertible Note \| Second closing \| Subsequent Event
Liquidity and Managements Plans [Line Items]
Senior amortizing convertible notes issued			$ 11,000,000
Senior Amortizing Convertible Note \| Third closing \| Subsequent Event
Liquidity and Managements Plans [Line Items]
Senior amortizing convertible notes issued		$ 12,500,000
Senior Amortizing Convertible Note \| Third closing \| Scenario, Forecast
Liquidity and Managements Plans [Line Items]
Senior amortizing convertible notes issued	$ 12,500,000

Short - term Investment and Fair Value Measurements - Additional Information (Detail) - USD ($)				12 Months Ended
	Dec. 31, 2015	Nov. 09, 2015	Jul. 08, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants		$ 169,000
Senior amortizing convertible notes principal and interest converted into shares of common stock				$ 109,504
Gains (losses) resulting from conversion of senior amortizing convertible notes				0
Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants				$ 2,877,817
Warrants Issued July 8, 2015 \| Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants	$ 2,759,583		$ 6,003,932
Warrants Issued November 9, 2015 \| Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants	$ 118,234	$ 169,421

Series A Warrants Fair Value Calculated Using Black-Scholes Valuation Model (Detail)				12 Months Ended
	Dec. 31, 2015	Nov. 09, 2015	Jul. 08, 2015	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rates	1.11%	1.75%
Expected life	1 year 10 months 10 days	5 years
Expected dividends	0.00%	0.00%
Expected volatility	57.50%	84.85%
Warrants Issued July 8, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rates			0.91%	1.31%
Expected life			42 months	36 months
Expected dividends			0.00%	0.00%
Expected volatility			89.89%	97.94%
Warrants Issued November 9, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rates		1.75%		1.76%
Expected life		60 months		58 months
Expected dividends		0.00%		0.00%
Expected volatility		84.85%		86.27%

Summary of Fair Value Measurements of Senior Amortizing Convertible Notes and Common Stock Warrants (Detail) - USD ($)		12 Months Ended
	Nov. 09, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior amortizing convertible notes (net of discounts of $149,340)		$ 1,267,182
Fair value of warrants	$ 169,000
Total		4,144,999
Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants		2,877,817
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		2,877,817
Level 2 \| Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants		2,877,817
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior amortizing convertible notes (net of discounts of $149,340)		1,267,182
Total		$ 1,267,182

Summary of Fair Value Measurements of Senior Amortizing Convertible Notes and Common Stock Warrants (Parenthetical) (Detail)	Dec. 31, 2015 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior amortizing convertible notes, discounts	$ 149,340

Inventory - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Inventory [Line Items]
Long-term inventory	$ 519,000	$ 825,000

Current Inventory (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Inventory [Line Items]
Raw materials	$ 576,898	$ 322,157
Work-in-process	1,066,345	632,615
Finished goods	43,081	25,747
Inventory	$ 1,686,324	$ 980,519

Property and Equipment (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Furniture and equipment	$ 2,299,290	$ 2,295,433
Computer hardware and software	585,880	556,556
Leasehold improvements	62,651	62,651
Property and Equipment, Gross	2,947,821	2,914,640
Less accumulated depreciation and amortization	(2,621,525)	(2,433,118)
Property and equipment, net	$ 326,296	$ 481,522

Accrued Expenses (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Accrued Expenses [Line Items]
Professional service related expenses	$ 1,912,775	$ 2,107,712
Payroll related expenses	1,270,208	1,267,141
Other expenses	412,432	455,913
Accrued expenses	$ 3,595,415	$ 3,830,766

Notes Payable (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Accounts Payable [Line Items]
Growth capital loan dated April 16, 2012 (net of discounts of $0 and $23,836 at December 31, 2015 and 2014, respectively)		$ 2,976,164
Less current portion		(2,976,164)
Total long-term debt	$ 0	$ 0

Notes Payable (Parenthetical) (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Accounts Payable [Line Items]
Notes payable, discounts	$ 0	$ 23,836

