NVN Liquidation (NOVNQ) 10-K 24 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 18, 2020	Jun. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	NOVN
Title of 12(b) Security	Common Stock, $0.0001 par value
Entity Registrant Name	NOVAN, INC.
Entity Central Index Key	0001467154
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Shell Company	false
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding (in shares)		27,434,800
Entity Public Float			$ 57

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 13,711	$ 8,194
Contracts and grants receivable	419	0
Deferred offering costs	49	49
Prepaid expenses and other current assets	1,545	1,107
Total current assets	15,724	9,350
Restricted cash	540	539
Intangible assets	75	75
Other assets	419	530
Property and equipment, net	10,506	15,868
Right-of-use lease assets	1,833	0
Total assets	29,097	26,362
Current liabilities:
Accounts payable	1,602	1,250
Accrued compensation	437	1,467
Accrued outside research and development services	1,013	563
Accrued legal and professional fees	616	498
Other accrued expenses	553	871
Deferred revenue, current portion	4,428	4,401
Research and development service obligation liability, current portion	3,088	0
Lease liabilities, current portion	1,162	11
Total current liabilities	12,899	9,061
Deferred revenue, net of current portion	7,076	2,566
Lease liabilities, net of current portion	5,100	10
Warrant liability	1,504	1,240
Research and development service obligation liability, net of current portion	727	0
Research and development funding arrangement liability, related party	25,000	0
Other long-term liabilities	578	289
Facility financing obligation	0	7,998
Total liabilities	52,884	21,164
Commitments and contingencies (Note 8)
Stockholders’ equity (deficit)
Common stock issued	3	3
Additional paid-in-capital	180,047	177,677
Treasury stock at cost	(155)	(155)
Accumulated deficit	(203,682)	(172,327)
Total stockholders' (deficit) equity	(23,787)	5,198
Total liabilities and stockholders’ (deficit) equity	$ 29,097	$ 26,362

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock outstanding	$ 3	$ 3
Common stock, par value (in USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	26,744,300	26,066,235
Common stock, shares outstanding (in shares)	26,734,800	26,056,735
Treasury stock, shares (in shares)	9,500	9,500

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total revenue	$ 4,896	$ 5,991
Operating expenses:
Research and development	25,172	23,045
General and administrative	10,412	11,507
Total operating expenses	35,584	34,552
Operating loss	(30,688)	(28,561)
Other income (expense), net:
Interest income	177	297
Interest expense	(2)	(1,047)
Change in fair value of warrant liability	(264)	16,566
Other income, net	136	72
Total other income (expense), net	47	15,888
Net loss	(30,641)	(12,673)
Comprehensive loss	$ (30,641)	$ (12,673)
Net loss per share, basic and diluted (in USD per share)	$ (1.17)	$ (0.49)
Weighted-average common shares outstanding, basic and diluted (in shares)	26,254,119	25,795,721
License and collaboration revenue
Total revenue	$ 4,477	$ 5,982
Government research contracts and grants revenue
Total revenue	419	0
Research and development services revenue
Total revenue	$ 0	$ 9

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit
Beginning balance, shares (in shares) at Dec. 31, 2017		16,005,408
Beginning balance at Dec. 31, 2017	$ (1,716)	$ 2	$ 158,091	$ (155)	$ (159,654)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	$ 2,139		2,139
Exercise of stock options (in shares)	51,327	51,327
Exercise of stock options	$ 60		60
Liability-based awards reclassified to additional paid-in capital	0
Common stock issued during period (in shares)		10,000,000
Common stock issued during period	17,388	$ 1	17,387
Net loss	(12,673)				(12,673)
Ending balance, in shares (in shares) at Dec. 31, 2018		26,056,735
Ending balance at Dec. 31, 2018	5,198	$ 3	177,677	(155)	(172,327)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	$ 1,188		1,188
Exercise of stock options (in shares)	32,443	32,443
Exercise of stock options	$ 69		69
Liability-based awards reclassified to additional paid-in capital	366		366
Common stock issued during period (in shares)		645,622
Common stock issued during period	747	$ 0	747
Net loss	(30,641)				(30,641)
Ending balance, in shares (in shares) at Dec. 31, 2019		26,734,800
Ending balance at Dec. 31, 2019	$ (23,787)	$ 3	$ 180,047	$ (155)	$ (203,682)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flow from operating activities:
Net loss	$ (30,641)	$ (12,673)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,033	1,664
Share-based compensation	1,838	2,204
Loss on disposal and write-offs of property and equipment	36	154
Change in fair value of warrant liability	264	(16,566)
Contracts and grants receivable	(419)	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(438)	(224)
Accounts payable	352	777
Accrued compensation	(1,030)	(701)
Accrued outside research and development services	450	(829)
Accrued legal and professional fees	159	132
Other accrued expenses	(397)	(615)
Deferred revenue	4,537	(1,610)
Advanced payment for research and development service obligation	12,000	0
Research and development service obligation liabilities	(8,185)	0
Other long-term assets and liabilities	(435)	(338)
Net cash used in operating activities	(19,876)	(28,625)
Cash flow from investing activities:
Purchases of property and equipment	(422)	(1,107)
Proceeds from the sale of property and equipment	0	49
Net cash used in investing activities	(422)	(1,058)
Cash flow from financing activities:
Proceeds from research and development funding arrangement	25,000	0
Proceeds from issuance of common stock, net of underwriting fees and commissions	747	35,625
Payments related to public offering costs	0	(321)
Proceeds from exercise of stock options	69	60
Payments on capital lease obligation	0	(11)
Net cash provided by financing activities	25,816	35,353
Net increase in cash, cash equivalents and restricted cash	5,518	5,670
Cash, cash equivalents and restricted cash as of beginning of period	8,733	3,063
Cash, cash equivalents and restricted cash as of end of period	14,251	8,733
Supplemental disclosure of cash flow information:
Cash paid for interest	2	1,043
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property and equipment with accounts payable and accrued expenses	79	0
Right of use assets obtained in exchange for lease liabilities	1,827	0
Liability-based awards reclassified to additional paid-in capital	366	0
Common stock issued for payment of commitment fee	750	0
Deferred offering costs reclassified to additional paid-in capital	0	431
Reconciliation to consolidated balance sheets:
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 14,251	$ 8,733

Organization and Significant Ac

Organization and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Organization and Significant Accounting Policies	Organization and Significant Accounting Policies Business Description and Basis of Presentation Novan, Inc. (“Novan” and together with its subsidiaries, the “Company”), is a North Carolina-based clinical development-stage biotechnology company focused on leveraging nitric oxide’s naturally occurring anti-viral, anti-bacterial, anti-fungal and immunomodulatory mechanisms of action to treat a range of diseases with significant unmet needs. Novan was incorporated in January 2006 under the state laws of Delaware. Its wholly-owned subsidiary, Novan Therapeutics, LLC was organized in 2015 under the state laws of North Carolina. On March 14, 2019, the Company completed registration of a wholly-owned Ireland-based subsidiary, Novan Therapeutics, Limited. The accompanying consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). Additionally, each of the two reports of the Company’s independent registered public accounting firm on the Company’s consolidated financial statements as of and for the years ended December 31, 2019 and December 31, 2018 , respectively, included an explanatory paragraph indicating that there is substantial doubt about the Company’s ability to continue as a going concern. Basis of Consolidation The accompanying consolidated financial statements reflect the operations of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Liquidity and Ability to Continue as a Going Concern The Company’s consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The accompanying consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from uncertainty related to the Company’s ability to continue as a going concern. The Company has evaluated principal conditions and events that may raise substantial doubt about its ability to continue as a going concern within one year from the date that these financial statements are issued. The Company identified the following conditions: • The Company has reported a net loss in all fiscal periods since inception and, as of December 31, 2019 , the Company had an accumulated deficit of $203,682 . • As described in Note 9—Stockholders’ Equity, in August 2019 the Company entered into a common stock purchase agreement (the “Aspire Common Stock Purchase Agreement”) with Aspire Capital Fund, LLC, (“Aspire Capital”) which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $25,000 of shares of the Company’s common stock at the Company’s request from time to time during the 30 -month term of the Aspire Common Stock Purchase Agreement. The aggregate amount available to the Company through sales of common stock under the Aspire Common Stock Purchase Agreement is subject to certain limitations including, but not limited to: (i) the number of shares that may be sold will be limited to 5,211,339 shares, representing 19.99% of the Company’s outstanding shares of common stock on August 30, 2019, if the average price paid for all shares issued under the agreement is less than $2.17 ; and (ii) on any purchase date, the closing sale price of the Company’s common stock must be greater than or equal to $0.25 . As of December 31, 2019, the Company had sold 300,000 shares of common stock at an average price of $2.49 per share under the Aspire Common Stock Purchase Agreement. As of January 31, 2020, the Company had sold an aggregate of 1,000,000 shares of common stock at an average price of $1.19 per share under the Aspire Common Stock Purchase Agreement. These amounts, combined with the 345,622 shares issued as part of the commitment fee related to the agreement’s execution, leads to a total of 1,345,622 shares issued to Aspire Capital under the Aspire Common Stock Purchase Agreement as of January 31, 2020. • As of December 31, 2019 , the Company had a total cash and cash equivalents balance of $13,711 . The Company has concluded that the prevailing conditions and ongoing liquidity risks faced by the Company raise substantial doubt about its ability to continue as a going concern. Based on its current cash flow forecast, the Company does not currently have sufficient cash and cash equivalents to continue its business operations beyond the early part of the second quarter of 2020 . Therefore, the Company will need to raise substantial additional funding by the early part of the second quarter of 2020 in order to continue its operating activities and make further advancements in its drug development programs. There can be no assurance that the Company will be able to obtain additional capital on terms acceptable to the Company, on a timely basis or at all. The failure of the Company to obtain sufficient funds on acceptable terms could have a material adverse effect on the Company’s business and cause the Company to alter or reduce its planned operating activities, including but not limited to delaying, reducing, terminating or eliminating planned product candidate development activities, to conserve its cash and cash equivalents. The Company needs and intends to secure additional capital from non-dilutive sources, including partnerships, collaborations, licensing, grants or other strategic relationships, or through equity or debt financings. Any issuance of equity or debt that could be convertible into equity would result in significant dilution to our existing stockholders. Alternatively, the Company may seek to engage in one or more potential transactions, such as the sale of the Company, or sale or divestiture of some of its assets, such as a sale of its dermatology platform assets, but there can be no assurance that the Company will be able to enter into such a transaction or transactions on a timely basis or at all on terms that are favorable to the Company. Under these circumstances, the Company may instead determine to dissolve and liquidate its assets or seek protection under the bankruptcy laws. If the Company decides to dissolve and liquidate its assets or to seek protection under the bankruptcy laws, it is unclear to what extent the Company will be able to pay its obligations, and, accordingly, it is further unclear whether and to what extent any resources will be available for distributions to stockholders. