Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2019	Feb. 18, 2020	Jun. 28, 2019
Document and Entity Information
Entity Registrant Name	AGILE THERAPEUTICS INC
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 52.1
Entity Common Stock, Shares Outstanding		69,810,305
Entity Central Index Key	0001261249
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 34,479	$ 7,851
Prepaid expenses	840	607
Total current assets	35,319	8,458
Property and equipment, net	14,044	13,916
Right of use and other assets	177	18
Total assets	49,540	22,392
Current liabilities:
Accounts payable	1,819	875
Accrued expenses	1,804	1,343
Lease payable, current portion	172
Total current liabilities	3,795	2,218
Total liabilities	3,795	2,218
Commitments and contingencies (Note 13)
Stockholders' equity
Common stock, $.0001 par value, 150,000,000 shares authorized, 69,810,305 and 34,377,329 issued and outstanding at December 31, 2019 and 2018, respectively	7	3
Additional paid-in capital	306,108	261,722
Accumulated deficit	(260,370)	(241,551)
Total stockholders' equity	45,745	20,174
Total liabilities and stockholders' equity	$ 49,540	$ 22,392

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Balance Sheets
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	69,810,305	34,377,329
Common stock, outstanding (in shares)	69,810,305	34,377,329

Statements of Operations - USD ($) $ in Thousands	12 Months Ended
Statements of Operations - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating expenses:
Research and development	$ 9,858	$ 9,777	$ 14,428
General and administrative	9,000	8,739	12,383
Restructuring Charges	0	1,019
Total operating expenses	18,858	19,535	26,811
Loss from operations	(18,858)	(19,535)	(26,811)
Other income (expense)
Interest income	252	366	282
Interest expense		(1,116)	(1,918)
Change in fair value of warrants		29	143
Total other income (expense), net	252	(721)	(1,493)
Loss before benefit from income taxes	(18,606)	(20,256)	(28,304)
Benefit from income taxes		477
Net loss	$ (18,606)	$ (19,779)	$ (28,304)
Net loss per share (basic and diluted) (in dollars per share)	$ (0.38)	$ (0.58)	$ (0.91)
Weighted-average common shares (basic and diluted) (in shares)	49,432,487	34,315,931	30,940,831

Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock Public offering	Common Stock Private Placement	Common Stock At-the-market sales	Common Stock	Additional Paid-in Capital Public offering	Additional Paid-in Capital Private Placement	Additional Paid-in Capital At-the-market sales	Additional Paid-in Capital	Accumulated Deficit	Public offering	Private Placement	At-the-market sales	Total
Balance at Dec. 31, 2016				$ 3				$ 235,754	$ (193,468)				$ 42,289
Balance (in shares) at Dec. 31, 2016				28,759,731
Increase (decrease) in stockholders' equity
Share-based compensation - stock options and RSUs								3,651					3,651
Issuance of common stock					$ 18,535					$ 18,535
Issuance of common stock (in shares)	5,333,334
Vesting of RSUs (in shares)				16,667
Issuance of common stock upon exercise of options								152					152
Issuance of common stock upon exercise of options (in shares)				76,610
Net loss									(28,304)				(28,304)
Balance at Dec. 31, 2017				$ 3				258,092	(221,772)				36,323
Balance (in shares) at Dec. 31, 2017				34,186,342
Increase (decrease) in stockholders' equity
Share-based compensation - stock options and RSUs								3,630					3,630
Vesting of RSUs (in shares)				190,987
Net loss									(19,779)				(19,779)
Balance at Dec. 31, 2018				$ 3				261,722	(241,551)				20,174
Balance (in shares) at Dec. 31, 2018				34,377,329
Increase (decrease) in stockholders' equity
Adjustment to derivative liabilities upon adoption of ASU 2017-11								213	(213)
Share-based compensation - stock options and RSUs								1,762					1,762
Issuance of common stock	$ 2	$ 1	$ 1		$ 12,685	$ 7,809	$ 21,753			$ 12,687	$ 7,810	$ 21,754
Issuance of common stock (in shares)	14,526,315	8,426,750	12,242,436
Vesting of RSUs (in shares)				145,204
Issuance of common stock upon exercise of options								164					164
Issuance of common stock upon exercise of options (in shares)				92,271
Net loss				$ 0				0	(18,606)				(18,606)
Balance at Dec. 31, 2019				$ 7				$ 306,108	$ (260,370)				$ 45,745
Balance (in shares) at Dec. 31, 2019				69,810,305

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (18,606)	$ (19,779)	$ (28,304)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	18	23	23
Amortization	145
Noncash stock based compensation	1,762	3,630	3,651
Noncash interest		282	667
Change in fair value of warrants		(29)	(143)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(233)	155	2,006
Accounts payable and accrued expenses	1,377	(1,177)	(2,460)
Lease liability	(152)
Net cash used in operating activities	(15,689)	(16,895)	(24,560)
Cash flows from investing activities:
Acquisition of property and equipment	(98)	(318)	(1,313)
Net cash used in investing activities	(98)	(318)	(1,313)
Cash flows from financing activities:
Principal payments of long-term debt		(10,888)	(5,612)
Proceeds from exercise of stock options	164		152
Net cash provided by (used in) financing activities	42,415	(10,888)	13,075
Net increase (decrease) in cash and cash equivalents	26,628	(28,101)	(12,798)
Cash and cash equivalents, beginning of year	7,851	35,952	48,750
Cash and cash equivalents, end of year	34,479	7,851	35,952
Supplemental cash flow information
Interest paid during the year		$ 1,370	1,295
Non-cash transactions
Property and equipment purchases included in accounts payable	49		242
At-the-market sales
Cash flows from financing activities:
Proceeds from sales or issuance of common stock, net of offering costs	$ 42,251		$ 18,535

Organization and Description of Business	12 Months Ended
Organization and Description of Business	Dec. 31, 2019
Organization and Description of Business
Organization and Description of Business	1. Organization and Description of Business Nature of Operations Agile Therapeutics, Inc. (“Agile" or the "Company") was incorporated in Delaware on December 22, 1997. Agile is a women's healthcare company dedicated to fulfilling the unmet health needs of today's women. The Company's activities since inception have consisted principally of raising capital and performing research and development, including development of the Company’s lead product candidate. The Company is headquartered in Princeton, New Jersey. The Company’s sole approved product, Twirla®, also known as AG200-15, is a once-weekly prescription contraceptive patch that received approval from the U.S. Food and Drug Administration, or FDA in February 2020. Substantially all of the Company’s resources are currently dedicated to commercializing Twirla in the United States. The Company has not generated product revenue to date and is subject to a number of risks similar to those of other early stage companies, including, but not limited to, dependence on key individuals, the difficulties and uncertainties inherent in the development of commercially usable products, market acceptance of products, protection of proprietary technology, the potential need to obtain additional capital necessary to fund the development of its products, competition from larger companies and compliance with the FDA and other government regulations. If the Company does not successfully commercialize any product candidates, it will be unable to generate recurring product revenue or achieve profitability. The Company has incurred operating losses and negative cash flows from operating activities each year since inception. As of December 31, 2019, the Company had an accumulated deficit of approximately $260 million. The Company expects to continue to incur net losses into the foreseeable future The Company has financed its operations to date primarily through the issuance and sale of its common stock in both public and private offerings (see Note 9), private placements of its convertible preferred stock, venture loans, and non-dilutive grant funding. Going Concern As of December 31, 2019, the Company had cash and cash equivalents of $34.5 million. Additionally, in February 2020, the Company entered into a Credit Agreement and Guaranty with Perceptive Credit Holdings III, LP, or the Perceptive Credit Agreement. A first tranche of $5.0 million was funded on execution of the Perceptive Credit Agreement. A second tranche of $15.0 million was funded as a result of the approval of Twirla by the FDA (see Note 15). The Company believes that its cash and cash equivalents as of December 31, 2019 along with the proceeds of the Perceptive Credit Agreement received by the date of this report will be sufficient to meet its projected operating requirements through the end of 2020. The Company will require additional capital to fund its operating needs beyond 2020, which primarily will include commercializing Twirla, and exploring the advancement of its existing pipeline and its possible expansion through business development activities. The Company anticipates it will continue to incur net losses for the foreseeable future and the Company's ability to continue operations beyond 2020 will depend on its ability to obtain additional capital, as to which no assurances can be given. There can be no assurance that any financing by the Company can be realized by the Company, or if realized, what the terms of any such financing may be, or that any amount that the Company is able to raise will be adequate. Based upon the foregoing, management has concluded that there is substantial doubt about the Company's ability to continue as a going concern through the 12 months following the date on which this Annual Report on Form 10-K is filed. The Company continues to analyze various alternatives, including strategic and refinancing alternatives, asset sales and mergers and acquisitions. The Company's future success depends on its ability to raise additional capital and/or implement the various strategic alternatives discussed above. The Company cannot be certain that these initiatives or raising additional capital, whether through selling additional debt or equity securities or obtaining a line of credit or other loan, will be available to it or, if available, will be on terms acceptable to the Company. If the Company issues additional securities to raise funds, these securities may have rights, preferences, or privileges senior to those of its common stock, and the Company's current stockholders will experience dilution. If the Company is unable to obtain funds when needed or on acceptable terms, the Company then may be unable to complete the commercialization of Twirla, and may also be required to cut operating costs, and forego future development and other opportunities. The audited financial statements as of December 31, 2019 have been prepared under the assumption that the Company will continue as a going concern for the next 12 months. The Company’s ability to continue as a going concern is dependent upon its uncertain ability to obtain additional capital, reduce expenditures and/or execute on its business plan and successfully launch Twirla. The audited financial statements as of December 31, 2019 do not include any adjustments that might result from the outcome of this uncertainty. If the Company is unable to continue as a going concern, it may have to liquidate its assets and may receive less than the value at which those assets are carried on the financial statements.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Polices

Basis of Presentation

The accompanying financial statements have been prepared in accordance with United States generally accepted accounting principles ("U.S. GAAP") and include all adjustments necessary for the fair presentation of the Company's financial position for the periods presented.