Notes Payable - Additional Information (Detail)				12 Months Ended
Notes Payable - Additional Information (Detail)	May 09, 2013 USD ($)	Apr. 23, 2012 USD ($) Installment	Apr. 16, 2012 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)	Nov. 09, 2015 shares	Feb. 27, 2013 $ / shares
Debt Instrument [Line Items]
Amount used to repay outstanding debt		$ 4,700,000
Repayment of principal amount				$ 333,333
Loan agreement with fixed annual rate		8.00%
Conditional amount to be placed in restricted account at SVB				$ 7,500,000
Issued warrant \| shares					117,520
Exercise price \| $ / shares						$ 17.10
Silicon Valley Bank
Debt Instrument [Line Items]
Term loans, agreed sum			$ 20,000,000
Principal amount of loan		$ 10,000,000	$ 10,000,000
Number of installments of repayment of debt \| Installment		30
Issued warrant \| shares			7,116
Time for exercising warrant			10 years
Exercise price \| $ / shares			$ 35.10
Silicon Valley Bank \| First Amendment
Debt Instrument [Line Items]
Success fee percentage in the event the Company receives FDA approval for the Maestro Rechargeable System	$ 187,000
Final payment fee percentage				5.00%
Final payment fee				$ 500,000
Silicon Valley Bank \| First Amendment \| November 15, 2013
Debt Instrument [Line Items]
Cumulative aggregate proceeds from new capital transactions	5,000,000
Silicon Valley Bank \| First Amendment \| April 15, 2014
Debt Instrument [Line Items]
Cumulative aggregate proceeds from new capital transactions	$ 10,000,000
Silicon Valley Bank \| First Amendment \| Until it received FDA approval for the Maestro Rechargeable System
Debt Instrument [Line Items]
Liquidity ratio (unrestricted cash divided by outstanding debt)	125.00%
Silicon Valley Bank \| First Amendment \| After FDA approval for the Maestro Rechargeable System
Debt Instrument [Line Items]
Liquidity ratio (unrestricted cash divided by outstanding debt)	75.00%

Senior Amortizing Convertible Notes - Additional Information (Detail) - USD ($)					12 Months Ended
	Jan. 11, 2016	Dec. 31, 2015	Nov. 09, 2015	Nov. 04, 2015	Dec. 31, 2016	Mar. 31, 2016	Jan. 29, 2016	Feb. 27, 2013
Debt Instrument [Line Items]
Convertible notes, per share price			$ 4.35
Exercise price								$ 17.10
Convertible notes, interest rate			7.00%
Convertible notes, maturity period			24 months
Issued warrant			117,520
Fair value of warrants			$ 169,000
Expected dividends		0.00%	0.00%
Expected volatility		57.50%	84.85%
Risk-free interest rates		1.11%	1.75%
Expected life		1 year 10 months 10 days	5 years
Fair value of outstanding notes		$ 1,300,000
Common stock per share		$ 1.95						$ 14.25
Warrants issued, exercisable time period			60 months
Subsequent Event
Debt Instrument [Line Items]
Convertible notes, per share price							$ 1.09
Exercise price	$ 4.65						$ 1.09
Minimum
Debt Instrument [Line Items]
Common stock ownership percentage required to exercise warrants			4.99%
Period available for the percentage to be effective			61 days
Maximum
Debt Instrument [Line Items]
Common stock ownership percentage required to exercise warrants			9.99%
Senior Amortizing Convertible Note
Debt Instrument [Line Items]
Senior amortizing convertible notes to be issue			$ 1,500,000	$ 25,000,000
Convertible notes, per share price				$ 4.35
Exercise price				$ 4.65
Proceeds from issuance of debt instrument including warrants				$ 12,500,000
Convertible notes, interest rate				7.00%
Senior convertible notes, maturity year				2017
Senior Amortizing Convertible Note \| Third closing \| Scenario, Forecast
Debt Instrument [Line Items]
Senior amortizing convertible notes to be issue					$ 12,500,000
Proceeds from issuance of debt instrument including warrants					$ 12,500,000
Senior Amortizing Convertible Note \| Subsequent Event \| Second closing
Debt Instrument [Line Items]
Senior amortizing convertible notes to be issue	$ 11,000,000
Issued warrant	861,842
Fair value of warrants	$ 515,000
Expected dividends	0.00%
Expected volatility	85.90%
Risk-free interest rates	1.58%
Expected life	5 years
Senior Amortizing Convertible Note \| Subsequent Event \| Third closing
Debt Instrument [Line Items]
Senior amortizing convertible notes to be issue						$ 12,500,000
Issued warrant						979,366