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from these estimates. Cash and Cash Equivalents The Company considers all highly liquid instruments purchased with a maturity of three months or less to be cash equivalents. Cash and cash equivalents include deposits and money market accounts. Restricted Cash Restricted cash as of December 31, 2019 and 2018 includes funds maintained in a separate deposit account to secure a letter of credit for the benefit of the lessor of facility space leased by the Company. See Note 6—Research and Development Arrangements for a discussion of the restricted cash presentation associated with the Ligand Funding Agreement during interim reporting periods in 2019. Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of cash and cash equivalents. The Company places its cash and cash equivalents with financial institutions and these deposits may at times be in excess of insured limits. Contracts and Grants Receivable The Company carries its contracts and grants receivable net of an allowance for doubtful accounts. All receivables or portions thereof that are deemed to be uncollectible or that require excessive collection costs are written off to the allowance for doubtful accounts when it is probable that the receivable is unrecoverable. The Company actively reviews and evaluates its contracts and grants receivable, but no allowance for doubtful accounts has been considered necessary as of December 31, 2019 . Actual results could differ from the estimates that were used. The Company did not have a contracts and grants receivable balance as of December 31, 2018. Intangible Assets Intangible assets represent the cost to obtain and register the Company’s internet domain. Indefinite-lived intangible assets are not amortized and are assessed for impairment at least annually. Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives as follows: Computer and office equipment 3 years Furniture and fixtures 5-7 years Laboratory equipment 7 years Building asset under facility lease 25 years Leasehold improvements are amortized over the shorter of the life of the lease or the useful life of the improvements. Expenditures for maintenance and repairs are expensed as incurred. Improvements and betterments that add new functionality or extend the useful life of an asset are capitalized. Intellectual Property The Company’s policy is to file patent applications to protect technology, inventions and improvements that are considered important to its business. Patent positions, including those of the Company, are uncertain and involve complex legal and factual questions for which important legal principles are largely unresolved. Due to the uncertainty of future value to be realized from the expenses incurred in developing the Company’s intellectual property, the cost of filing, prosecuting and maintaining internally developed patents are expensed as general and administrative costs as incurred. Leases The Company leases office space and certain equipment under non-cancelable lease agreements. Prior to January 1, 2019, the Company applied the accounting guidance in ASC 840, Leases , to its lease agreements. The leases were reviewed for classification as operating or capital leases. For operating leases, rent was recognized on a straight-line basis over the lease period. For capital leases, the Company recorded the leased asset with a corresponding liability and amortized the asset over the lease term. Payments were recorded as reductions to the liability with an appropriate interest charge recorded based on the then-outstanding remaining liability. Beginning January 1, 2019, the Company applies the accounting guidance in ASC 842, Leases. As such, the Company assesses all arrangements, that convey the right to control the use of property, plant and equipment, at inception, to determine if it is, or contains, a lease based on the unique facts and circumstances present in that arrangement. For those leases identified, the Company determines the lease classification, recognition, and measurement at the lease commencement date. For arrangements that contain a lease the Company: (i) identifies lease and non-lease components; (ii) determines the consideration in the contract; (iii) determines whether the lease is an operating or financing lease; and (iv) recognizes lease Right of Use (“ROU”) assets and corresponding lease liabilities. Lease liabilities are recorded based on the present value of lease payments over the expected lease term. The corresponding ROU asset is measured from the initial lease liability, adjusted by (i) accrued or prepaid rents; (ii) remaining unamortized initial direct costs and lease incentives; and (iii) any impairments of the ROU asset. The interest rate implicit in the Company’s lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized for an amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no impairments of long-lived assets during the years ended December 31, 2019 and 2018 . Deferred Offering Costs Deferred offering costs consist of legal, accounting, filing and other fees directly related to offerings or the Company’s shelf registration. These costs are offset against proceeds from each offering as applicable. Offering costs incurred prior to the completion of an offering are initially capitalized as assets, evaluated each period for likelihood of completion and subsequently reclassified to additional paid-in capital upon completion of the offering. Deferred costs associated with the shelf registration will be reclassified to additional paid in capital on a pro-rata basis in the event the Company completes an offering under the shelf registration, with any remaining deferred offering costs charged to general and administrative expense at the end of the three -year life of the shelf registration. Revenue Recognition Effective January 1, 2018, the Company adopted ASC Topic 606, Revenue from Contracts with Customers , using the full retrospective transition method. To determine revenue recognition for arrangements that the Company determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contracts with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Upon occurrence of a contract modification, the Company conducts an evaluation pursuant to the modification framework in Topic 606 to determine the appropriate revenue recognition. The framework centers around key questions, including (i) whether the modification adds additional goods and services, (ii) whether those goods and services are distinct, and (iii) whether the contract price increases by an amount that reflects the standalone selling price for the new goods or services. The resulting conclusions will determine whether the modification is treated as a separate, standalone contract or if it is combined with the original contract and accounted for in that manner. In addition, some modifications are accounted for on a prospective basis and others on a cumulative catch-up basis. The Company’s agreements may contain some or all the following types of provisions or payments: Licenses of Intellectual Property : If the license of the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the estimated performance period and the appropriate method of measuring progress during the performance period for purposes of recognizing revenue. The Company re-evaluates the estimated performance period and measure of progress each reporting period and, if necessary, adjusts related revenue recognition accordingly. Milestone Payments : At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license and collaboration revenue and earnings in the period of adjustment. Manufacturing Supply Services : Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to the licensee and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in license and collaboration revenue when the customer obtains control of the goods, which is upon delivery. Royalties : For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. The Company’s revenue also includes research revenue earned under contracts and grants with Federal government agencies, which relates to the research and development of its nitric oxide platform. Government research contracts and grants revenue . Under the terms of the contracts and grants awarded, the Company is entitled to receive reimbursement of its allowable direct expenses, allocated overhead, general and administrative expenses and payment of other specified amounts. Revenues from development and support activities under government research contracts and grants are recorded in the period in which the related costs are incurred. Associated expenses are recognized when incurred as research and development expense. Revenue recognized in excess of amounts collected from funding sources are recorded as contracts and grants receivable. Any of the funding sources may, at their discretion, request reimbursement for expenses or return of funds, or both, as a result of noncompliance by the Company with the terms of the grants. No reimbursement of expenses or return of funds has been requested or made since inception of the contracts and grants. See Note 5—Revenue Recognition for information regarding two government grants the Company received in the third quarter of 2019. Research and Development Expenses Research and development expenses include all direct and indirect development costs incurred for the development of the Company’s drug candidates. These expenses include salaries and related costs, including share-based compensation and travel costs for research and development personnel, allocated facility costs, laboratory and manufacturing materials and supplies, consulting fees, product development, preclinical studies, clinical trial costs, licensing fees and milestone payments under license agreements and other fees and costs related to the development of drug candidates. The cost of tangible and intangible assets that are acquired for use on a particular research and development project, have no alternative future uses, and are not required to be capitalized in accordance with the Company’s capitalization policy, are expensed as research and development costs as incurred. Accrued Outside Research and Development Accruals The Company is required to estimate its expenses resulting from its obligations under contracts with clinical research organizations, clinical site agreements, vendors, and consultants in connection with conducting clinical trials and preclinical development. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate development and clinical trial expenses in its financial statements by matching those expenses with the period in which the services and efforts are expended. For clinical trials, the Company accounts for these expenses according to the progress of the trial as measured by actual hours expended by contract research organization personnel, investigator performance or completion of specific tasks, patient progression, or timing of various aspects of the trial. During the course of a clinical trial, the Company adjusts its rate of clinical trial expense recognition if actual results differ from its estimates. The Company utilizes judgment and experience to estimate its accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of status and timing of services performed relative to the actual status and timing of services performed may vary and may result in increases or decreases in research and development expenses in future periods when the actual results become known. For preclinical development services performed by outside service providers, the Company determines accrual estimates through financial models, considering development progress data received from outside service providers and discussions with applicable Company and service provider personnel. Fair Value of Financial Instruments The carrying values of cash equivalents, accounts payable and accrued liabilities as of December 31, 2019 and 2018 approximated their fair values due to the short-term nature of these items. For warrants that are issued or modified and there is a deemed possibility that the Company may have to settle them in cash, it records the fair value of the warrants at the initial measurement date, or date of issuance, and each balance sheet date thereafter. Changes in the estimated fair value of the warrants are recognized as a non-cash gain or loss on the consolidated statements of operations and comprehensive loss. The Company has categorized its financial instruments, based on the priority of the inputs used to value the investments, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and lowest priority to unobservable inputs (Level 3). If the inputs used to measure the investments fall within different levels of the hierarchy, the categorization is based on the lowest level input that is significant to the fair value measurement of the investment. Financial instruments recorded in the accompanying consolidated balance sheets are categorized based on the inputs to valuation techniques as follows: Level 1 - Observable inputs that reflect unadjusted quoted market prices for identical assets or liabilities in active markets. Level 2 - Observable inputs other than Level 1 that are observable, either directly or indirectly, in the marketplace for identical or similar assets and liabilities. Level 3 - Unobservable inputs that are supported by little or no market data, where values are derived from techniques in which one or more significant inputs are unobservable. Share-Based Compensation Equity-Based Awards The Company applies the fair value method of accounting for share-based compensation, which requires all such compensation to employees, including the grant of employee stock options, to be recognized in the consolidated statements of operations and comprehensive loss based on its fair value at the measurement date (generally the grant date). The expense associated with share-based compensation is recognized over the requisite service period of each award. For awards with only service conditions and graded-vesting features, the Company recognizes compensation cost on a straight-line basis over the requisite service period. For awards with performance conditions, once achievement of the performance condition becomes probable, compensation cost is recognized over the expected period from the date the performance condition becomes probable to the date the performance condition is expected to be achieved. The Company will reassess the probability of vesting at each reporting period for performance awards and adjust compensation cost based on its probability assessment. Share-based awards granted to non-employee directors as compensation for serving on the Company’s board of directors are accounted for in the same manner as employee share-based compensation awards. The fair value of each option grant is estimated using a Black-Scholes option-pricing model on the grant date using expected volatility, risk-free interest rate, expected life of options and fair value per share assumptions. Due to limited historical data, the Company estimates stock price volatility based on the actual volatility of comparable publicly traded companies over the expected life of the option. In evaluating similarity, the Company considered factors such as industry, stage of life cycle, financial leverage, size and risk profile. The Company does not have sufficient stock option exercise history to estimate the expected term of employee stock options and thus continues to calculate expected life based on the mid-point between the vesting date and the contractual term, which is in accordance with the simplified method. The expected term for share-based compensation granted to non-employees is the contractual life. The risk-free rate is based on the U.S. Treasury yield curve during the expected life of the option. The Company estimates forfeitures based on the historical experience of the Company and adjusts the estimated forfeiture rate based upon actual experience. Liability-Based Awards Stock appreciation rights (“SARs”) that include cash settlement features are accounted for as liability-based awards pursuant to ASC 718 Share Based Payments . The fair value of such SARs is estimated using a Black-Scholes option-pricing model on each financial reporting date using expected volatility, risk-free interest rate, expected life and fair value per share assumptions. The fair value of obligations under the Tangible Stockholder Return Plan are estimated using a Monte Carlo simulation approach. The Company’s common stock price is simulated under the Geometric Brownian Motion framework under each simulation path. The other assumptions for the Monte Carlo simulation include the risk-free interest rate, estimated volatility and the expected term. The fair value of each liability award is estimated with a valuation model that uses certain assumptions, such as the award date, expected volatility, risk-free interest rate, expected life of the award and fair value per share assumptions. Due to limited historical data, the Company estimates stock price volatility based on the actual volatility of comparable publicly traded companies over the expected term. In evaluating similarity, the Company considered factors such as industry, stage of life cycle, financial leverage, size and risk profile. The expected term for liability-based awards is the estimated contractual life. The risk-free rate is based on the U.S. Treasury yield curve during the expected life of the award. Income Taxes Deferred tax assets and liabilities are determined based on the temporary differences between the financial statement carrying amounts and the tax bases of assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. In estimating future tax consequences, all expected future events are considered other than enactment of changes in the tax law or rates. The Company did not record a federal or state income tax benefit for the years ended December 31, 2019 and 2018 due to its conclusion that a full valuation allowance is required against the Company’s deferred tax assets. The determination of recording or releasing a tax valuation allowance is made, in part, pursuant to an assessment performed by management regarding the likelihood that the Company will generate future taxable income against which benefits of its deferred tax assets may or may not be realized. This assessment requires management to exercise judgment and make estimates with respect to its ability to generate taxable income in future periods. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The Company’s policy for recording interest and penalties is to record them as a component of general and administrative expenses. As of December 31, 2019 and 2018 , the Company accrued no interest and penalties related to uncertain tax positions. Tax years 2016-2018 remain open to examination by the major taxing jurisdictions to which the Company is subject. Additionally, years prior to 2016 are also open to examination to the extent of loss and credit carryforwards from those years. In accordance with Section 382 of the Internal Revenue Code of 1986, as amended, a change in equity ownership of greater than 50% within a three-year period results in an annual limitation on the Company’s ability to utilize its net operating loss carryforwards created during the tax periods prior to the change in ownership. The Company has not determined whether ownership changes exceeding this threshold, including the Company’s IPO and the January 2018 Offering, have occurred. If a change in equity ownership has occurred which exceeds the Section 382 threshold, a portion of the Company’s net operating loss carryforwards may be limited. Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the years ended December 31, 2019 and 2018 , comprehensive loss was equal to net loss. Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period. Diluted net loss per share is the same as basic net loss per share, since the effects o

KNOW Bio LLC KNOW Bio LLC

KNOW Bio LLC KNOW Bio LLC	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