Use of Estimates

The preparation of the Company’s financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company bases its estimates and judgments on historical experience and various other assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company’s balance sheets and the amounts of expenses reported for each of the periods presented are affected by estimates and assumptions, which are used for, but not limited to, the accounting for common stock warrants, stock‑based compensation, income taxes, and accounting for research and development costs. Actual results could differ from those estimates.

Risks and Uncertainties

While Twirla has been approved by the FDA, other potential product candidates developed by the Company will require approval from the FDA prior to commercial sales. There can be no assurance that the Company’s other product candidates will receive the required approval. If the Company is denied approval or such approval is delayed, or is unable to obtain the necessary financing to complete development and approval, there could be a material adverse impact on the Company’s financial condition and results of operations.

Cash and Cash Equivalents

The Company considers all highly‑liquid investments with an original maturity of three months or less when purchased to be cash equivalents. All cash and cash equivalents are held in United States financial institutions. Cash and cash equivalents include money market funds that invest primarily in commercial paper and U.S. government and U.S. government agency obligations.

The Company maintains balances with financial institutions in excess of the Federal Deposit Insurance Corporation limit.

Fair Value of Financial Instruments

In accordance with Accounting Standards Codification (“ASC”) 825, Financial Instruments, disclosures of fair value information about financial instruments are required, whether or not recognized in the balance sheet, for which it is practicable to estimate that value. Cash and cash equivalents are carried at fair value (see Note 3).

Other financial instruments, including accounts payable and accrued liabilities, are carried at cost, which approximates fair value given their short‑term nature.

Property and Equipment

Property and equipment, consisting of manufacturing, office and computer equipment, is stated at cost, less accumulated depreciation. Depreciation is computed using the straight‑line, method over the estimated useful lives of the assets.

Expenditures incurred after the fixed assets have been put into operation, such as repairs and maintenance, are charged to earnings in the period in which costs are incurred. Improvements and additions are capitalized in accordance with Company policy.

Long-Lived Assets

In accordance with ASC 360, Property, Plant and Equipment, the Company’s policy is to review long‑lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Management does not believe that there has been any impairment of the carrying value of any long‑lived assets as of December 31, 2019.

Research and Development Expense

Research and development costs are expensed as incurred. Research and development expense consists primarily of costs related to personnel, including salaries and other personnel‑related expenses, expenses related to manufacturing, clinical trial expenses, consulting fees and support services used in drug development. All research and development costs are charged to operations as incurred in accordance with ASC 730, Research and Development.

In certain circumstances, the Company is required to make advance payments to vendors for goods or services that will be received in the future for use in research and development activities. In such circumstances, the advance payments are deferred and are expensed when the activity has been performed or when the goods have been received.

Deferred Financing Costs

Costs directly attributable to the Company’s term loan (see Note 8) are deferred and reported as a reduction of the related term loan. These costs represent legal fees and other costs related to the term loan and are being amortized over the term of the loan. Amortization of deferred financing costs charged to interest expense was approximately $0, $133 and $239 for the years ended December 31, 2019, 2018 and 2017, respectively.

Concentrations of Credit Risk

Financial instruments which potentially subject the Company to credit risk consist principally of cash and cash equivalents. All cash and cash equivalents are held in business checking and money market accounts in United States financial institutions the balances of which exceed federally insured limits. The Company has not recognized any losses from credit risks on such accounts. The Company believes it is not exposed to significant credit risks on cash and cash equivalents. The Company has no financial instruments with off‑balance sheet risk of accounting loss.

Warrants

The Company accounts for its warrants to purchase redeemable convertible stock in accordance with ASC 480, Distinguishing Liabilities from Equity. ASC 480 requires that a financial instrument, other than an outstanding share, that, at inception, is indexed to an obligation to repurchase the issuer’s equity shares, regardless of the timing or the probability of the redemption feature and may require the issuer to settle the obligation by transferring assets be classified as a liability. The Company measures the fair value of its warrant liability using the Black-Scholes option-pricing model with changes in fair value recognized as increases or reductions to other income (expense) in the statement of operations.

In connection with the completion of the Company's initial public offering in May 2014, the warrants to purchase shares of Series A-1 and Series A-2 preferred stock expired unexercised and the warrants to purchase shares of Series C preferred stock automatically converted into warrants to purchase shares of common stock. Warrants with non-standard anti-dilution provisions (referred to as down round protection) are classified as liabilities and re-measured each reporting period. On January 1, 2019, the Company adopted the provisions of Accounting Standards Update (“ASU”) 2017-11 Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part 1) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Non-controlling Interests with a Scope Exception, which indicates that a down round feature no longer precludes equity classification when assessing whether an investment is indexed to an entity’s own stock. The Company used a modified retrospective approach to adoption, which does not restate its financial statements as of the prior year end (December 31, 2018). The cumulative effect of adoption of ASU 2017-11 resulted in an adjustment to accumulated deficit as of January 1, 2019 of $213 with a corresponding adjustment to additional paid-in capital. Warrants to purchase 62,505 shares of common stock at $6.00 per share expired on December 14, 2019, and none of these warrants are outstanding as of December 31, 2019.

The warrants issued in connection with the Company's debt financing completed in February 2015 (see Note 8) are classified as a component of stockholders' equity. The value of such warrants was determined using the Black-Scholes option-pricing model. As of December 31, 2019, there were outstanding 180,274 warrants to purchase common stock at $5.89 per share related to this debt financing. These warrants expire on February 24, 2020.

Income Taxes

The Company accounts for deferred taxes using the asset and liability method as specified by ASC 740, Income Taxes. Deferred income tax assets and liabilities are determined based on differences between the financial statement reporting and the tax basis of assets and liabilities, operating losses and tax credit carryforwards. Deferred income taxes are measured using the enacted tax rates and laws that are anticipated to be in effect when the differences are expected to reverse. The measurement of deferred income tax assets is reduced, if necessary, by a valuation allowance for any tax benefits which are not expected to be realized. The effect on deferred income tax assets and liabilities of a change in tax rates is recognized in the period that such tax rate changes are enacted.

The Company has adopted the authoritative guidance on accounting for and disclosure of uncertainty in tax positions which prescribes a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns. The Company has no uncertain tax positions as of December 31, 2019 that qualifies for either recognition or disclosure in the financial statements under this guidance.

Stock‑Based Compensation

The Company accounts for stock-based compensation in accordance with ASC 718, Compensation-Stock Compensation. The Company grants stock options for a fixed number of shares to employees and non-employees with an exercise price equal to the fair value of the shares at grant date. Compensation cost is recognized for all share-based payments granted and is based on the grant-date fair value estimated using the weighted-average assumption of the Black-Scholes option pricing model based on key assumptions such as stock price, expected volatility and expected term. The Company elects to account for forfeitures when they occur. The equity instrument is not considered to be issued until the instrument vests. As a result, compensation cost is recognized over the requisite service period with an offsetting credit to additional paid-in capital.

The Company also awards restricted stock units (“RSUs”) to employees and its board of directors. RSUs are generally subject to forfeiture if employment terminates prior to the completion of the vesting restrictions. The Company expenses the cost of the RSUs, which is determined to be the fair market value of the shares of common stock underlying the RSUs at the date of grant, ratably over the period during which the vesting restrictions lapse. Cost associated with performance-based restricted stock units with a performance condition which affects the vesting is recognized only if the performance condition is probable of being satisfied.

Segment Information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating and reporting segment, which is the business of developing its transdermal patch for use in contraception.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding plus the effect of dilutive potential common shares outstanding during the period determined using the treasury-stock and if-converted methods. For purposes of diluted net loss per share calculation, common stock warrants, unvested RSUs and stock options are considered to be potentially dilutive securities but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented.

The following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share for the years ended December 31, 2019, 2018 and 2017, respectively, because to do so would be anti-dilutive (in common equivalent shares):


	Year Ended December 31,
	2019	2018	2017
Common stock warrants	180,274	242,779	242,779
Unvested restricted stock units	—	147,554	264,361
Common stock options	7,192,357	5,687,901	3,805,305
Total	7,372,631	6,078,234	4,312,445

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that the Company adopts as of the specified effective date. Unless otherwise discussed below, the Company does not believe that the adoption of recently issued standards have or may have a material impact on our consolidated financial statements or disclosures.

In February 2016, the FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the statement of operations. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The Company adopted ASU No. 2016-02 on January 1, 2019. The Company recorded a lease asset and lease liability of approximately $0.3 million on its balance sheet as of January 1, 2019, with no impact on its statement of operations.

In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part 1) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception. This ASU eliminates the requirement to consider “down round” features when determining whether certain equity-linked financial instruments or embedded features are indexed to an entity’s own stock. On January 1, 2019, the Company adopted the provisions of ASU No. 2017-11 using a modified retrospective approach, which does not restate its financial statements as of the prior year end (December 31, 2018). The cumulative effect of adoption of ASU 2017-11 resulted in an adjustment to accumulated deficit as of January 1, 2019 of $213 with a corresponding adjustment to additional paid-in capital. As a result of the adoption of ASU 2017-11, effective January 1, 2019, the Company no longer measures these warrants at fair value.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation—Stock Compensation, to change the terms or conditions of a share-based payment award. The amendments in this ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. This Update is the final version of Proposed ASU 2016-360—Compensation—Stock Compensation (Topic 718)—Scope of Modification Accounting, which has been deleted. The amendments in this ASU are effective for all entities for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The adoption of this ASU did not have a material impact on the Company's financial statements.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"), which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses rather than incurred losses to estimate credit losses on certain types of financial instruments, including trade receivables. ASU 2016-13 was adopted by the Company on January 1, 2020 and has no current impact on the Company as we do not have any financial instruments covered by the topic.

Management does not believe that any other recently issued, but not yet effective accounting pronouncements, if adopted, would have a material impact on the accompanying financial statements.

Fair Value Measurements

12 Months Ended

Dec. 31, 2019

Fair Value Measurements

Fair Value Measurements

3. Fair Value Measurements

ASC 820, Fair Value Measurements and Disclosures, describes the fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value.

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three‑level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable inputs and minimizes the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows:

Level 1—Quoted prices in active markets for identical assets and liabilities. The Company’s Level 1 assets consist of cash and cash equivalents. The Company has no Level 1 liabilities.

Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted market prices for similar assets or liabilities in active markets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets and liabilities. The Company has no Level 2 assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market data and which require internal development of assumptions about how market participant price the fair value of the assets or liabilities. The Company has no Level 3 assets or liabilities.

The following tables set forth the Company’s financial instruments measured at fair value by level within the fair value hierarchy as of December 31, 2019 and 2018:


	Level 1		Level 2		Level 3
2019
Assets:
Cash equivalents	$	34,444	$	—	$	—
Total assets at fair value	$	34,444	$	—	$	—


	Level 1		Level 2		Level 3
2018
Assets:
Cash equivalents	$	7,776	$	—	$	—
Total assets at fair value	$	7,776	$	—	$	—

The following is a roll forward of the fair value of Level 3 warrants:


Beginning balance at December 31, 2016	$	172
Change in fair value		(143)
Ending balance at December 31, 2017		29
Change in fair value		(29)
Ending balance at December 31, 2018		—
Change in fair value		—
Ending balance at December 31, 2019	$	—

There were no transfers between Level 1, 2 or 3 during 2019 or 2018.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Prepaid Expenses

12 Months Ended

Dec. 31, 2019

Prepaid Expenses

Prepaid Expenses

4. Prepaid Expenses

Prepaid expenses consist of the following:


	December 31,
	2019		2018
Prepaid insurance	$	656	$	484
Other		184		123
Total prepaid expenses	$	840	$	607

Property and Equipment

12 Months Ended

Dec. 31, 2019

Property and Equipment

Property and Equipment

5. Property and Equipment


	December 31,
	2019		2018		Estimated Life
Office equipment	$	49	$	49	3 - 10 years
Computer equipment		179		175	3 years
Manufacturing equipment		14,203		14,061	5 years
		14,431		14,285
Less: accumulated depreciation		(387)		(369)
Property and equipment	$	14,044	$	13,916

As of December 31, 2019, and 2018, manufacturing equipment includes approximately $14.0 million and $13.9 million, respectively, of equipment which is in the process of being constructed and qualified and is not currently being depreciated.

Accrued Liabilities

12 Months Ended

Dec. 31, 2019

Accrued Liabilities

Accrued Liabilities

6. Accrued Liabilities

Accrued liabilities consist of the following:


	December 31,
	2019		2018
Employee bonuses	$	1,437	$	621
Accrued retention bonus		—		638
Accrued professional fees and other		367		84
Total accrued liabilities	$	1,804	$	1,343

Leases

12 Months Ended

Dec. 31, 2019

Leases

Leases

7. Leases

In February 2016, the FASB issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the statement of operations. The Company adopted ASU No. 2016-02 on January 1, 2019 for leases that existed on that date. The Company has elected to apply the provisions of ASC 842 modified retrospectively at January 1, 2019 through a cumulative-effect adjustment. Prior period results continue to be presented under ASC 840 based on the accounting standards originally in effect for such periods. The company recorded a lease asset and lease liability of approximately $0.3 million on its balance sheet as of January 1, 2019, with no impact on its statement of operations.

The Company has no finance leases and one operating lease for office space in Princeton, NJ. Operating lease expense was $193 for the year ended December 31, 2019.

Operating cash flows used for operating leases during the year ended December 31, 2019 were $152. As of December 31, 2019, the weighted-average remaining lease term was 0.92 years and the weighted average discount rate was 21.2%.

Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows:


2020	$	191
Total	$	191
Less: Interest		(19)
Present value of lease liability	$	172

Loan and Security Agreement	12 Months Ended
Loan and Security Agreement	Dec. 31, 2019
Loan and Security Agreement
Loan and Security Agreement	8. Loan and Security Agreement Hercules Capital, Inc. In February 2015, the Company entered into a loan and security agreement (the "Hercules Loan Agreement") with Hercules Capital, Inc. ("Hercules") for a term loan of up to $25.0 million. In August 2016, the Company entered into the First Amendment to Loan and Security Agreement (the "First Amendment") with Hercules which amended certain terms of the Hercules Loan Agreement. In May 2017, the Company entered into the Second Amendment to Loan and Security Agreement (the “Second Amendment”) with Hercules which further amended certain terms of the Hercules Loan Agreement. A first tranche of $16.5 million was funded upon execution of the Hercules Loan Agreement, approximately $15.5 million of which was used to repay the Company's previous term loan with Oxford Finance LLC. The First Amendment extended the Company's option to draw down the second tranche of $8.5 million (the "Second Term Loan Advance") of the term loan facility provided under the Hercules Loan Agreement (the "Term Loan") until March 31, 2017 and made the Second Term Loan Advance subject to the consent of Hercules, among other customary conditions. The Second Amendment further extended the Company's option to draw the Second Term Loan Advance until January 31, 2018 and continued to make the Second Term Loan Advance subject to the consent of Hercules, among other customary conditions. The First Amendment also extended the interest-only payments until January 31, 2017, in connection with the first tranche of $16.5 million (the "First Term Loan Advance" and together with the Second Term Loan Advance, the "Term Loan Advances"). The period during which the additional tranche of $8.5 million may be drawn has expired and therefore the $8.5 million can no longer be drawn by the Company. The First Amendment provided the Term Loan matured on December 1, 2018. As a result of the First Amendment, and in connection with the extension of the interest-only period from the First Term Loan Advance, Hercules returned to the Company the principal payments paid by the Company in July and August 2016, which such returned payments once again constituted outstanding Term Loan advances under the Hercules Loan Agreement. In connection with the execution of the First Amendment, the Company paid Hercules a facility fee of $165. The facility fee represented a debt issue cost which was reflected as a reduction to the carrying amount of the loan payable in accordance with ASU 2015-03. Such issue costs were amortized to interest expense over the life of the Term Loan using the effective interest method. As of December 31, 2019, and 2018, the Company had no outstanding borrowings related to the Hercules Loan Agreement. The Term Loan accrued interest at a rate of the greater of 9.0% or 9.0% plus Prime minus 4.25% and was payable monthly. Principal was due in 23 consecutive monthly installments beginning on February 1, 2017 and ending on December 1, 2018. In addition to the outstanding principal balance, the Company was required to make a final payment of approximately $611 on the maturity date of the Hercules Loan (December 1, 2018). The amount of the end of term final payment was accrued over the loan term as interest expense. The obligations of the Company under the Hercules Loan Agreement were secured by a perfected first position lien on all of the assets of the Company, excluding intellectual property assets. In connection with the Hercules Loan Agreement, the Company issued Hercules a warrant to purchase 180,274 shares of the Company’s common stock at an exercise price of $5.89 per share which expires on February 24, 2020 and granted Hercules the right to participate in future equity financings in an amount up to $2.0 million while the loan or warrant are outstanding. The Company allocated the proceeds of $16.5 million in accordance with ASC 470 based on the relative fair values. The relative fair value of the warrants of approximately $1.2 million at the time of issuance, which was determined using the Black-Scholes option-pricing model, was recorded as additional paid-in capital and reduced the carrying value of the debt. The significant assumptions used in preparing the option pricing model for valuing the Company's warrant issued to Hercules include (i) volatility (75.0%), (ii) risk free interest rate of 1.22% (estimated using treasury bonds with a 4-year life), (iii) strike price ($5.89) for the common stock warrant, (iv) fair value of common stock ($9.82) and (v) expected life (4 years). The discount on the debt was amortized to interest expense over the term of the debt. Interest expense on the Hercules Loan Agreement including the accretion of the value of the related warrants, accrual of term loan back-end fee and amortization of the deferred financing costs was approximately $0, $1.1 million and $1.9 million, for the years ended December 31, 2019, 2018 and 2017, respectively.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2019
Stockholders' Equity
Stockholders' Equity	9. Stockholders’ Equity The Company’s Certificate of Incorporation, among other things: (i) authorizes 150,000,000 shares of common stock; (ii) authorizes 10,000,000 shares of undesignated preferred stock that may be issued from time to time by the Board in one or more series; (iii) provides that the Board be divided into three classes with staggered three-year terms, with one class of directors to be elected at each annual meeting of the Company’s stockholders; (iv) provides that directors may only be removed with cause and only upon the affirmative vote of holders of at least 75% of the voting power of all then-outstanding shares of capital stock of the Company entitled to vote generally in the election of directors; (v) provides that only the Board, the chairman of the Board or the chief executive officer may call a special meeting of stockholders; and (vi) requires that any action instituted against the Company’s officers or directors in connection with their service to the Company be brought in the State of Delaware. Shelf Registration Statements On June 19, 2015, the Company filed a universal shelf registration statement with the SEC for the issuance of common stock, preferred stock, warrants, rights, debt securities and units up to an aggregate amount of $150.0 million (the "2015 Shelf Registration Statement"). On July 1, 2015, the 2015 Shelf Registration Statement was declared effective by the SEC. The Company completed an offering of common stock in both January 2016 and August 2017 utilizing the 2015 Shelf Registration Statement. The 2015 Shelf Registration Statement expired on June 30, 2018. On November 2, 2018, the Company filed a universal shelf registration statement with the Securities and Exchange Commission (“SEC”) for the issuance of common stock, preferred stock, warrants, rights, debt securities and units up to an aggregate amount of $100.0 million (the "2018 Shelf Registration Statement"). On November 14, 2018, the 2018 Shelf Registration Statement was declared effective by the SEC. In the future, the Company may periodically offer one or more of these securities in amounts, prices and terms to be announced when and if the securities are offered. At the time any of the securities covered by the 2018 Shelf Registration Statement are offered for sale, a prospectus supplement will be prepared and filed with the SEC containing specific information about the terms of any such offering. On January 23, 2019, the Company filed a prospectus supplement to its 2018 Shelf Registration Statement registering an at-the-market offering program we entered into for the sale of up to $10.0 million of shares of our common stock. In the year ended December 31, 2019, the Company sold a total of 1,801,528 shares of our common stock under this ATM program resulting in net proceeds of approximately $2.5 million. We terminated this at-the-market offering program on July 31, 2019. In August 2019, the Company filed a prospectus supplement to its 2018 Shelf Registration Statement registering a public offering of 14,526,315 shares of common stock at a price of $0.95 per share. Proceeds from the public offering, net of underwriting discounts, commissions and offering expenses, were approximately $12.7 million. On November 8, 2019, the Company filed a prospectus supplement to its 2018 Shelf Registration Statement registering an at-the-market offering program we entered into for the sale of up to $20.0 million of shares of our common stock. In the year ended December 31, 2019, we sold a total of 10,440,908 shares of our common stock under this ATM program resulting in net proceeds of approximately $19.3 million. Private Placement In March 2019, the Company completed a private placement of 8,426,750 shares of common stock at $0.93 per share. Proceeds from the Company’s private placement, net of offering costs were approximately $7.8 million. 2016 Public Offering of Common Stock In January 2016, the Company completed an underwritten public offering of 5,511,812 shares of its common stock at a public offering price of $6.35 per share. In February 2016, the underwriters of the public offering of common stock exercised in full their option to purchase an additional 826,771 shares of common stock at the public offering price of $6.35 per share, less underwriting discounts and commissions. A total of 6,338,583 shares of common stock were sold in the public offering resulting in total net proceeds of approximately $37.5 million. One of the Company’s stockholders, who is also affiliated with a member of the Board, purchased 393,700 shares of common stock for approximately $2.5 million in the public offering. 2017 Public Offering of Common Stock In August 2017, the Company completed an underwritten public offering of 5,333,334 shares of its common stock at a public offering price of $3.75 per share. Proceeds from this offering, net of underwriting discounts, commissions and other offering costs were approximately $18.5 million.