Summary of Installment Amounts and Additional Conversions (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015
Short-term Debt [Line Items]
Principal		$ 83,478
Interest		26,026
Total		$ 109,504
Common Shares		70,195
Installment amount
Short-term Debt [Line Items]
Principal		$ 65,217
Interest		23,651
Total		$ 88,868
Common Shares		56,967
Holder Conversions
Short-term Debt [Line Items]
Principal	$ 18,261
Interest	2,375
Total	$ 20,636
Common Shares	13,228

Preferred Stock - Additional Information (Detail) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Preferred Stock [Line Items]
Preferred stock, authorized	5,000,000
Preferred stock, par value	$ 0.01
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0

Stock Sales - Additional Information (Detail) - USD ($)						12 Months Ended
Stock Sales - Additional Information (Detail) - USD ($)	Jul. 08, 2015	Jun. 13, 2014	Jun. 10, 2014	Jul. 31, 2013	Feb. 27, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jan. 29, 2016	Jan. 11, 2016	Nov. 09, 2015
Class of Stock [Line Items]
Public offering selling units	2,133,333
Shares issued, price per unit	$ 7.50
Gross proceeds before deducting estimate offering expenses	$ 16,000,000				$ 13,100,000
Offering costs	$ 1,400,000
Exercise price					$ 17.10
Beneficial ownership percentage	9.99%
Warrant issued											117,520
Purchase price per share					$ 14.25	$ 1.95
Warrant, exercise period					5 years
Maximum percentage of ownership restriction on warrant exercises					19.99%
Common Stock
Class of Stock [Line Items]
Stock Issued (in shares)					918,000	322,262	312,731	527,853
Warrants to purchase common stock
Class of Stock [Line Items]
Offering costs	$ 532,000
Warrant issued					367,175
Series C Warrants
Class of Stock [Line Items]
Exercise price	$ 7.50
Warrant issued	0
Series A Warrants
Class of Stock [Line Items]
Exercise price	$ 9.00					$ 1.50					$ 2.40
Warrants exercisable period	42 months
Subsequent Event
Class of Stock [Line Items]
Exercise price									$ 1.09	$ 4.65
Subsequent Event \| Series A Warrants
Class of Stock [Line Items]
Exercise price									$ 0.97
Canaccord Genuity Inc
Class of Stock [Line Items]
Gross proceeds before deducting estimate offering expenses			$ 19,900,000
Commission or discount percentage on issue of shares				2.00%
Number of shares sold			794,933
Agreement termination effective date			Jun. 10, 2014
Cowen and Company LLC
Class of Stock [Line Items]
Gross proceeds before deducting estimate offering expenses						$ 7,600,000
Commission or discount percentage on issue of shares		3.00%
Number of shares sold						367,903
Minimum
Class of Stock [Line Items]
Beneficial ownership percentage	4.99%
Weighted Average \| Canaccord Genuity Inc
Class of Stock [Line Items]
Sale of stock, price per share			$ 25.01
Weighted Average \| Cowen and Company LLC
Class of Stock [Line Items]
Sale of stock, price per share						$ 20.60
Maximum \| Canaccord Genuity Inc
Class of Stock [Line Items]
Gross proceeds before deducting estimate offering expenses				$ 20,000,000
Maximum \| Cowen and Company LLC
Class of Stock [Line Items]
Gross proceeds before deducting estimate offering expenses		$ 25,000,000

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Line Items]
U.S. federal income tax rate	34.00%	34.00%	34.00%
U.S. federal net operating loss carryforwards amount	$ 117,000,000
Tax benefit recorded to additional paid-in capital	221,000
Unrecognized tax	0	$ 0
Interest or penalties charged or accrued related to unrecognized tax benefits	0
Tax examinations	$ 0
Federal examinations for the years	2012
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	2035

Tax Rate Reconciliation (Detail)	12 Months Ended
Tax Rate Reconciliation (Detail)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Effective Income Tax Rate [Line Items]
Computed 'expected' tax benefit	34.00%	34.00%	34.00%
Other permanent adjustments	1.60%	(2.30%)	(2.30%)
Research and development credit	0.90%	0.30%	3.50%
Federal valuation allowance	(36.50%)	(32.00%)	(35.20%)
Effective Income Tax Rate Reconciliation, Percent, Total	0.00%	0.00%	0.00%