KNOW Bio LLC	KNOW Bio, LLC On December 30, 2015, the Company completed the distribution of 100% of the outstanding member interests of KNOW Bio, LLC (“KNOW Bio”), a former wholly owned subsidiary of the Company, to Novan’s stockholders (the “Distribution”), pursuant to which KNOW Bio became an independent privately held company. KNOW Bio is an independent, privately held company with a portfolio of operating subsidiaries that are advancing nitric oxide-based therapies using technology that is proprietary and/or in fields where they have exclusive intellectual property rights. The Company does not own any equity interest in KNOW Bio, has no common management or board representation at KNOW Bio, and the contractual arrangements between the two entities do not provide the Company with decision-making authority or power to influence KNOW Bio’s drug and medical device development activities. The Company conducted an initial assessment of KNOW Bio under the variable interest consolidation model pursuant to FASB ASC 810, Consolidation , at the time of the Distribution in 2015 and has monitored KNOW Bio during each subsequent reporting period, including two required ASC 810 reassessments performed during 2017. The Company has consistently determined that KNOW Bio should not be consolidated in its consolidated financial statements. In the fourth quarter of 2018, KNOW Bio and its operating subsidiaries received significant additional equity investments that enable progression of their technology. These events required the Company to conduct another reassessment of variable interest entity characteristics, pursuant to FASB ASC 810-10, Consolidation , in which it determined that KNOW Bio should not be consolidated in its consolidated financial statements. KNOW Bio Technology Agreements In connection with the Distribution, the Company entered into exclusive license agreements and sublicense agreements with KNOW Bio, as described below. The agreements will continue for so long as there is a valid patent claim under the respective agreement, unless earlier terminated, and upon expiration, will continue as perpetual non-exclusive licenses. KNOW Bio has the right to terminate each such agreement, for any reason upon 90 days advance written notice to the Company. License of existing and potential future intellectual property to KNOW Bio. The Company and KNOW Bio entered into an exclusive license agreement dated December 29, 2015 (the “KNOW Bio License Agreement”). Pursuant to the terms of the KNOW Bio License Agreement, the Company granted to KNOW Bio exclusive licenses, with the right to sublicense, under certain U.S. and foreign patents and patent applications that were controlled by the Company as of December 29, 2015 or that became controlled by the Company between that date and December 29, 2018, directed towards nitric-oxide releasing compositions and methods of manufacturing thereof, including methods of manufacturing Nitricil compounds and other nitric oxide-based therapeutics. Sublicense of UNC and other third party intellectual property to KNOW Bio. The Company and KNOW Bio also entered into sublicense agreements dated December 29, 2015 (the “KNOW Bio Sublicense Agreements” and together with the KNOW Bio License Agreement, the “Original KNOW Bio Agreements”). Pursuant to the terms of the KNOW Bio Sublicense Agreements, the Company granted to KNOW Bio exclusive sublicenses, with the ability to further sublicense, under certain of the U.S. and foreign patents and patent applications exclusively licensed to the Company from UNC under the Amended, Restated and Consolidated License Agreement dated June 27, 2012, as amended (the “UNC License Agreement”), and another third party directed towards nitric oxide-releasing compositions, to develop and commercialize products utilizing the licensed technology. Under the exclusive sublicense to the UNC patents and applications (the “UNC Sublicense Agreement”), KNOW Bio is subject to the terms and conditions under the UNC License Agreement, including milestone and diligence payment obligations. However, pursuant to the terms of the UNC License Agreement, the Company is directly obligated to pay UNC any future milestones or royalties, including those resulting from actions conducted by the Company’s sublicensees, including KNOW Bio. Therefore, in the event of KNOW Bio non-performance with respect to its obligations under the UNC Sublicense Agreement, the Company would be obligated to make such payments to UNC. KNOW Bio would then become obligated to repay the Company pursuant to the UNC Sublicense Agreement, otherwise KNOW Bio would be in breach of its agreements with the Company and intellectual property rights would revert back to the Company. There were no milestone or royalty payments required during the years ended December 31, 2019 and 2018 . Amendments to License and Sublicense Agreements with KNOW Bio On October 13, 2017, the Company and KNOW Bio entered into certain amendments to the Original KNOW Bio Agreements (the “KNOW Bio Amendments”). Pursuant to the terms of the KNOW Bio Amendments, the Company re-acquired from KNOW Bio exclusive, worldwide rights under certain U.S. and foreign patents and patent applications controlled by the Company as of December 29, 2015, and that became controlled by the Company between December 29, 2015 and December 29, 2018, directed towards nitric oxide-releasing compositions and methods of manufacturing thereof, including methods of manufacturing Nitricil compounds, and other nitric oxide-based therapeutics, to develop and commercialize products for all diagnostic, therapeutic, prophylactic and palliative uses for any disease, condition or disorder caused by certain oncoviruses (the “Oncovirus Field”). The Company also obtained a three -year exclusive option, subject to payment of separate option exercise fees, to include up to four additional specified oncoviruses in the Oncovirus Field. KNOW Bio also granted to the Company an exclusive license, with the right to sublicense, under any patents and patent applications which became controlled by KNOW Bio during the three -year period between December 29, 2015 and December 29, 2018 and directed towards nitric oxide-releasing compositions and methods of manufacturing thereof, including methods of manufacturing Nitricil compounds, and other nitric oxide-based therapeutics, but not towards medical devices, to develop and commercialize products for use in the Oncovirus Field. Upon execution of the KNOW Bio Amendments, in exchange for the Oncovirus Field rights, the Company paid a non-refundable upfront payment of $250 . Products the Company develops in the Oncovirus Field based on Nitricil will not be subject to any further milestones, royalties or sublicensing payment obligations to KNOW Bio under the KNOW Bio Amendments. However, if the Company develops products in the Oncovirus Field that incorporate a certain nitric oxide-releasing composition specified in the KNOW Bio Amendments and (i) are covered by KNOW Bio patents or (ii) materially use or incorporate know-how of KNOW Bio or the Company related to such composition that was created between December 29, 2015 and December 29, 2018, the Company would be obligated to make the certain contingent milestone and royalty payments to KNOW Bio under the KNOW Bio Amendments. The rights granted to the Company in the Oncovirus Field in the KNOW Bio Amendments continue for so long as there is a valid patent claim under the Original KNOW Bio Agreements, and upon expiration continue on a perpetual non-exclusive basis, and are subject to the termination rights of KNOW Bio and the Company that are set forth in the Original KNOW Bio Agreements. In addition, under the KNOW Bio Amendments, KNOW Bio may terminate the rights granted to the Company in the Oncovirus Field if: (i) the Company does not file a first investigational new drug (“IND”) application with the FDA for a product in the Oncovirus Field by October 2020; or (ii) the Company does not file a first new drug application (“NDA”) with the FDA by October 2025 for a product in the Oncovirus Field and does not otherwise have any active clinical programs related to the Oncovirus Field at such time. The KNOW Bio Amendments also provide a mechanism whereby either party can cause a new chemical entity (“NCE”) covered by the Original KNOW Bio Agreements to become exclusive to such party by filing an IND on the NCE. An NCE that becomes exclusive to a party under this provision may not be commercialized by the other party until the later of expiration of patents covering the NCE or regulatory exclusivity covering the NCE. A party who obtains exclusivity for an NCE must advance development of the NCE pursuant to terms of the KNOW Bio Amendments in order to maintain such exclusivity; otherwise, such exclusivity will expire. The terms of the KNOW Bio Amendments were negotiated at arms-length and do not provide the Company with an ability to significantly influence KNOW Bio or its operations.

Research and Development Licens

Research and Development Licenses	12 Months Ended
	Dec. 31, 2019
Research and Development [Abstract]
Research And Development Licenses	Research and Development Licenses The Company has entered into various licensing agreements with universities and other research institutions under which the Company receives the rights, and in some cases substantially all of the rights, of the inventors, assignees or co-assignees to produce and market technology protected by certain patents and patent applications. The Company’s primary license agreement is with UNC and has been described in further detail within the subsection below. The counterparties to the Company’s various other licensing agreements are the University of Akron Research Foundation, Hospital for Special Surgery, Strakan International S.a.r.l., which is a licensee of the University of Aberdeen, KIPAX AB and KNOW Bio. The Company is generally required to make milestone payments based on development milestones and will be required to make royalty payments based on a percentage of future sales of covered products or a percentage of sublicensing revenue. Costs to acquire rights under license agreements and pre-commercialization milestone payments are classified as research and development expenses in the consolidated statements of operations. Research and development expense recognized in connection with the incurrence of such costs totaled zero and $20 during the years ended December 31, 2019 and 2018 , respectively. The Company is generally required by the various licensing agreements to reimburse the licensor for certain legal and other patent related costs. These costs are expensed as incurred and are classified as general and administrative expenses in the consolidated statements of operations. General and administrative expense recognized in connection with the incurrence of such costs totaled $93 and $74 during the years ended December 31, 2019 and 2018 , respectively. These license arrangements could require the Company to make payments upon achievement of certain milestones by the Company. As future royalty payments are directly related to future revenues (either sales or sublicensing), future commitments cannot be determined. No accrual for future payments under these agreements has been recorded, as the Company cannot estimate if, when or in what amount payments may become due. UNC License Agreement The UNC License Agreement provides the Company with an exclusive license to issued patents and pending applications directed to the Company’s library of Nitricil compounds, including patents issued in the U.S., Japan and Australia, with claims intended to cover NVN1000, the NCE for the Company’s current product candidates. The UNC License Agreement requires the Company to pay UNC up to $425 in regulatory and commercial milestones on a licensed product by licensed product basis and a running royalty percentage in the low single digits on net sales of licensed products. Licensed products include any products being developed by the Company or by its sublicensees. Unless earlier terminated by the Company at its election, or if the Company materially breaches the agreement or becomes bankrupt, the UNC License Agreement remains in effect on a country by country and licensed product by licensed product basis until the expiration of the last to expire issued patent covering such licensed product in the applicable country. The projected date of expiration of the last to expire of the patents issued under the UNC Agreement is 2033 .