Equity Incentive Plans

12 Months Ended

Dec. 31, 2019

Equity Incentive Plans

Equity Incentive Plans

10. Equity Incentive Plans

Stock options

The Company had granted stock options under an amended and restated 1997 Equity Incentive Plan (the “1997 Plan”) and a 2008 Equity Incentive Plan (the “2008 Plan”). The plans provided for the granting of incentive and non-statutory options and stock awards to consultants, directors, officers and employees. Such options are exercisable for a period of ten years and generally vest over a four-year period. In conjunction with the adoption of the 2008 Plan in April 2008, no additional grants were made from the 1997 Plan and issued options from the 1997 Plan remain outstanding. In 2014, the Board approved the 2014 Equity Incentive Plan (the “2014 Plan”). The 2014 Plan is the successor to the Company’s 2008 Plan and 1997 Plan. In conjunction with the adoption of the 2014 Plan in 2014, no additional grants were made from the 2008 Plan and options from the 1997 Plan and the 2008 Plan remain outstanding. In June 2018, the 2014 Plan was amended and restated, and the Amended and Restated 2014 Incentive Compensation is now referred to as the Amended 2014 Plan. As of December 31, 2019, there were 2,170,175 shares available for future grant under the Amended 2014 Plan.

Through December 31, 2019, the Company granted options to certain employees and nonemployees to purchase shares of common stock at exercise prices ranging from $0.58 to $10.75 per share. The Company recorded noncash stock-based compensation expense for the years ended December 31, 2019, 2018 and 2017 based on the fair market value of the options and shares granted at the grant date. Stock‑based compensation expense was as follows:


	Year Ended December 31,
	2019		2018		2017
Research and development	$	522	$	1,274	$	1,184
General and administrative		1,240		2,356		2,467
Total	$	1,762	$	3,630	$	3,651

The following assumptions were used to compute employee stock‑based compensation under the Black‑Scholes option pricing model:


	2019					2018		2017
Risk-free interest rate	1.74	%	-	2.61	%	2.57	%	2.27	%
Expective volatility				65.0	%	70.0	%	73.9	%
Expected dividend yield				0	%	0	%	0	%
Expected life (in years)				6.25		6.25		6.25

Risk‑free interest rate. The Company bases the risk‑free interest rate assumption on observed interest rates appropriate for the expected term of the stock option grants.

Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present intention to pay cash dividends.

Expected volatility. The expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on comparable companies in the biotechnology and pharmaceutical industries.

Expected term. The expected term represents the period of time that options are expected to be outstanding. Because the Company does not have historic exercise behavior, management determined the expected life assumption using the simplified method, which is an average of the contractual term of the option and its ordinary vesting period.

Forfeitures. The Company has elected to record forfeitures as they occur.

As of December 31, 2019, the unrecorded deferred stock‑based compensation balance related to stock options was approximately $1.9 million and will be recognized over an estimated weighted‑average amortization period of 1.4 years. The weighted average grant date fair value of options granted during the year ended December 31, 2019 was $0.59.

The following table summarizes the options outstanding, options vested and the options exercisable as of December 31, 2019, 2018 and 2017:


				Weighted
		Weighted		Average
		Average		Remaining
		Exercise		Contractual	Aggregate
	Options	Price		Life (Years)	Intrinsic Value
Options outstanding at December 31, 2017	3,805,305		5.74	7.4
Options granted	2,230,000		1.96
Options exercised	—		—
Options cancelled/forfeited	(347,404)		4.19
Options outstanding at December 31, 2018	5,687,901		4.34	7.4
Options granted	2,805,600		1.18
Options exercised	(92,271)		1.78
Options cancelled/forfeited	(1,208,873)		2.70
Options outstanding at December 31, 2019	7,192,357		3.42	7.2	$	5,256
Options exercisable at December 31, 2019	4,396,577		4.60	6.1	$	2,228
Vested and expected to vest at December 31, 2019	7,192,357				$	5,256

Intrinsic value in the tables was calculated as the difference between the Company's stock price at December 31, 2019, of $2.50 per share, and the exercise price, multiplied by the number of options.

Restricted Stock Units

During the year ended December 31, 2016, the Company granted 50,000 RSUs to an employee of the Company, 16,666 RSUs vested on the grant date, 16,667 RSUs vested in February 2017 and the remaining 16,667 RSUs vested in February 2018.

During the year ended December 31, 2017, the Company granted a total of 247,694 RSUs to executive officers and directors of the Company. These RSUs vested ratably over a two-year period for the executive officers and on the one-year anniversary of the grant date for the directors.

During the year ended December 31, 2018, the Company granted a total of 108,254 RSUs to executive officers of the Company representing payment for 2017 target bonuses. These RSUs vested on the one-year anniversary of the grant date.

The following table shows the Company's restricted stock unit activity during the years ended December 31, 2019, 2018 and 2017:



		Weighted Average		Aggregate
	Shares	Grant Date Fair Value		Intrinsic Value
Restricted stock units outstanding at December 31, 2017	264,361		3.16
Granted	108,254		3.46
Vested	(225,061)		3.39	$	370
Restricted stock units outstanding at December 31, 2018	147,554		3.03
Vested	(147,554)		3.03	$	129
Restricted stock units outstanding at December 31, 2019	—

Performance Based Restricted Stock Awards

In addition to the RSUs detailed in the table above, during 2017 the Company granted up to 260,000 shares of performance-based restricted stock units (“Performance Units”) under the Company’s Amended 2014 Incentive Compensation Plan, to executive officers which are primarily contingent upon achievement of performance goals during the performance period beginning on the date of grant and ending on December 31, 2018 as set forth in each officer’s performance unit agreement. For awards with a performance condition which affects the vesting of the Performance Units, cost is recognized only if the performance condition is probable of being satisfied. Given the uncertainty of the achievement of the performance goals during the performance period, the Company did not record compensation expense related to these awards for the year ended December 31, 2017. These performance-based restricted stock units expired and were subsequently replaced with new awards in January 2018 (see below).

In January 2018, the Company granted up to 365,000 shares of performance-based restricted stock units ("Performance Units") under the Company's 2014 Incentive Compensation Plan primarily to executive officers, which were largely contingent upon the achievement of performance goals during the performance period beginning on the date of grant and ending on December 31, 2019 as set forth in each individual's Performance Unit agreement. Performance Units granted in January 2018 replaced Performance Units granted in April 2017 which expired. During 2018, 50,000 Performance Units were cancelled and as of December 31, 2018 315,000 Performance Units remained outstanding. The remaining 315,000 Performance Units expired in December 2019 as the performance goals were not achieved, and there are no Performance Units outstanding as of December 31, 2019.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Taxes

Income Taxes

11. Income Taxes

On December 22, 2017, the President of the United States signed into law an Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018 (commonly known as “the Tax Cuts and Jobs Act or the “TCJA””), which introduced a comprehensive set of tax reforms. The Tax Cuts and Jobs Act significantly revises U.S. tax law by, among other provisions, lowering the Company’s corporate tax rate from 34% to 21% and eliminating or reducing certain income tax deductions.

In December 2017, in accordance with the SEC Staff Accounting Bulletin ("SAB") 118–Income Tax Accounting Implications of the TCJA, the Company recorded tax effects on a provisional basis based on a reasonable estimate. The TCJA did not have a material impact on the Company's financial statements because its deferred temporary differences are fully offset by a valuation allowance and the Company does not have any offshore earnings from which to record the mandatory transition tax. During 2018, the Company completed its analysis under SAB 118 and no additional tax effects due to rate-remeasurement were required to be recorded.

As of December 31, 2019, the Company had available net operating loss carryforwards (“NOLs”) of approximately $231.5 million for federal and $92.4 million for state income tax reporting purposes. Under TCJA, the federal NOLs generated in 2019 and 2018, approximately $32.5 million, can be carried forward indefinitely, while the NOLs generated through taxable years ending December 31, 2017, approximately $198.9 million, are available to offset future federal taxable income, if any, through 2037. The Company also has research and development tax credit carryforwards of approximately $6.3 million and $1.6 million for federal and state income tax reporting purposes, respectively, which are available to reduce federal income taxes, if any, through 2039 and state income taxes, if any, through 2034.

The Internal Revenue Code of 1986, as amended (the “Code”) provides for a limitation on the annual use of NOLs and other tax attributes (such as research and development tax credit carryforwards) following certain ownership changes, as defined by the Code that could significantly limit the Company’s ability to utilize these carryforwards. At this time, the Company has not completed a study to assess whether an ownership change under Section 382 of the Code has occurred, or whether there have been multiple ownership changes since the Company’s formation, due to the costs and complexities associated with such a study. The Company is likely to have experienced various ownership changes, as defined by the Code, as a result of past financings. Accordingly, the Company’s ability to utilize the aforementioned carryforwards may be limited. Additionally, U.S. tax laws limit the time during which these carryforwards may be applied against future taxes. Therefore, the Company may not be able to take full advantage of these carryforwards for federal and state income tax purposes. The Company does not have any significant unrecognized tax benefits.