Deferred Tax Assets (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets (liabilities):
Start-up costs	$ 8,886,000	$ 8,739,000
Capitalized research and development costs	29,781,000	30,276,000
Reserves and accruals	8,121,000	6,052,000
Property and equipment	107,000	94,000
Research and development credit	1,972,000	1,636,000
Net operating loss carryforwards	25,695,000	16,656,000
Total gross deferred tax assets	74,562,000	63,453,000
Valuation allowance	(74,562,000)	(63,453,000)
Net deferred tax assets	$ 0	$ 0

Stock Options - Additional Information (Detail) - USD ($)		12 Months Ended
	Nov. 02, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Stock Options [Line Items]
Stock incentive plan, shares authorized		1,320,000	1,320,000
Options granted to participants		10.00%
Weighted average estimated fair value of stock options granted		$ 6.09	$ 21.23	$ 18.32
Total unrecognized compensation costs related to non-vested stock options		$ 6,100,000
Total unrecognized compensation costs related to non-vested stock options, weighted-average period of recognition		2 years 6 months 15 days
Aggregate intrinsic value of stock options		$ 0	$ 0	$ 0
President and Chief Executive Officer
Schedule Of Stock Options [Line Items]
Award vesting period	36 months
Award granted, shares	516,666
Award granted, exercise price per share	$ 3.75
Award granted, vesting installment percentage	2.0833%
Vest as of one year from the date of his employment agreement \| President and Chief Executive Officer
Schedule Of Stock Options [Line Items]
Award granted, vesting percentage	25.00%
Vest in equal 2.0833% installments each month thereafter over the following 36 months \| President and Chief Executive Officer
Schedule Of Stock Options [Line Items]
Award granted, vesting percentage	75.00%
Incentive Stock Options
Schedule Of Stock Options [Line Items]
Options granted to participants		10.00%
Employees \| Employee Awards
Schedule Of Stock Options [Line Items]
Award vesting period		4 years
Nonemployees
Schedule Of Stock Options [Line Items]
Stock-based compensation		$ (34,712)	$ 181,323	$ 166,679
Minimum
Schedule Of Stock Options [Line Items]
Options granted to participants owning more than 10% of outstanding voting stock, exercise price percentage		110.00%
Minimum \| Incentive Stock Options
Schedule Of Stock Options [Line Items]
Option expiration period		5 years
Maximum
Schedule Of Stock Options [Line Items]
Option expiration period		10 years

Summary of Stock Option Activity (Detail) - USD ($)	12 Months Ended
Summary of Stock Option Activity (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value	$ 0
Stock Incentive Plan 2003
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available For Grant, Beginning Balance	471,768	36,333	293,106
Shares Available For Grant, Shares reserved		500,000
Shares Available For Grant, Options granted	(226,631)	(83,823)	(289,710)
Shares Available For Grant, Options exercised	0	0	0
Shares Available For Grant, Options cancelled	51,442	19,258	32,937
Shares Available For Grant, Ending Balance	296,579	471,768	36,333
Outstanding Options, Number of Shares, Beginning Balance	843,563	778,998	522,225
Outstanding Options, Number of Shares, Shares reserved	0	0	0
Outstanding Options, Number of Shares, Options granted	226,631	83,823	289,710
Outstanding Options, Number of Shares, Options exercised	0	0	0
Outstanding Options, Number of Shares, Options cancelled	(51,442)	(19,258)	(32,937)
Outstanding Options, Number of Shares, Ending Balance	1,018,752	843,563	778,998
Outstanding Options, Weighted-Average Exercise Price, Beginning Balance	$ 37.10	$ 38.00	$ 49.16
Outstanding Options, Weighted-Average Exercise Price, Shares reserved	0	0	0
Outstanding Options, Weighted-Average Exercise Price, Options granted	15.77	24.45	19.85
Outstanding Options, Weighted-Average Exercise Price, Options exercised	0	0	0
Outstanding Options, Weighted-Average Exercise Price, Options cancelled	27.74	36.11	45.00
Outstanding Options, Weighted-Average Exercise Price, Ending Balance	$ 32.83	$ 37.10	$ 38.00
Aggregate Intrinsic Value		$ 519,546