Licensing Arrangements

Licensing Arrangements	12 Months Ended
	Dec. 31, 2019
Collaboration Arrangements [Abstract]
Licensing Arrangements	Licensing Arrangements Sato License Agreement Significant Terms On January 12, 2017, the Company entered into a license agreement, and related first amendment, with Sato Pharmaceutical Co., Ltd. (“Sato”), relating to SB204, its drug candidate for the treatment of acne vulgaris in Japan (the “Sato Agreement”). Pursuant to the Sato Agreement, the Company granted to Sato an exclusive, royalty-bearing, non-transferable right and license under certain of the Company’s intellectual property rights, with the right to sublicense with the Company’s prior written consent, to develop, use and sell products in Japan that incorporate SB204 in certain topical dosage forms for the treatment of acne vulgaris, and to make the finished form of such products. On October 5, 2018, the Company and Sato entered into the second amendment (the “Sato Amendment”) to the Sato Agreement (collectively, the “Amended Sato Agreement”). The Sato Amendment expanded the Sato Agreement to include SB206, the Company’s drug candidate for the treatment of viral skin infections. Pursuant to the Amended Sato Agreement, the Company granted to Sato an exclusive, royalty-bearing, non-transferable license under certain of its intellectual property rights, with the right to sublicense with the Company’s prior written consent, to develop, use and sell products in Japan that incorporate SB204 or SB206 in certain topical dosage forms for the treatment of acne vulgaris or viral skin infections, respectively, and to make the finished form of such products. The Company or its designated contract manufacturer will supply finished product to Sato for use in the development of SB204 and SB206 in the licensed territory. The rights granted to Sato do not include the right to manufacture the active pharmaceutical ingredient (“API”) of SB204 or SB206; rather, the parties agreed to negotiate a commercial supply agreement pursuant to which the Company or its designated contract manufacturer would be the exclusive supplier to Sato of the API for the commercial manufacture of licensed products in the licensed territory. Under the terms of the Amended Sato Agreement, the Company also has exclusive rights to certain intellectual property that may be developed by Sato in the future, which the Company could choose to use for its own development and commercialization of SB204 or SB206 outside of Japan. Under the Amended Sato Agreement, in exchange for the SB204 and SB206 license rights granted to Sato, Sato agreed to pay the Company the following: • An upfront payment of 1.25 billion Japanese Yen, or “JPY”, payable in installments of 0.25 billion JPY, 0.5 billion JPY and 0.5 billion JPY on October 5, 2018, February 14, 2019 and September 13, 2019, respectively. This is in addition to the 1.25 billion JPY (approximately $10,813 USD) paid on January 19, 2017 following the execution of the Sato Agreement on January 12, 2017. On October 23, 2018, the Company received the first installment from the Amended Sato Agreement of 0.25 billion JPY (approximately $2,224 USD). On March 14, 2019, the Company received the second installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,460 USD). On November 7, 2019, the Company received the third installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,554 USD). • Up to an aggregate of 1.75 billion JPY (adjusted from 2.75 billion JPY in the Sato Agreement) upon the achievement of various development and regulatory milestones, including (i) a 0.25 billion JPY (approximately $2,162 USD) milestone payment received during the fourth quarter of 2018 following Sato’s initiation of a Phase 1 trial in Japan and (ii) an aggregate of 1.0 billion JPY that becomes payable upon the earlier occurrence of specified fixed future dates or the achievement of milestone events. • Up to an aggregate of 3.9 billion JPY (adjusted from 0.9 billion JPY in the Sato Agreement) upon the achievement of various commercial milestones. • A tiered royalty ranging from a mid-single digit to a low-double digit percentage (adjusted from a mid-single digit percentage in the Sato Agreement) of net sales of licensed products in the licensed territory, subject to a reduction in the royalty payments in certain circumstances. The term of the Amended Sato Agreement (and the period during which Sato must pay royalties under the amended license agreement) expires on the twentieth anniversary of the first commercial sale of a licensed product in the licensed field in the licensed territory (adjusted from the tenth anniversary of the first commercial sale in the license agreement). The term of the Amended Sato Agreement may be renewed with respect to a licensed product by mutual written agreement of the parties for additional two -year periods following expiration of the initial term. All other material terms of the license agreement remain unchanged by the Sato Amendment. Sato is responsible for funding the development and commercial costs for the program that are specific to Japan. The Company is obligated to perform certain oversight, review and supporting activities for Sato, including: (i) using commercially reasonable efforts to obtain marketing approval of SB204 and SB206 in the U.S; (ii) sharing all future scientific information the Company may obtain during the term of the Amended Sato Agreement pertaining to SB204 and SB206; (iii) performing certain additional preclinical studies if such studies are deemed necessary by the Japanese regulatory authority, up to and not to exceed a total cost of $1,000 ; and (iv) participating in a joint committee that oversees, reviews and approves Sato’s development and commercialization activities under the Amended Sato Agreement. Additionally, the Company has granted Sato the option to use the Company’s trademarks in connection with the commercialization of licensed products in the licensed territory for no additional consideration, subject to the Company’s approval of such use. The Amended Sato Agreement may be terminated by (i) Sato without cause upon 120 days’ advance written notice to the Company; (ii) either party in the event of the other party’s uncured material breach upon 60 days’ advance written notice; (iii) force majeure; (iv) either party in the event of the other party’s dissolution, liquidation, bankruptcy or insolvency; and (v) the Company immediately upon written notice if Sato challenges the validity, patentability, or enforceability of any of the Company’s patents or patent applications licensed to Sato under the Amended Sato Agreement. In the event of a termination, no portion of the upfront fees received from Sato are refundable. Research and Development Arrangements Royalty and Milestone Payments Purchase Agreement with Reedy Creek Investments LLC On April 29, 2019, the Company entered into a royalty and milestone payments purchase agreement (the “Purchase Agreement”) with Reedy Creek Investments LLC (“Reedy Creek”), pursuant to which Reedy Creek provided funding to the Company in an initial amount of $25,000 , which the Company will use primarily to pursue the development, regulatory approval and commercialization (including through out-license agreements and other third party arrangements) activities for SB206, a topical anti-viral gel being developed for the treatment of molluscum contagiosum, and advancing programmatically such activities with respect to SB204, a once-daily, topical monotherapy being developed for the treatment of acne vulgaris, and SB414, a topical cream-based product candidate being developed for the treatment of atopic dermatitis. Reedy Creek was to provide additional funding to the Company of $10,000 contingent upon the achievement by the Company of SB206 clinical trial success, defined as (i) the achievement, no later than March 31, 2020, of statistically significant rates of complete clearance of lesions for molluscum contagiosum in humans at week 12 in each of the two Phase 3 clinical trials or any other primary endpoint required or accepted by the FDA for the SB206 product; or (ii) equivalent achievement (as agreed upon by the parties). See Note 16—Subsequent Events regarding the January 2020 announcement of top-line results from two pivotal Phase 3 clinical trials of SB206 for the treatment of molluscum contagiosum. SB206 did not achieve statistically significant results in the primary endpoint in both trials, which was the complete clearance of all molluscum lesions at Week 12. Based on the top line efficacy results from the Phase 3 SB206 program released in January 2020, the Company understands that Reedy Creek will not be paying the Company the contingent $10,000 of additional funding. Pursuant to the Purchase Agreement, the Company will pay Reedy Creek ongoing quarterly payments, calculated based on an applicable percentage per product of any upfront fees, milestone payments, royalty payments or equivalent payments received by the Company pursuant to any out-license agreement for SB204, SB206 or SB414 in the United States, Mexico or Canada, net of any upfront fees, milestone payments, royalty payments or equivalent payments paid by the Company to third parties pursuant to any agreements under which the Company has in-licensed intellectual property with respect to such products in the United States, Mexico or Canada. The applicable percentage used for determining the ongoing quarterly payments, applied to amounts received directly by the Company pursuant to any out-license agreement for each product, ranges from 10% for SB206 to 20% for SB204 and SB414. However, the agreement provides that the applicable percentage for each product will be 25% for fees or milestone payments received by the Company (but not royalty payments received by the Company) until Reedy Creek has received payments under the Purchase Agreement equal to the total funding amount provided by Reedy Creek under the Purchase Agreement. If the Company decides to commercialize any product on its own following regulatory approval, as opposed to commercializing through an out-license agreement or other third-party arrangement, the Company will be obligated to pay Reedy Creek a low single digits royalty on net sales of such products. The Company has determined that the Reedy Creek Purchase Agreement is within the scope of ASC 730-20, Research and Development Arrangements . The Company concluded that there has not been a substantive and genuine transfer of risk related to the Purchase Agreement as (i) Reedy Creek has the opportunity to recover its investment regardless of the outcome of the research and development programs within the scope of the agreement (prior to commercialization of any in scope assets through potential out-licensing agreements and related potential future milestone payments); and (ii) there is a presumption that the Company is obligated to pay Reedy Creek amounts equal to its investment based on the related party relationship at the time the parties entered into the Purchase Agreement. The Purchase Agreement is a broad funding arrangement, due to (i) the multi-asset, or portfolio approach including three developmental assets that are within the scope of the arrangement; and (ii) Reedy Creek’s approximate 15% ownership of the outstanding shares of common stock of the Company. As such, the Company has determined that the appropriate accounting treatment under ASC 730-20 is to record the