As of December 31, 2019, the Company has not accrued interest or penalties related to uncertain tax positions. The Company’s tax returns for the years ended December 31, 2016 through December 31, 2018 are still subject to examination by major tax jurisdictions. However, the Internal Revenue Service (“IRS”) and state tax jurisdictions can audit the NOLs generated in prior years in the years that those NOLs are utilized.

For all years through December 31, 2019, the Company generated research credits but has not conducted a study to document the qualified activities. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed and any adjustment in known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the deferred tax asset established for the research and development credit carryforwards and the valuation allowance.

The tax effects of temporary differences that give rise to significant portions of the deferred tax assets are presented below:


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	55,216	$	51,240
Research credit carryforward		7,609		6,904
Stock options and other		3,225		2,655
Total gross deferred tax assets		66,050		60,799
Valuation allowance for deferred tax assets		(66,050)		(60,799)
Net deferred tax assets	$	—	$	—

The net change in the valuation allowance for the years ended December 31, 2019 and 2018 was an increase of $5.3 million and an increase of $4.8 million, respectively.

A reconciliation of the U.S. statutory income tax rate to the Company’s effective tax rate is as follows:


	December 31,
	2019		2018		2017
Federal income tax at statutory rate	21.0	%	21.0	%	34.0	%
State income tax benefit, net of federal benefit	7.0	%	6.0	%	6.0	%
Research and development tax credits	4.0	%	3.0	%	3.0	%
Effect of tax rate changes	0.0	%	0.0	%	-94.0	%
Other	-4.0	%	-4.0	%	-1.0	%
Decrease (increase) to valuation allowance	-28.0	%	-24.0	%	52.0	%
Effective income tax rate	0.0	%	2.0	%	0.0	%

Sale of New Jersey Net Operating Losses

2018

The Company has participated in the State of New Jersey’s Technology Business Tax Certificate Transfer Program (the “Program”) sponsored by The New Jersey Economic Development Authority. The Program enables approved biotechnology companies with unused NOLs and unused research and development credits to sell these benefits for at least 80% of the value of the tax benefits to unaffiliated, profitable corporate taxpayers in the State of New Jersey. The Program is administered by The New Jersey Economic Development Authority and the New Jersey Department of the Treasury’s Division of Taxation. In January 2018, the Company completed the sale of NOLs totaling approximately $0.5 million. This amount is a current state tax benefit and is reflected in the statement of operations for the year ended December 31, 2018. The Company has now reached the maximum lifetime benefit of $15.0 million under the Program and will no longer be eligible to participate in the Program.

Restructuring Costs

12 Months Ended

Dec. 31, 2019

Restructuring Costs

Restructuring Costs

12. Restructuring Costs

In June 2018, the Company announced a reduction in its workforce, which resulted in the termination of several employees primarily from the Company’s commercial and clinical teams, representing approximately thirty percent of its employees. This workforce reduction, along with other reductions in planned operating expenses is designed to preserve cash while the Company pursued formal dispute resolution with the FDA for Twirla and determines a regulatory path forward for the resubmission of the Company’s NDA for Twirla.

In June 2018, the Company also announced that it had adopted a retention plan (the “Retention Plan”) to provide (i) cash retention payments to all remaining employees in order to induce such employees to remain employed by the Company through December 31, 2018 and (ii) stock option grants to all remaining employees in order to induce such employees to remain employed by the Company through December 31, 2019.

Each employee who participated in the Retention Plan and (i) remained continuously employed by the Company through December 31, 2018 or (ii) was terminated by the Company other than for cause (as defined in an applicable employment agreement, or, if no employment agreement exists, as determined by the Company in good faith) prior to December 31, 2018, was paid a lump-sum cash payment in an amount determined by the compensation committee (“Compensation Committee”) of the Company’s board of directors at the time of the adoption of the Retention Plan. If an eligible employee terminated service prior to December 31, 2018 for any reason other than termination of employment by the Company without cause, no such cash retention payment was made to the eligible employee. The total amount of the cash portion of the Retention Plan was approximately $0.6 million.

In addition, all remaining employees were granted a stock option to purchase the number of shares of common stock as approved by the Compensation Committee, with a per share exercise price of $0.58, representing the closing price of the Company’s common stock as reported by Nasdaq on the date the Retention Plan was approved by the Compensation Committee. Each option vested in four equal 25% installments on the following dates: (i) June 20, 2018, (ii) December 31, 2018, (iii) June 30, 2019 and (iv) December 31, 2019, subject to the employee's continuing service to the Company.

A summary of accrued restructuring costs, included as a component of accrued liabilities on the Company’s unaudited December 31, 2019 balance sheet is as follows:


	December 31, 2018		Charges		Payments		December 31, 2019

Accrued retention bonus		638		—		(638)		—
Total	$	638	$	—	$	(638)	$	—

2019 Retention Plan	12 Months Ended
2019 Retention Plan	Dec. 31, 2019
2019 Retention Plan
2019 Retention Plan	13. 2019 Retention Plan In July 2019, the Company adopted a retention plan (the “2019 Retention Plan”) for all employees (with the exception of the Chairman and Chief Executive Officer) in order to induce such employees to remain employed by the Company through at least the PDUFA goal date of November 16, 2019. Each employee who participates in the 2019 Retention Plan and remains continuously employed by the Company through the Approval shall be paid a lump-sum cash payment in an amount determined for each eligible employee by the Compensation Committee at the time of the adoption of the 2019 Retention Plan. If an eligible employee terminates employment prior to the Approval for any reason, no such retention payment shall be made to the eligible employee. The total amount of the cash portion of the 2019 Retention Plan is approximately $0.3 million. Given that the PDUFA goal date was extended to February 16, 2020 and the ultimate uncertainty of the approval of Twirla, the Company has not recorded compensation expense related to these potential cash awards for the year ended December 31, 2019. All employees (with the exception of the Chairman and Chief Executive Officer) who were employed by the Company as of July 3, 2019 were also granted a stock option to purchase the number of shares of common stock as approved by the Compensation Committee, with a per share exercise price of $1.48, representing the closing price of the Company’s common stock as reported by Nasdaq on the date of grant. Each option will vest in two equal 50% installments on the following dates (i) July 3, 2020 and (ii) December 31, 2020. In addition, the vesting for the annual stock option grant in January 2019 were amended for all employees holding such options who were employed on July 3, 2019 as follows: 50% of the option will vest on January 29, 2020, 25% on June 30, 2020 and the remaining 25% on December 31, 2020. The change in vesting schedule was approved by the Compensation Committee and did not have a material impact on the Company’s statement of operations.

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2019
Subsequent Event
Subsequent Event	15. Subsequent Event In February 2020, the Company entered into a Credit Agreement and Guaranty with Perceptive Credit Holdings III, LP, a related party, or Perceptive, for a senior secured term loan credit facility of up to $35 million, (the Perceptive Credit Agreement”). A first tranche of $5 million was funded on execution of the Perceptive Credit Agreement. A second tranche of $15 million was funded as a result of the approval of Twirla by the FDA. Another $15 million tranche will be available to the Company based on the achievement of certain revenue milestones. The facility will be interest only until the third anniversary of the closing date. As part of the Perceptive Credit Agreement, the Company issued Perceptive warrants to purchase 1,400,000 shares of Agile common stock. The per share exercise price for 700,000 shares is $3.74, which is equal to the 5-day volume weighted average exercise price ("5 Day VWAP") as of the trading day immediately prior to closing. The per share exercise price for the remaining 700,000 shares of Agile common stock is $4.67, which is 1.25 times the 5 Day VWAP.

Quarterly Data (Unaudited)

12 Months Ended

Dec. 31, 2019

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)

16. Quarterly Data (Unaudited)

The following tables summarize the quarterly results of operations for each of the quarters in 2019 and 2018. These quarterly results are unaudited, but in the opinion of management, have been prepared on the same basis as our audited financial information and include all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation of the information set forth herein (in thousands, except per share amounts).


	March 31,		June 30,		September 30,		December 31,
	2019		2019		2019		2019
Total revenue	$	—	$	—	$	—	$	—
Operating expenses	$	4,707	$	3,547	$	4,499	$	6,105
Net loss	$	(4,669)	$	(3,484)	$	(4,432)	$	(6,021)
Basic and diluted net loss per common share	$	(0.13)	$	(0.08)	$	(0.08)	$	(0.10)


	March 31,		June 30,		September 30,		December 31,
	2018		2018		2018		2018
Total revenue	$	—	$	—	$	—	$	—
Operating expenses	$	7,046	$	5,147	$	3,615	$	3,727
Net loss	$	(6,833)	$	(5,344)	$	(3,792)	$	(3,810)
Basic and diluted net loss per common share	$	(0.20)	$	(0.16)	$	(0.11)	$	(0.11)

The net loss and basic and diluted net loss per share for the quarter ended March 31, 2018 include a tax benefit of $0.5 million from the sale of New Jersey state NOLs. (see Note 11).

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Basis of Presentation

Use of Estimates

Risks and Uncertainties

Cash and Cash Equivalents

The Company maintains balances with financial institutions in excess of the Federal Deposit Insurance Corporation limit.

Fair Value of Financial Instruments

Other financial instruments, including accounts payable and accrued liabilities, are carried at cost, which approximates fair value given their short‑term nature.