Options Outstanding Vested and Currently Exercisable by Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of shares outstanding \| shares	1,535,418
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	738,459
Weighted-Average Exercise Price	$ 37.44
Aggregate Intrinsic Value \| $	$ 0
$0.01 to $10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 0.01
Exercise price, upper limit	$ 10.00
Number of shares outstanding \| shares	536,529
Weighted-Average remaining contractual life (Years)	9 years 8 months 12 days
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	6,145
Weighted-Average Exercise Price	$ 3.57
Aggregate Intrinsic Value \| $	$ 0
$10.01 to $20.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 10.01
Exercise price, upper limit	$ 20.00
Number of shares outstanding \| shares	450,016
Weighted-Average remaining contractual life (Years)	8 years 2 months 12 days
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	247,800
Weighted-Average Exercise Price	$ 19.09
Aggregate Intrinsic Value \| $	$ 0
$20.01 to $30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 20.01
Exercise price, upper limit	$ 30.00
Number of shares outstanding \| shares	136,713
Weighted-Average remaining contractual life (Years)	6 years 4 months 24 days
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	96,672
Weighted-Average Exercise Price	$ 27.52
Aggregate Intrinsic Value \| $	$ 0
$30.01 to $40.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 30.01
Exercise price, upper limit	$ 40.00
Number of shares outstanding \| shares	79,313
Weighted-Average remaining contractual life (Years)	5 years
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	79,310
Weighted-Average Exercise Price	$ 38.80
Aggregate Intrinsic Value \| $	$ 0
$40.01 to $50.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 40.01
Exercise price, upper limit	$ 50.00
Number of shares outstanding \| shares	57,058
Weighted-Average remaining contractual life (Years)	5 years 4 months 24 days
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	57,058
Weighted-Average Exercise Price	$ 40.34
Aggregate Intrinsic Value \| $	$ 0
> $50.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 50.00
Number of shares outstanding \| shares	275,789
Weighted-Average remaining contractual life (Years)	6 years 3 months 18 days
Aggregate Intrinsic Value \| $	$ 0
Number of Options \| shares	251,474
Weighted-Average Exercise Price	$ 59.06
Aggregate Intrinsic Value \| $	$ 0

Stock-Based Compensation for Non Employees (Detail) - Nonemployees	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rates, minimum	0.02%	0.08%	0.26%
Risk-free interest rates, maximum	2.10%	2.63%	2.98%
Expected dividends	0.00%	0.00%	0.00%
Expected Volatility, minimum	37.36%	56.54%	80.00%
Expected Volatility, maximum	132.01%	139.65%	143.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	29 days	6 months	1 year 6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	8 years 6 months 4 days	9 years 6 months 4 days	9 years 9 months 4 days

Estimated Grant-Date Fair Values of Employee Stock Options (Detail) - Employees	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.49%	1.73%	0.94%
Risk-free interest rate, maximum	1.80%	1.96%	1.33%
Expected dividends	0.00%	0.00%	0.00%
Expected volatility factor, minimum	83.36%	118.64%	148.00%
Expected volatility factor, maximum	111.77%	120.70%	149.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	5 years 6 months	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

Stock Warrant Activity (Detail) - Common Stock - $ / shares

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Class of Warrant or Right [Line Items]

Beginning Balance

1,613,133

1,703,183

1,414,244

Granted

^[1]

2,250,836

367,175

Exercised

(88,542)

(1,353)

Cancelled

(22,693)

(1,508)

(76,883)

Ending Balance

3,841,276

1,613,133

1,703,183

Beginning Balance

^[2]

$ 27.56

$ 28.07

$ 36.83

Granted

^[1],[2]

1.66

17.10

Exercised

^[2]

25.32

20.68

Cancelled

^[2]

32.85

728.40

137.09

Ending Balance

^[2]

$ 12.36

$ 27.56

$ 28.07

[1]	See Notes 9 and 11 for discussions relating to the issuance of warrants in 2015 and 2013.
[2]	Represents weighted-average exercise price per share.