initial proceeds of $25,000 as cash and cash equivalents, as the Company has the ability to direct the usage of funds, and a long-term liability within its classified balance sheet. The long-term liability will remain until the Company receives future milestones from other potential third parties, as defined within the Purchase Agreement, of which 25% will be contractually owed to Reedy Creek. If potential future milestones are received by the Company, and become partly due to Reedy Creek, the corresponding partial repayment to Reedy Creek will result in a ratable reduction of the total long-term obligation to repay the initial purchase price. Development Funding and Royalties Agreement with Ligand Pharmaceuticals Incorporated On May 4, 2019, the Company entered into a development funding and royalties agreement (the “Funding Agreement”) with Ligand, pursuant to which Ligand provided funding to the Company of $12,000 , which the Company will use to pursue the development and regulatory approval of SB206, a topical anti-viral gel being developed for the treatment of molluscum contagiosum. Pursuant to the Funding Agreement, the Company will pay Ligand up to $20,000 in milestone payments upon the achievement by the Company of certain regulatory and commercial milestones associated with SB206 or any product that incorporates or uses NVN1000, the active pharmaceutical ingredient for the Company’s clinical stage product candidates, for the treatment of molluscum contagiosum. In addition to the milestone payments, the Company will pay Ligand tiered royalties ranging from 7% to 10% based on annual aggregate net sales of such products in the United States, Mexico or Canada. The Company has determined that the Ligand transaction is within the scope of ASC 730-20 as it represents an obligation to perform contractual services for the development of SB206 using commercially reasonable efforts. In addition, the Funding Agreement also states that if all development of SB206 is ceased prior to the first regulatory approval, the Company must pay to Ligand an amount equal to the purchase price less the amount spent in accordance with the development budget on development activities conducted prior to such cessation. As such, the Company has concluded that the appropriate accounting treatment under ASC 730-20 is to record the initial proceeds of $12,000 , as a liability and as restricted cash on its consolidated balance sheet, as the funds can only be used for the progression of SB206. The Company amortizes the liability ratably during each reporting period, based on the Ligand funding as a percentage of the total direct costs incurred by the Company during the reporting period related to the estimated total cost to progress the SB206 program to a regulatory approval in the U.S. The ratable Ligand funding is presented within the consolidated statement of operations as an offset to research and development expenses associated with the SB206 program. During the first quarter of 2020, the Company expects to reassess the estimated total cost to progress the SB206 program to a U.S. regulatory approval, as the Company considers how such estimated costs may potentially be affected by various factors, including (i) the recent results from the Company’s SB206 Phase 3 trials in the U.S., including but not limited to top-line efficacy results announced in January 2020, (ii) the Company’s plans and timelines for potential further clinical development of SB206 in the U.S., which is subject to additional funding and feedback from a Type C meeting with the FDA scheduled for April 1, 2020, and (iii) the Company’s in-house drug manufacturing capabilities and the progression of the Company’s manufacturing technology transfer projects with third-party contract manufacturing organizations. The initial restricted cash balance was also reduced ratably during interim reporting periods in 2019 in a manner consistent with the amortization method for the Ligand funding liability balance. As of December 31, 2019, the aggregate amount spent in accordance with the SB206 development budget on SB206 development activities had exceeded the $12,000 purchase price, causing the aforementioned repayment provision provided for in the Funding Agreement to no longer be enforceable. Therefore, the Company reported no restricted cash balance related to the Funding Agreement, as of December 31, 2019 in its consolidated balance sheet. For the year ended December 31, 2019 , the Company recorded $8,185 as contra-research and development expense related to the SB206 developmental program, funded by Ligand.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Sato Agreement The Company assessed the Sato Agreement in accordance with Topic 606 and concluded that the contract counterparty, Sato, is a customer within the scope of Topic 606. The Company identified the following promises under the Sato Agreement: (i) the grant of the intellectual property license to Sato; (ii) the obligation to participate in a joint committee that oversees, reviews, and approves Sato’s research and development activities and provides advisory support during Sato’s development process; (iii) the obligation to manufacture and supply Sato with all quantities of licensed product required for development activities in Japan; and (iv) the stand-ready obligation to perform any necessary repeat preclinical studies, up to $1,000 in cost. The Company determined that these promises were not individually distinct because Sato can only benefit from these licensed intellectual property rights and services when bundled together; they do not have individual benefit or utility to Sato. As a result, all promises have been combined into a single performance obligation. The Sato Agreement also provides that the two parties agree to negotiate in good faith the terms of a commercial supply agreement pursuant to which the Company or a third party manufacturer would be the exclusive supplier to Sato of the API for the commercial manufacture of licensed products in the licensed territory. The Company concluded this obligation to negotiate the terms of a commercial supply agreement does not create (i) a legally enforceable obligation under which the Company may have to perform and supply Sato with API for commercial manufacturing; or (ii) a material right because the incremental commercial supply fee consideration agreed upon between the parties in the Sato Agreement is representative of a stand-alone selling price for the supply of API and does not represent a discount. Therefore, this contract provision is not considered to be a promise to deliver goods or services and is not a performance obligation or part of the combined single performance obligation described above. Amended Sato Agreement On October 5, 2018, the Company and Sato entered into the Amended Sato Agreement. The Sato Amendment expanded the Sato Agreement to include SB206, the Company’s drug candidate for the treatment of viral skin infections. The Company assessed the Amended Sato Agreement in accordance with Topic 606 and concluded the contract modification should incorporate the additional goods and services provided for in the Amendment into the existing, partially satisfied single bundled performance obligation that will continue to be delivered to Sato over the remaining development period. This contract modification accounting is concluded to be appropriate as the additional goods and services conveyed under the Sato Amendment were determined to not be distinct from the single performance obligation, and the additional consideration provided did not reflect the standalone selling price of those additional goods and services. As such, the Company recorded a cumulative adjustment as of the amendment execution date to reflect revenue that would have been recognized cumulatively for the partially completed bundled performance obligation. The Company concluded that the following consideration would be included in the transaction price as they were (i) received prior to December 31, 2019, or (ii) payable upon specified fixed dates in the future and are not contingent upon clinical or regulatory success in Japan: • The 1.25 billion JPY (approximately $10,813 USD) original upfront payment received on January 19, 2017 following the execution of the Sato Agreement on January 12, 2017. • A milestone payment of 0.25 billion JPY (approximately $2,162 USD) received during the fourth quarter of 2018 following Sato’s initiation of a Phase 1 trial in Japan. • The Sato Amendment upfront payment of 1.25 billion JPY, payable in installments of 0.25 billion JPY, 0.5 billion JPY and 0.5 billion JPY on October 5, 2018, February 14, 2019 and September 13, 2019, respectively. On October 23, 2018, the Company received the first installment from the Amended Sato Agreement of 0.25 billion JPY (approximately $2,224 USD). On March 14, 2019, the Company received the second installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,460 USD). On November 7, 2019, the Company received the third installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,554 USD). • An aggregate of 1.0 billion JPY in non-contingent milestone payments that become payable upon the earlier occurrence of specified fixed dates in the future or the achievement of specified milestone events. The following table presents the Company’s contract assets and contract liabilities balances for the periods indicated. Contract Asset Contract Liability Net Deferred Revenue December 31, 2018 $ 17,790 $ 24,757 $ 6,967 December 31, 2019 $ 8,974 $ 20,478 $ 11,504 Short-term Deferred Revenue Long-term Deferred Revenue Net Deferred Revenue December 31, 2018 $ 4,401 $ 2,566 $ 6,967 December 31, 2019 $ 4,428 $ 7,076 $ 11,504 The Company has recorded the Sato Agreement and Amended Sato Agreement transaction price, including the upfront payments received and the unconstrained variable consideration, as deferred revenue (comprised of (i) a contract liability; net of (ii) a contract asset). The change in the net deferred revenue balances during the year ended December 31, 2019 was associated with the receipts of the second and third installment payments of 0.5 billion JPY (approximately $4,460 USD), and 0.5 billion JPY (approximately $4,554 USD), respectively, and recognition of license and collaboration revenue associated with the Company’s performance during the period (continued amortization of deferred revenue). During the years ended December 31, 2019 and 2018 , the Company recognized $4,477 and $5,982 , respectively, in license and collaboration revenue under this agreement. The Company has concluded that the above consideration is probable of not resulting in a significant revenue reversal and therefore included in the transaction price and is allocated to the single performance obligation. No other variable consideration under the Amended Sato Agreement is probable of not resulting in a significant revenue reversal as of December 31, 2019 and therefore, is currently fully constrained and excluded from the transaction price. The Company evaluated the timing of delivery for each of the obligations and concluded that a time-based input method is most appropriate because Sato is accessing and benefiting from the intellectual property and technology (the predominant items of the combined performance obligation) ratably over the duration of Sato’s estimated development period in Japan. Although the Company concluded that the intellectual property is