Property and Equipment

Long-Lived Assets

Research and Development Expense

Deferred Financing Costs

Concentrations of Credit Risk

Warrants

Income Taxes

Stock-Based Compensation

Stock‑Based Compensation

Segment Information

Net Loss Per Share


	Year Ended December 31,
	2019	2018	2017
Common stock warrants	180,274	242,779	242,779
Unvested restricted stock units	—	147,554	264,361
Common stock options	7,192,357	5,687,901	3,805,305
Total	7,372,631	6,078,234	4,312,445

Recent Accounting Pronouncements

Management does not believe that any other recently issued, but not yet effective accounting pronouncements, if adopted, would have a material impact on the accompanying financial statements.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Schedule of outstanding potentially dilutive securities excluded from calculation of diluted net loss per share


	Year Ended December 31,
	2019	2018	2017
Common stock warrants	180,274	242,779	242,779
Unvested restricted stock units	—	147,554	264,361
Common stock options	7,192,357	5,687,901	3,805,305
Total	7,372,631	6,078,234	4,312,445

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Measurements

Schedule of financial instruments measured at fair value by level within the fair value hierarchy


	Level 1		Level 2		Level 3
2019
Assets:
Cash equivalents	$	34,444	$	—	$	—
Total assets at fair value	$	34,444	$	—	$	—


	Level 1		Level 2		Level 3
2018
Assets:
Cash equivalents	$	7,776	$	—	$	—
Total assets at fair value	$	7,776	$	—	$	—

Schedule of rollforward of the fair value of Level 3 warrants


Beginning balance at December 31, 2016	$	172
Change in fair value		(143)
Ending balance at December 31, 2017		29
Change in fair value		(29)
Ending balance at December 31, 2018		—
Change in fair value		—
Ending balance at December 31, 2019	$	—

Prepaid Expenses (Tables)

12 Months Ended

Dec. 31, 2019

Prepaid Expenses

Schedule of prepaid expenses


	December 31,
	2019		2018
Prepaid insurance	$	656	$	484
Other		184		123
Total prepaid expenses	$	840	$	607

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property and Equipment

Schedule of components of property and equipment


	December 31,
	2019		2018		Estimated Life
Office equipment	$	49	$	49	3 - 10 years
Computer equipment		179		175	3 years
Manufacturing equipment		14,203		14,061	5 years
		14,431		14,285
Less: accumulated depreciation		(387)		(369)
Property and equipment	$	14,044	$	13,916

Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Accrued Liabilities

Schedule of accrued liabilities


	December 31,
	2019		2018
Employee bonuses	$	1,437	$	621
Accrued retention bonus		—		638
Accrued professional fees and other		367		84
Total accrued liabilities	$	1,804	$	1,343

Leases (Tables)

12 Months Ended

Dec. 31, 2019

Leases

Maturity of lease liabilities

Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows:


2020	$	191
Total	$	191
Less: Interest		(19)
Present value of lease liability	$	172

Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2019

Equity Incentive Plans

Schedule of stock-based compensation expense


	Year Ended December 31,
	2019		2018		2017
Research and development	$	522	$	1,274	$	1,184
General and administrative		1,240		2,356		2,467
Total	$	1,762	$	3,630	$	3,651

Schedule of assumptions used to compute employee stock-based compensation


	2019					2018		2017
Risk-free interest rate	1.74	%	-	2.61	%	2.57	%	2.27	%
Expective volatility				65.0	%	70.0	%	73.9	%
Expected dividend yield				0	%	0	%	0	%
Expected life (in years)				6.25		6.25		6.25

Summary of options outstanding, vested and exercisable


				Weighted
		Weighted		Average
		Average		Remaining
		Exercise		Contractual	Aggregate
	Options	Price		Life (Years)	Intrinsic Value
Options outstanding at December 31, 2017	3,805,305		5.74	7.4
Options granted	2,230,000		1.96
Options exercised	—		—
Options cancelled/forfeited	(347,404)		4.19
Options outstanding at December 31, 2018	5,687,901		4.34	7.4
Options granted	2,805,600		1.18
Options exercised	(92,271)		1.78
Options cancelled/forfeited	(1,208,873)		2.70
Options outstanding at December 31, 2019	7,192,357		3.42	7.2	$	5,256
Options exercisable at December 31, 2019	4,396,577		4.60	6.1	$	2,228
Vested and expected to vest at December 31, 2019	7,192,357				$	5,256

Schedule of restricted stock activity



		Weighted Average		Aggregate
	Shares	Grant Date Fair Value		Intrinsic Value
Restricted stock units outstanding at December 31, 2017	264,361		3.16
Granted	108,254		3.46
Vested	(225,061)		3.39	$	370
Restricted stock units outstanding at December 31, 2018	147,554		3.03
Vested	(147,554)		3.03	$	129
Restricted stock units outstanding at December 31, 2019	—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes

Schedule of tax effects of temporary differences that give rise to significant portions of deferred tax assets


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	55,216	$	51,240
Research credit carryforward		7,609		6,904
Stock options and other		3,225		2,655
Total gross deferred tax assets		66,050		60,799
Valuation allowance for deferred tax assets		(66,050)		(60,799)
Net deferred tax assets	$	—	$	—

Schedule of reconciliation of U.S. statutory income tax rate to effective tax rate


	December 31,
	2019		2018		2017
Federal income tax at statutory rate	21.0	%	21.0	%	34.0	%
State income tax benefit, net of federal benefit	7.0	%	6.0	%	6.0	%
Research and development tax credits	4.0	%	3.0	%	3.0	%
Effect of tax rate changes	0.0	%	0.0	%	-94.0	%
Other	-4.0	%	-4.0	%	-1.0	%
Decrease (increase) to valuation allowance	-28.0	%	-24.0	%	52.0	%
Effective income tax rate	0.0	%	2.0	%	0.0	%

Restructuring Costs (Tables)

12 Months Ended

Dec. 31, 2019

Restructuring Costs

Summary of accrued restructuring costs, included as a component of accrued liabilities


	December 31, 2018		Charges		Payments		December 31, 2019

Accrued retention bonus		638		—		(638)		—
Total	$	638	$	—	$	(638)	$	—

Quarterly Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Data (Unaudited)

Summary of quarterly results of operations

These quarterly results are unaudited, but in the opinion of management, have been prepared on the same basis as our audited financial information and include all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation of the information set forth herein (in thousands, except per share amounts).


	March 31,		June 30,		September 30,		December 31,
	2019		2019		2019		2019
Total revenue	$	—	$	—	$	—	$	—
Operating expenses	$	4,707	$	3,547	$	4,499	$	6,105
Net loss	$	(4,669)	$	(3,484)	$	(4,432)	$	(6,021)
Basic and diluted net loss per common share	$	(0.13)	$	(0.08)	$	(0.08)	$	(0.10)


	March 31,		June 30,		September 30,		December 31,
	2018		2018		2018		2018
Total revenue	$	—	$	—	$	—	$	—
Operating expenses	$	7,046	$	5,147	$	3,615	$	3,727
Net loss	$	(6,833)	$	(5,344)	$	(3,792)	$	(3,810)
Basic and diluted net loss per common share	$	(0.20)	$	(0.16)	$	(0.11)	$	(0.11)

Organization and Description of Business (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 29, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations
Product revenue		$ 0
Accumulated deficit		(260,370)	$ (241,551)
Cash and cash equivalents		34,479	$ 7,851
Perceptive \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche One
Nature of Operations
Amount borrowed		5,000
Perceptive \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche Two
Nature of Operations
Amount borrowed		$ 15,000
Subsequent Event \| Perceptive \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement
Nature of Operations
Maximum borrowing capacity	$ 35,000
Subsequent Event \| Perceptive \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche One
Nature of Operations
Amount borrowed	5,000
Subsequent Event \| Perceptive \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche Two
Nature of Operations
Amount borrowed	$ 15,000

Summary of Significant Accounting Policies - Concentrations of Credit Risk (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Concentration of risk, financial assets
Financial instruments with off-balance sheet risk of accounting loss, assets	$ 0
Concentration risk, financial liabilities
Financial instruments with off-balance sheet risk of accounting loss, liabilities	$ 0

Summary of Significant Accounting Policies - Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2019	Dec. 14, 2019	Feb. 28, 2015
Additional Paid-in Capital
Warrants
Cumulative effect adjustment		$ 213
Accumulated Deficit
Warrants
Cumulative effect adjustment		$ (213)
Warrants \| Common stock warrants \| Hercules Capital, Inc.
Warrants
Number of warrants outstanding (in shares)		180,274		180,274
Exercise price of warrants (in dollars per share)		$ 5.89		$ 5.89
ASU 2017-11 \| Common stock warrants \| Oxford Finance LLC
Warrants
Common stock that can be purchased with warrants (in shares)			62,505
Number of warrants outstanding (in shares)		0
Exercise price of warrants (in dollars per share)			$ 6.00
ASU 2017-11 \| Adjustment \| Additional Paid-in Capital
Warrants
Cumulative effect adjustment	$ 213

Summary of Significant Accounting Policies - Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Anti-dilutive securities
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	7,372,631	6,078,234	4,312,445
Common stock warrants
Anti-dilutive securities
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	180,274	242,779	242,779
Restricted Stock Units
Anti-dilutive securities
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)		147,554	264,361
Common stock options
Anti-dilutive securities
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	7,192,357	5,687,901	3,805,305

Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
Recent Accounting Pronouncements
Lease liability	$ 172
ASU 2016-02 \| Adjustment
Recent Accounting Pronouncements
Right of use and other assets		$ 300
Lease liability		$ 300

Fair Value Measurements - Financial Instruments Measured at Fair Value by Hierarchy Level (Details) - Recurring - Level 1 - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Cash and cash equivalents	$ 34,444	$ 7,776
Total assets at fair value	$ 34,444	$ 7,776

Fair Value Measurements - Transfers Between Levels (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair value measurements
Asset transfers out of Level 1 into Level 2	$ 0	$ 0
Asset transfers out of Level 2 into Level 1	0	0
Asset transfers into (out of) Level 3	0	0
Liability transfers out of Level 1 into Level 2	0	0
Liability transfers out of Level 2 into Level 1	0	0
Liability transfers into (out of) Level 3	0	0
Common stock warrants \| Liabilities
Rollforward of the fair value of Level 3 warrants:
Beginning balance		29	$ 172
Change in fair value	0	$ (29)	(143)
Ending balance	$ 0		$ 29

Prepaid Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Prepaid Expenses
Prepaid insurance	$ 656	$ 484
Other	184	123
Total prepaid expenses	$ 840	$ 607