Warrants - Additional Information (Detail)	12 Months Ended
Warrants - Additional Information (Detail)	Dec. 31, 2015	Dec. 31, 2014
Warrants to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant outstanding, weighted-average remaining contractual life	2 years 2 months 5 days	1 year 10 months 6 days

Related Party Transactions - Additional Information (Detail) - USD ($)		12 Months Ended
	Feb. 27, 2013	Dec. 31, 2015	Aug. 10, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 09, 2015
Related Party Transaction [Line Items]
Warrant issued						117,520
Purchase price per share	$ 14.25	$ 1.95
Selling,general and administrative expenses		$ 19,892,424		$ 14,561,656	$ 13,658,824
Consulting Agreement - Anthony Jansz
Related Party Transaction [Line Items]
Consulting agreement beginning date		Jun. 01, 2011
Consulting agreement termination date		Apr. 30, 2015
Award granted, shares		16,663
Award granted, price per share		$ 29.78
Stock-based compensation		$ 600		40,000	125,000
Options granted not vest		4,998
Payment for consulting services		$ 75,000		196,000	$ 154,000
Consulting Services
Related Party Transaction [Line Items]
Selling,general and administrative expenses				$ 253,000
Consulting Agreement - Jon Tremmel
Related Party Transaction [Line Items]
Award granted, shares			16,666
Award granted, price per share			$ 3.45
Stock-based compensation		13,000
Payment for consulting services		$ 50,000
Consulting agreement term			1 year
Common Stock
Related Party Transaction [Line Items]
Stock Issued (in shares)	918,000	322,262		312,731	527,853
Warrants to purchase common stock
Related Party Transaction [Line Items]
Warrant issued	367,175

Shares Purchased by Related Parties (Detail) - USD ($)			12 Months Ended
Shares Purchased by Related Parties (Detail) - USD ($)	Jul. 08, 2015	Feb. 27, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 09, 2015
Related Party Transaction [Line Items]
Warrants Purchased						117,520
Proceeds, before expenses, to the Company	$ 16,000,000	$ 13,100,000
Common Stock
Related Party Transaction [Line Items]
Stock Issued (in shares)		918,000	322,262	312,731	527,853
Anthony Jansz
Related Party Transaction [Line Items]
Proceeds, before expenses, to the Company		$ 142,500
Anthony Jansz \| Common Stock
Related Party Transaction [Line Items]
Stock Issued (in shares)		10,000
Warrants to purchase common stock \| Anthony Jansz
Related Party Transaction [Line Items]
Warrants Purchased		4,000

Commitments and Contingencies - Additional Information (Detail) - USD ($)			12 Months Ended
	Aug. 25, 2015	Mar. 31, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005
Loss Contingencies [Line Items]
Operating lease agreement expiration date	Sep. 30, 2018		Sep. 30, 2015
Operating lease agreement term	3 years
Total rent expense			$ 262,059	$ 270,872	$ 270,872
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
Research and development expense			$ 8,141,323	$ 11,031,619	$ 11,075,493
Amendment One
Loss Contingencies [Line Items]
Collaborative obesity device research and development agreement, extension period		2 years
Retainer Fees
Loss Contingencies [Line Items]
Research and development expense								$ 250,000	$ 250,000	$ 250,000	$ 250,000	$ 250,000
Retainer Fees \| Amendment One
Loss Contingencies [Line Items]
Research and development expense						$ 100,000	$ 100,000
Retainer Fees \| Amendment No. 2
Loss Contingencies [Line Items]
Research and development expense						$ 75,000
Minimum
Loss Contingencies [Line Items]
Operating lease, monthly base rent	$ 18,925
Maximum
Loss Contingencies [Line Items]
Operating lease, monthly base rent	$ 20,345

Future Minimum Lease Payment (Detail)	Dec. 31, 2015 USD ($)
Leases Future Minimum Payments [Line Items]
2016	$ 229,233
2017	237,749
2018	183,103
Operating Leases, Future Minimum Payments Due, Total	$ 650,085

Quarterly Information (Detail) - USD ($)	3 Months Ended								12 Months Ended
Quarterly Information (Detail) - USD ($)	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Line Items]
Net loss	$ (6,770,000)	$ (4,151,000)	$ (7,404,000)	$ (7,174,000)	$ (6,181,000)	$ (5,714,000)	$ (7,501,000)	$ (6,732,000)	$ (25,498,747)	$ (26,128,720)	$ (25,780,659)
Basic and diluted net loss per share	$ (0.95)	$ (0.60)	$ (1.49)	$ (1.48)	$ (1.34)	$ (1.24)	$ (1.66)	$ (1.54)	$ (4.27)	$ (5.78)	$ (7.03)

- Definition

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

+ References + Details