functional rather than symbolic, the services provided under the performance obligation are provided over time. Therefore, the allocated transaction price will be recognized using a time-based input method that results in straight-line recognition over the Company’s performance period. Prior to the Sato Amendment, the Company estimated the Sato Agreement development timeline for the SB204 product candidate to be approximately 5 years , starting in February 2017 and completing in the first quarter of 2022. With the Amended Sato Agreement, the Company and Sato are now developing both the SB204 and SB206 product candidates for the Japan territory. The parties continue to work collaboratively to reach agreement, but have not yet reached agreement, with respect to the combined SB204 and SB206 development plan for the Japan territory, including a corresponding timeline and estimated duration for the combined development program. The Company’s current estimated timeline is 7.5 years , starting in February 2017 and completing in the third quarter of 2024. The Company monitors and reassesses the estimated performance period for purposes of revenue recognition during each reporting period. The Company expects to reassess the estimated performance period during the first quarter of 2020, as the Company considers how the combined SB204 and SB206 development program timeline in Japan may potentially be affected by various factors, including (i) the recent results from the Company’s SB206 Phase 3 trials in the U.S., including but not limited to top-line efficacy results announced in January 2020, (ii) the Company’s plans and timelines for potential further clinical development of SB206 in the U.S., which is subject to additional funding and feedback from a Type C meeting with the FDA scheduled for April 1, 2020, and (iii) the Company’s in-house drug manufacturing capabilities and the progression of the Company’s manufacturing technology transfer projects with third-party contract manufacturing organizations. Therefore, if the duration of the combined SB204 and SB206 development program timeline is affected by the establishment or subsequent adjustments to a mutually agreed upon SB204 and SB206 development plan in the Japan territory, the Company will adjust its estimated performance period for revenue recognition purposes accordingly, as needed. In future periods, the Company will lift the variable consideration constraint from each contingent payment when there is no longer a probable likelihood of significant revenue reversal. When the constraint is lifted from a milestone payment, the Company will recognize the incremental transaction price using the same time-based input method that is being used to recognize the revenue, which results in straight-line recognition over the performance period. If the Company’s performance is not yet completed at the time that the constraint is lifted, a cumulative catch-up adjustment will be recognized in the period. If no other performance is required by the Company at the time the constraint is lifted, the Company expects to recognize all revenue associated with such milestone payments at the time that the constraint is lifted. Contract costs—Sato Agreement The Company has incurred certain fees and costs in the process of obtaining the Amended Sato Agreement that were payable upon contract execution and, therefore, have been recognized as other assets and amortized as general and administrative expense on a straight-line basis over the same estimated performance period being used to recognize the associated revenue. These fees are associated with the following two arrangements and are described as follows: • The Company entered into an agreement with a third party to assist the Company in exploring the licensing opportunity which led to the execution of the Sato Agreement. The Company is obligated to pay the third party a low-single-digit percentage of all upfront and milestone payments the Company receives from Sato under the Amended Sato Agreement. • The intellectual property rights granted to Sato under the Sato Agreement include certain intellectual property rights which the Company has licensed from UNC. Under the UNC License Agreement described in Note 3—Research and Development Licenses, the Company is obligated to pay UNC a running royalty percentage in the low single digits on net sales of licensed products, including net sales that may be generated by Sato. Additionally, the Company is obligated to make payments to UNC that represent the portion of the Sato upfront and milestone payments that were estimated to be directly attributable to the UNC intellectual property rights included in the license to Sato. The Company has also accrued certain fees that it will pay to the third party and to UNC in the future upon receipt of non-contingent installment and milestone payments from Sato. As of December 31, 2019 , the Company had recorded capitalized contract acquisition costs of $533 in other assets and had accrued $230 in the accompanying balance sheet. For the years ended December 31, 2019 and 2018 the Company paid fees totaling $228 and $111 , respectively. Performance Obligations under the Sato Agreement The net amount of existing performance obligations under long-term contracts unsatisfied as of December 31, 2019 was $11,504 . The Company expects to recognize approximately 22% of the remaining performance obligations as revenue over the next 12 months , and the balance thereafter. The Company applied the practical expedient and does not disclose information about variable consideration related to sales-based or usage-based royalties promised in exchange for a license of intellectual property. This expedient specifically applied to the sales-based milestone payments that are present in the Amended Sato Agreement ( 3.9 billion JPY), as well as percentage-based royalty payments in the Sato Agreement that are contingent upon future sales. Government Contracts and Grant Revenue The Company assessed the following Federal grants in accordance with Topic 958 and concluded that both represent conditional non-exchange transactions. In August 2019, the Company received a Phase 1 Federal grant of approximately $223 from the National Institutes of Health. The funds are to be used to advance formulation development of a nitric oxide-containing intravaginal gel (WH602) designed to treat high-risk human papilloma virus (“HPV”) infections that can lead to cervical intraepithelial neoplasia (“CIN”). The specific focus is to ensure the nitric oxide delivery from the gel replicates doses of nitric oxide previously demonstrated to be effective against HPV in the Company’s clinical and in vitro studies. Upon completion of grant Phase 1 preclinical work, the Company may be eligible to receive further awards for Phase 2 and 3 extensions under this grant. Revenue recognized under this grant was $83 during the year ended December 31, 2019 . In September 2019, the Company received a grant from the U.S. Department of Defense’s Congressionally Directed Medical Research Programs of approximately $1,113 as part of its Peer Reviewed Cancer Research Program. The grant will support the development of a non-gel formulation product candidate (WH504) designed to treat high-risk HPV infections that can lead to CIN, with well-characterized physical chemical properties suitable for intravaginal administration. In addition, the grant will support the evaluation of the effect of varying concentrations and treatment durations of berdazimer sodium (NVN1000) against HPV-18 in human raft cell culture in vitro studies. Revenue recognized under this grant was $336 during the year ended December 31, 2019 . Research and Development Services to KNOW Bio The Company entered into a services agreement with KNOW Bio (the “KNOW Bio Services Agreement”) during 2017 and provided research and development services on a fee-for-service basis. After assessing revenue according to the five-step model of ASC 606, the Company determined that contract research and development services revenue should be recognized in the period in which the services are performed. During the year ended December 31, 2018, the Company recognized $9 in research and development services revenue for services performed under the KNOW Bio Services Agreement. There was no research and development services revenue recognized during the year ended December 31, 2019.

Research and Development Arrang

Research and Development Arrangements	12 Months Ended
	Dec. 31, 2019
Collaboration Arrangements [Abstract]
Research and Development Arrangements	Licensing Arrangements Sato License Agreement Significant Terms On January 12, 2017, the Company entered into a license agreement, and related first amendment, with Sato Pharmaceutical Co., Ltd. (“Sato”), relating to SB204, its drug candidate for the treatment of acne vulgaris in Japan (the “Sato Agreement”). Pursuant to the Sato Agreement, the Company granted to Sato an exclusive, royalty-bearing, non-transferable right and license under certain of the Company’s intellectual property rights, with the right to sublicense with the Company’s prior written consent, to develop, use and sell products in Japan that incorporate SB204 in certain topical dosage forms for the treatment of acne vulgaris, and to make the finished form of such products. On October 5, 2018, the Company and Sato entered into the second amendment (the “Sato Amendment”) to the Sato Agreement (collectively, the “Amended Sato Agreement”). The Sato Amendment expanded the Sato Agreement to include SB206, the Company’s drug candidate for the treatment of viral skin infections. Pursuant to the Amended Sato Agreement, the Company granted to Sato an exclusive, royalty-bearing, non-transferable license under certain of its intellectual property rights, with the right to sublicense with the Company’s prior written consent, to develop, use and sell products in Japan that incorporate SB204 or SB206 in certain topical dosage forms for the treatment of acne vulgaris or viral skin infections, respectively, and to make the finished form of such products. The Company or its designated contract manufacturer will supply finished product to Sato for use in the development of SB204 and SB206 in the licensed territory. The rights granted to Sato do not include the right to manufacture the active pharmaceutical ingredient (“API”) of SB204 or SB206; rather, the parties agreed to negotiate a commercial supply agreement pursuant to which the Company or its designated contract manufacturer would be the exclusive supplier to Sato of the API for the commercial manufacture of licensed products in the licensed territory. Under the terms of the Amended Sato Agreement, the Company also has exclusive rights to certain intellectual property that may be developed by Sato in the future, which the Company could choose to use for its own development and commercialization of SB204 or SB206 outside of Japan. Under the Amended Sato Agreement, in exchange for the SB204 and SB206 license rights granted to Sato, Sato agreed to pay the Company the following: • An upfront payment of 1.25 billion Japanese Yen, or “JPY”, payable in installments of 0.25 billion JPY, 0.5 billion JPY and 0.5 billion JPY on October 5, 2018, February 14, 2019 and September 13, 2019, respectively. This is in addition to the 1.25 billion JPY (approximately $10,813 USD) paid on January 19, 2017 following the execution of the Sato Agreement on January 12, 