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property and Equipment
Property and equipment, gross	$ 14,431	$ 14,285
Less: accumulated depreciation	(387)	(369)
Property and equipment, net	14,044	13,916
Office equipment
Property and Equipment
Property and equipment, gross	$ 49	$ 49
Office equipment \| Minimum
Property and Equipment
Estimated Life (in years)	3 years	3 years
Office equipment \| Maximum
Property and Equipment
Estimated Life (in years)	10 years	10 years
Computer equipment
Property and Equipment
Property and equipment, gross	$ 179	$ 175
Estimated Life (in years)	3 years	3 years
Manufacturing equipment
Property and Equipment
Property and equipment, gross	$ 14,203	$ 14,061
Estimated Life (in years)	5 years	5 years
Manufacturing equipment in process of being constructed and qualified
Property and Equipment
Property and equipment, gross	$ 14,000	$ 13,900

Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities
Employee bonuses	$ 1,437	$ 621
Accrued retention bonus		638
Accrued professional fees and other	367	84
Total accrued liabilities	$ 1,804	$ 1,343

Leases - Summary (Details) $ in Thousands	12 Months Ended
Leases - Summary (Details) $ in Thousands	Dec. 31, 2019 USD ($) lease	Jan. 01, 2019 USD ($)
Leases
Lease liability	$ 172
Number of finance leases \| lease	0
Number of operating leases \| lease	1
Operating lease expense	$ 193
Operating lease expense information:
Cash paid for amounts included in measurement of lease liabilities	$ 152
Weighted-average remaining lease term (years)	11 months 1 day
Weighted-average discount rate	21.20%
ASU 2016-02 \| Adjustment
Leases
Lease assets		$ 300
Lease liability		$ 300

Leases - Maturity of lease liabilities (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Operating Leases
2020	$ 191
Total	191
Less: Interest	(19)
Present value of lease liability	$ 172

Loan and Security Agreement (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2015 USD ($) Y item $ / shares shares	Dec. 31, 2019 USD ($) installment $ / shares shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 01, 2018 USD ($)	Aug. 31, 2016 USD ($)
Warrants \| Option pricing model
Significant assumptions used in valuation of the Company's warrants
Life of treasury bonds	4 years
Warrants \| Common stock warrants \| Option pricing model \| Volatility
Significant assumptions used in valuation of the Company's warrants
Warrants, Measurement Input \| item	0.750
Warrants \| Common stock warrants \| Option pricing model \| Risk free interest rate
Significant assumptions used in valuation of the Company's warrants
Warrants, Measurement Input \| item	0.0122
Warrants \| Common stock warrants \| Option pricing model \| Strike price
Significant assumptions used in valuation of the Company's warrants
Warrants, Measurement Input \| item	5.89
Warrants \| Common stock warrants \| Option pricing model \| Share price
Significant assumptions used in valuation of the Company's warrants
Warrants, Measurement Input \| item	9.82
Warrants \| Common stock warrants \| Option pricing model \| Expected life
Significant assumptions used in valuation of the Company's warrants
Warrants, Measurement Input \| Y	4
Secured debt
Interest expense
Interest expense, including accretion of value of related warrants and amortization of deferred financing costs		$ 0	$ 1,100	$ 1,900
Secured debt \| Oxford Loan
Loan and Security Agreement
Repayment of existing debt	$ 15,500
Hercules Capital, Inc. \| Hercules Loan ("Term Loan") \| Right to participate in future equity financings \| Maximum
Loan and Security Agreement
Equity financings amount	$ 2,000
Hercules Capital, Inc. \| Warrants \| Common stock warrants
Loan and Security Agreement
Common stock that can be purchased with warrants (in shares) \| shares	180,274	180,274
Exercise price of warrants (in dollars per share) \| $ / shares	$ 5.89	$ 5.89
Hercules Capital, Inc. \| Additional Paid-in Capital
Loan and Security Agreement
Fair value of common stock warrants issued with debt financing	$ 1,200
Hercules Capital, Inc. \| Secured debt \| Hercules Loan ("Term Loan")
Loan and Security Agreement
Maximum borrowing capacity	25,000
Facility Fee						$ 165
Outstanding borrowings, current portion		$ 0	$ 0
Fixed interest rate (as a percent)		9.00%
Number of consecutive monthly principal installments \| installment		23
Final payment amount due					$ 611
Discount on debt	1,200
Hercules Capital, Inc. \| Secured debt \| Hercules Loan Tranche One
Loan and Security Agreement
Amount borrowed	$ 16,500
Hercules Capital, Inc. \| Secured debt \| Hercules Loan Tranche Two
Loan and Security Agreement
Additional amount available						$ 8,500
Hercules Capital, Inc. \| Secured debt \| Prime \| Hercules Loan ("Term Loan")
Loan and Security Agreement
Variable rate basis		Prime minus 4.25%
Variable interest rate margin (as a percent)		9.00%
Variable rate adjustment (as a percent)		(4.25%)

Stockholders' Equity - Amended and Restated Certificate of Incorporation (Details)	12 Months Ended
	Dec. 31, 2019 class shares	Dec. 31, 2018 shares
Stockholders' Equity
Common stock, authorized (in shares) \| shares	150,000,000	150,000,000
Preferred stock, authorized (in shares) \| shares	10,000,000
Board of Directors, number of classes \| class	3
Term of Board member	3 years
Number of classes elected at each annual meeting \| class	1
Minimum
Stockholders' Equity
Affirmative vote of all then-outstanding shares of capital stock for removal of directors (as a percent)	75.00%

Stockholders' Equity - Common Stock (Details) $ / shares in Units, $ in Thousands	1 Months Ended				2 Months Ended	12 Months Ended
	Aug. 31, 2019 USD ($) $ / shares shares	Aug. 31, 2017 USD ($) $ / shares shares	Feb. 29, 2016 $ / shares shares	Jan. 31, 2016 USD ($) shareholder $ / shares shares	Feb. 29, 2016 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2017 USD ($) shares	Nov. 08, 2019 USD ($)	Jan. 23, 2019 USD ($)	Nov. 02, 2018 USD ($)	Jun. 19, 2015 USD ($)
2018 Shelf Registration Statement
Sale of stock
Aggregate amount of securities issuable										$ 100,000
2015 Shelf Registration Statement
Sale of stock
Aggregate amount of securities issuable											$ 150,000
2016 Public Offering \| Stockholders affiliated with members of board of directors
Sale of stock
Sale of Stock, Number of Stockholders Affiliated with Members of Board of Directors Who Purchased Shares in Transaction \| shareholder				1
2016 Public Offering \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares				5,511,812	6,338,583
Share price (in dollars per share) \| $ / shares				$ 6.35
Proceeds from sales or issuance of common stock, net of offering costs					$ 37,500
2016 Public Offering \| Common Stock \| Stockholders affiliated with members of board of directors
Sale of stock
Issuance of common stock (in shares) \| shares				393,700
Proceeds from sales or issuance of common stock, net of offering costs				$ 2,500
2017 Public Offering \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares		5,333,334
Share price (in dollars per share) \| $ / shares		$ 3.75
Proceeds from sales or issuance of common stock, net of offering costs		$ 18,500
Private Placement \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares						8,426,750
Underwriter purchase option \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares			826,771
Share price (in dollars per share) \| $ / shares			$ 6.35		$ 6.35
At-the-market sales
Sale of stock
Proceeds from sales or issuance of common stock, net of offering costs						$ 42,251	$ 18,535
At-the-market sales \| Maximum
Sale of stock
Authorized value for shares issuance								$ 20,000	$ 10,000
At-the-market sales \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares						12,242,436
At Market Sales on January 23
Sale of stock
Proceeds from sales or issuance of common stock, net of offering costs						$ 2,500
At Market Sales on January 23 \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares						1,801,528
At Market Sales on November 8
Sale of stock
Proceeds from sales or issuance of common stock, net of offering costs						$ 19,300
At Market Sales on November 8 \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares						10,440,908
Public offering \| Common Stock
Sale of stock
Issuance of common stock (in shares) \| shares	14,526,315					14,526,315	5,333,334
Share price (in dollars per share) \| $ / shares	$ 0.95
Proceeds from sales or issuance of common stock, net of offering costs	$ 12,700

Equity Incentive Plans - Stock Options Summary (Details) - Common stock options	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Minimum
Equity Incentive Plans
Exercise prices of options granted through the end of the year (in dollars per share)	$ 0.58
Maximum
Equity Incentive Plans
Exercise prices of options granted through the end of the year (in dollars per share)	$ 10.75
1997 Plan and 2008 Plan
Equity Incentive Plans
Expiration period	10 years
Vesting period	4 years
2014 Equity Incentive Plan
Equity Incentive Plans
Shares available for grant \| shares	2,170,175

Equity Incentive Plans - Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Incentive Plans
Total stock-based compensation expense	$ 1,762	$ 3,630	$ 3,651
Assumptions used to compute employee stock based compensation under the Black-Scholes option pricing model
Risk-free interest rate (as a percent)	2.61%	2.57%	2.27%
Expective volatility (as a percent)	65.00%	70.00%	73.90%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%
Expected life (in years)	6 years 3 months	6 years 3 months	6 years 3 months
Minimum
Assumptions used to compute employee stock based compensation under the Black-Scholes option pricing model
Risk-free interest rate (as a percent)	1.74%
Common stock options
Equity Incentive Plans
Total stock-based compensation expense	$ 1,762	$ 3,630	$ 3,651
Unrecorded deferred stock-based compensation
Unrecorded deferred stock-based compensation balance related to stock options	$ 1,900
Weighted-average amortization period over which cost is expected to be recognized	1 year 4 months 24 days
Weighted average grant date fair value of options granted (in dollars per share)	$ 0.59
Common stock options \| Research and development
Equity Incentive Plans
Total stock-based compensation expense	$ 522	1,274	1,184
Common stock options \| General and administrative
Equity Incentive Plans
Total stock-based compensation expense	$ 1,240	$ 2,356	$ 2,467

Equity Incentive Plans - Stock Option Activity (Details) - Common stock options - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Options
Options outstanding at beginning of year (in shares)	5,687,901	3,805,305
Options granted (in shares)	2,805,600	2,230,000
Options exercised (in shares)	(92,271)	0
Options cancelled/forfeited (in shares)	(1,208,873)	(347,404)
Options outstanding at end of year (in shares)	7,192,357	5,687,901	3,805,305
Options exercisable at end of year (in shares)	4,396,577
Vested and expected to vest at end of year (in shares)	7,192,357
Weighted Average Exercise Price
Options outstanding at beginning of year (in dollars per share)	$ 4.34	$ 5.74
Options granted (in dollars per share)	1.18	1.96
Options exercised (in dollars per share)	1.78	0.00
Options cancelled/forfeited (in dollars per share)	2.70	4.19
Options outstanding at end of year (in dollars per share)	3.42	$ 4.34	$ 5.74
Options exercisable at end of year (in dollars per share)	4.60
Vested and expected to vest at end of year (in dollars per share)	$ 0.00
Weighted Average Remaining Contractual Life (Years)
Options outstanding	7 years 2 months 12 days	7 years 4 months 24 days	7 years 4 months 24 days
Options exercisable	6 years 1 month 6 days
Aggregate Intrinsic Value
Options outstanding at the end of the year (in dollars)	$ 5,256
Options exercisable at the end of the year (in dollars)	2,228
Vested and expected to vest at end of year	$ 5,256
Estimated stock price (in dollars per share)	$ 2.50

Equity Incentive Plans - Restricted Stock (Details) - Restricted Stock Units - USD ($)	1 Months Ended		12 Months Ended
	Feb. 28, 2018	Feb. 28, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares
Restricted stock outstanding at beginning of year (in shares)			147,554	264,361
Granted (in shares)				108,254
Vested (in shares)			(147,554)	(225,061)
Restricted stock outstanding at end of year (in shares)			0	147,554	264,361
Weighted Average Grant Date Fair Value
Restricted stock outstanding at beginning of year (in dollars per share)			$ 3.03	$ 3.16
Granted (in dollars per share)				3.46
Vested (in dollars per share)			3.03	3.39
Restricted stock outstanding at end of year (in dollars per share)			$ 0.00	$ 3.03	$ 3.16
Aggregate Intrinsic Value
Intrinsic value of vested shares			$ 129	$ 370
Employee
Shares
Granted (in shares)						50,000
Vested (in shares)	(16,667)	(16,667)				(16,666)
Executive officers
Shares
Granted (in shares)				108,254	247,694
Vesting period				1 year	2 years
Directors
Shares
Vesting period					1 year

Equity Incentive Plans - Performance Based Restricted Stock Awards (Details) - 2014 Equity Incentive Plan - Performance Units - Executive officers - shares	1 Months Ended	12 Months Ended
	Jan. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Equity Incentive Plans
Shares granted	365,000	50,000	260,000
Shares outstanding		315,000		315,000

Income Taxes - Summary (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes - Summary (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Corporate tax rate (as a percent)	21.00%	21.00%	34.00%
Federal \| Net Operating Losses
Income Taxes
Net operating loss carryforwards	$ 231.5		$ 198.9
Indefinite net operating loss carryforward	32.5	$ 32.5
Federal \| Research and Development
Income Taxes
Tax credit carryforwards	6.3
State \| Net Operating Losses
Income Taxes
Net operating loss carryforwards	92.4
State \| Research and Development
Income Taxes
Tax credit carryforwards	$ 1.6

Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 55,216	$ 51,240
Research credit carryforward	7,609	6,904
Stock options and other	3,225	2,655
Total gross deferred tax assets	66,050	60,799
Valuation allowance for deferred tax assets	(66,050)	(60,799)
Net deferred tax assets	0	0
Valuation allowance
Increase (decrease) in the valuation allowance	$ 5,300	$ 4,800

Income Taxes - Reconciliation of U.S. Statutory Income Tax Rate to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the U.S. statutory income tax rate to the Company's effective tax rate
Federal income tax at statutory rate (as a percent)	21.00%	21.00%	34.00%
State income tax benefit, net of federal benefit (as a percent)	7.00%	6.00%	6.00%
Research and development tax credits (as a percent)	4.00%	3.00%	3.00%
Effect of tax rate changes (as a percent)	0.00%	0.00%	(94.00%)
Other (as a percent)	(4.00%)	(4.00%)	(1.00%)
Decrease (increase) to valuation allowance (as a percent)	(28.00%)	(24.00%)	52.00%
Effective income tax rate (as a percent)	0.00%	2.00%	0.00%

Income Taxes - Sale of New Jersey Net Operating Losses (Details) - USD ($) $ in Millions	1 Months Ended
	Jan. 31, 2018	Dec. 31, 2019
Technology Business Tax Certificate Program \| New Jersey
Sale of New Jersey Net Operating Losses
NOLs	$ 0.5
Maximum lifetime benefit under the Program	$ 15.0
Technology Business Tax Certificate Program \| New Jersey \| Minimum
Sale of New Jersey Net Operating Losses
Allowable sale of unused tax benefits as a percentage of total value	80.00%
Net Operating Losses \| State
Sale of New Jersey Net Operating Losses
NOLs		$ 92.4
Research and Development \| State
Sale of New Jersey Net Operating Losses
Tax credits		$ 1.6

Restructuring Costs (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2019 USD ($) installment $ / shares	Dec. 31, 2018 USD ($)
Restructuring Costs
Reduction in workforce (as a percent)	30.00%
Restructuring Costs
Beginning balance		$ 638
Charges		0	$ 1,019
Payments		(638)
Ending balance		0	638
Accrued retention bonus
Restructuring Costs
Beginning balance		638
Charges		0
Payments		(638)
Ending balance		0	$ 638
Retention Plan
Restructuring Costs
Cash portion of the retention plan		$ 600
Stock option exercise price (in dollars per share) \| $ / shares		$ 0.58
Number of installments for option to vest \| installment		4
Retention Plan \| Vesting on June 20, 2018
Restructuring Costs
Percentage of options to vest		25.00%
Retention Plan \| Vesting on December 31, 2018
Restructuring Costs
Percentage of options to vest		25.00%
Retention Plan \| Vesting on June 30, 2019
Restructuring Costs
Percentage of options to vest		25.00%
Retention Plan \| Vesting on December 31, 2019
Restructuring Costs
Percentage of options to vest		25.00%

2019 Retention Plan (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Jul. 03, 2019	Dec. 31, 2019 installment $ / shares	Jul. 31, 2019 USD ($)
Options granted In January 2019 \| Vesting on January 29, 2020
2019 Retention Plan
Percentage of options to vest	50.00%
Options granted In January 2019 \| Vesting on June 30, 2020
2019 Retention Plan
Percentage of options to vest	25.00%
Options granted In January 2019 \| Vesting on December 31, 2020
2019 Retention Plan
Percentage of options to vest	25.00%
Options granted in July 2019
2019 Retention Plan
Stock option exercise price (in dollars per share) \| $ / shares		$ 1.48
Number of installments for option to vest \| installment		2
Options granted in July 2019 \| Vesting on July 3, 2020
2019 Retention Plan
Percentage of options to vest		50.00%
Options granted in July 2019 \| Vesting on December 31, 2020
2019 Retention Plan
Percentage of options to vest		50.00%
2019 Retention Plan
2019 Retention Plan
Cash portion of the retention plan \| $			$ 0.3

Subsequent Event (Details) - Perceptive $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Feb. 29, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)
Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche One
Subsequent Event [Line Items]
Amount borrowed		$ 5.0
Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche Two
Subsequent Event [Line Items]
Amount borrowed		$ 15.0
Subsequent Event \| Perceptive Credit Agreement \| Perceptive Warrants
Subsequent Event [Line Items]
Common stock that can be purchased with warrants (in shares) \| shares	1,400,000
Subsequent Event \| Perceptive Credit Agreement \| First Seven Lakhs Shares
Subsequent Event [Line Items]
Exercise price of warrants (in dollars per share) \| $ / shares	$ 3.74
Common stock that can be purchased with warrants (in shares) \| shares	700,000
Volume weighted average exercise price period	5 days
Subsequent Event \| Perceptive Credit Agreement \| Remaining Seven Lakhs Shares
Subsequent Event [Line Items]
Exercise price of warrants (in dollars per share) \| $ / shares	$ 4.67
Common stock that can be purchased with warrants (in shares) \| shares	700,000
Number of times on five day volume weighted average exercise price	1.25
Subsequent Event \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 35.0
Subsequent Event \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche One
Subsequent Event [Line Items]
Amount borrowed	5.0
Subsequent Event \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche Two
Subsequent Event [Line Items]
Amount borrowed	15.0
Subsequent Event \| Senior secured delayed draw term loan facility \| Perceptive Credit Agreement, Tranche Three
Subsequent Event [Line Items]
Additional amount available	$ 15.0

Quarterly Data (Unaudited) - Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Data (Unaudited)
Total revenue									$ 0
Operating expenses	$ 6,105	$ 4,499	$ 3,547	$ 4,707	$ 3,727	$ 3,615	$ 5,147	$ 7,046	18,858	$ 19,535	$ 26,811
Net loss	$ (6,021)	$ (4,432)	$ (3,484)	$ (4,669)	$ (3,810)	$ (3,792)	$ (5,344)	$ (6,833)	$ (18,606)	$ (19,779)	$ (28,304)
Basic and diluted net loss per common share (in dollars per share)	$ (0.10)	$ (0.08)	$ (0.08)	$ (0.13)	$ (0.11)	$ (0.11)	$ (0.16)	$ (0.20)	$ (0.38)	$ (0.58)	$ (0.91)

- Definition

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

+ References + Details

Quarterly Data (Unaudited) - Tax Benefit from Sale of New Jersey State Net Operating Losses (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
New Jersey \| Technology Business Tax Certificate Program
Sale of New Jersey Net Operating Losses
Tax benefit	$ 0.5

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2019
Commitments and Contingencies
Commitments and Contingencies	14. Commitments and Contingencies The Company records a provision for contingent losses when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. An unfavorable outcome to any legal matter, if material, could have an adverse effect on the Company's operations or its financial position. As of December 31, 2019, the Company has not recorded a provision for any contingent losses.

Summary of Significant Accounting Policies - Income Taxes (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Uncertainty in tax positions
Uncertain tax positions	$ 0

Summary of Significant Accounting Policies - Segment Information (Details)	12 Months Ended
	Dec. 31, 2019 segment
Segment Information
Number of operating segments	1
Number of reporting segments	1