2017. On October 23, 2018, the Company received the first installment from the Amended Sato Agreement of 0.25 billion JPY (approximately $2,224 USD). On March 14, 2019, the Company received the second installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,460 USD). On November 7, 2019, the Company received the third installment payment related to the Amended Sato Agreement of 0.5 billion JPY (approximately $4,554 USD). • Up to an aggregate of 1.75 billion JPY (adjusted from 2.75 billion JPY in the Sato Agreement) upon the achievement of various development and regulatory milestones, including (i) a 0.25 billion JPY (approximately $2,162 USD) milestone payment received during the fourth quarter of 2018 following Sato’s initiation of a Phase 1 trial in Japan and (ii) an aggregate of 1.0 billion JPY that becomes payable upon the earlier occurrence of specified fixed future dates or the achievement of milestone events. • Up to an aggregate of 3.9 billion JPY (adjusted from 0.9 billion JPY in the Sato Agreement) upon the achievement of various commercial milestones. • A tiered royalty ranging from a mid-single digit to a low-double digit percentage (adjusted from a mid-single digit percentage in the Sato Agreement) of net sales of licensed products in the licensed territory, subject to a reduction in the royalty payments in certain circumstances. The term of the Amended Sato Agreement (and the period during which Sato must pay royalties under the amended license agreement) expires on the twentieth anniversary of the first commercial sale of a licensed product in the licensed field in the licensed territory (adjusted from the tenth anniversary of the first commercial sale in the license agreement). The term of the Amended Sato Agreement may be renewed with respect to a licensed product by mutual written agreement of the parties for additional two -year periods following expiration of the initial term. All other material terms of the license agreement remain unchanged by the Sato Amendment. Sato is responsible for funding the development and commercial costs for the program that are specific to Japan. The Company is obligated to perform certain oversight, review and supporting activities for Sato, including: (i) using commercially reasonable efforts to obtain marketing approval of SB204 and SB206 in the U.S; (ii) sharing all future scientific information the Company may obtain during the term of the Amended Sato Agreement pertaining to SB204 and SB206; (iii) performing certain additional preclinical studies if such studies are deemed necessary by the Japanese regulatory authority, up to and not to exceed a total cost of $1,000 ; and (iv) participating in a joint committee that oversees, reviews and approves Sato’s development and commercialization activities under the Amended Sato Agreement. Additionally, the Company has granted Sato the option to use the Company’s trademarks in connection with the commercialization of licensed products in the licensed territory for no additional consideration, subject to the Company’s approval of such use. The Amended Sato Agreement may be terminated by (i) Sato without cause upon 120 days’ advance written notice to the Company; (ii) either party in the event of the other party’s uncured material breach upon 60 days’ advance written notice; (iii) force majeure; (iv) either party in the event of the other party’s dissolution, liquidation, bankruptcy or insolvency; and (v) the Company immediately upon written notice if Sato challenges the validity, patentability, or enforceability of any of the Company’s patents or patent applications licensed to Sato under the Amended Sato Agreement. In the event of a termination, no portion of the upfront fees received from Sato are refundable. Research and Development Arrangements Royalty and Milestone Payments Purchase Agreement with Reedy Creek Investments LLC On April 29, 2019, the Company entered into a royalty and milestone payments purchase agreement (the “Purchase Agreement”) with Reedy Creek Investments LLC (“Reedy Creek”), pursuant to which Reedy Creek provided funding to the Company in an initial amount of $25,000 , which the Company will use primarily to pursue the development, regulatory approval and commercialization (including through out-license agreements and other third party arrangements) activities for SB206, a topical anti-viral gel being developed for the treatment of molluscum contagiosum, and advancing programmatically such activities with respect to SB204, a once-daily, topical monotherapy being developed for the treatment of acne vulgaris, and SB414, a topical cream-based product candidate being developed for the treatment of atopic dermatitis. Reedy Creek was to provide additional funding to the Company of $10,000 contingent upon the achievement by the Company of SB206 clinical trial success, defined as (i) the achievement, no later than March 31, 2020, of statistically significant rates of complete clearance of lesions for molluscum contagiosum in humans at week 12 in each of the two Phase 3 clinical trials or any other primary endpoint required or accepted by the FDA for the SB206 product; or (ii) equivalent achievement (as agreed upon by the parties). See Note 16—Subsequent Events regarding the January 2020 announcement of top-line results from two pivotal Phase 3 clinical trials of SB206 for the treatment of molluscum contagiosum. SB206 did not achieve statistically significant results in the primary endpoint in both trials, which was the complete clearance of all molluscum lesions at Week 12. Based on the top line efficacy results from the Phase 3 SB206 program released in January 2020, the Company understands that Reedy Creek will not be paying the Company the contingent $10,000 of additional funding. Pursuant to the Purchase Agreement, the Company will pay Reedy Creek ongoing quarterly payments, calculated based on an applicable percentage per product of any upfront fees, milestone payments, royalty payments or equivalent payments received by the Company pursuant to any out-license agreement for SB204, SB206 or SB414 in the United States, Mexico or Canada, net of any upfront fees, milestone payments, royalty payments or equivalent payments paid by the Company to third parties pursuant to any agreements under which the Company has in-licensed intellectual property with respect to such products in the United States, Mexico or Canada. The applicable percentage used for determining the ongoing quarterly payments, applied to amounts received directly by the Company pursuant to any out-license agreement for each product, ranges from 10% for SB206 to 20% for SB204 and SB414. However, the agreement provides that the applicable percentage for each product will be 25% for fees or milestone payments received by the Company (but not royalty payments received by the Company) until Reedy Creek has received payments under the Purchase Agreement equal to the total funding amount provided by Reedy Creek under the Purchase Agreement. If the Company decides to commercialize any product on its own following regulatory approval, as opposed to commercializing through an out-license agreement or other third-party arrangement, the Company will be obligated to pay Reedy Creek a low single digits royalty on net sales of such products. The Company has determined that the Reedy Creek Purchase Agreement is within the scope of ASC 730-20, Research and Development Arrangements . The Company concluded that there has not been a substantive and genuine transfer of risk related to the Purchase Agreement as (i) Reedy Creek has the opportunity to recover its investment regardless of the outcome of the research and development programs within the scope of the agreement (prior to commercialization of any in scope assets through potential out-licensing agreements and related potential future milestone payments); and (ii) there is a presumption that the Company is obligated to pay Reedy Creek amounts equal to its investment based on the related party relationship at the time the parties entered into the Purchase Agreement. The Purchase Agreement is a broad funding arrangement, due to (i) the multi-asset, or portfolio approach including three developmental assets that are within the scope of the arrangement; and (ii) Reedy Creek’s approximate 15% ownership of the outstanding shares of common stock of the Company. As such, the Company has determined that the appropriate accounting treatment under ASC 730-20 is to record the initial proceeds of $25,000 as cash and cash equivalents, as the Company has the ability to direct the usage of funds, and a long-term liability within its classified balance sheet. The long-term liability will remain until the Company receives future milestones from other potential third parties, as defined within the Purchase Agreement, of which 25% will be contractually owed to Reedy Creek. If potential future milestones are received by the Company, and become partly due to Reedy Creek, the corresponding partial repayment to Reedy Creek will result in a ratable reduction of the total long-term obligation to repay the initial purchase price. Development Funding and Royalties Agreement with Ligand Pharmaceuticals Incorporated On May 4, 2019, the Company entered into a development funding and royalties agreement (the “Funding Agreement”) with Ligand, pursuant to which Ligand provided funding to the Company of $12,000 , which the Company will use to pursue the development and regulatory approval of SB206, a topical anti-viral gel being developed for the treatment of molluscum contagiosum. Pursuant to the Funding Agreement, the Company will pay Ligand up to $20,000 in milestone payments upon the achievement by the Company of certain regulatory and commercial milestones associated with SB206 or any product that incorporates or uses NVN1000, the active pharmaceutical ingredient for the Company’s clinical stage product candidates, for the treatment of molluscum contagiosum. In addition to the milestone payments, the Company will pay Ligand tiered royalties ranging from 7% to 10% based on annual aggregate net sales of such products in the United States, Mexico or Canada. The Company has determined that the Ligand transaction is within the scope of ASC 730-20 as it represents an obligation to perform contractual services for the development of SB206 using commercially reasonable efforts. In addition, the Funding Agreement also states that if all development of SB206 is ceased prior to the first regulatory approval, the Company must pay to Ligand an amount equal to the purchase price less the amount spent in accordance with the development budget on development activities conducted prior to such cessation. As such, the Company has concluded that the appropriate accounting treatment under ASC 730-20 is to record the initial proceeds of $12,000 , as a liability and as restricted cash on its consolidated balance sheet, as the funds can only be used for the progression of SB206. The Company amortizes the liability ratably during each reporting period, based on the Ligand funding as a percentage of the total direct costs incurred by the Company during the reporting period related to the estimated total cost to progress the SB206 program to a regulatory approval in the U.S. The ratable Ligand funding is presented within the consolidated statement of operations as an offset to research and development expenses associated with the SB206 program. During the first quarter of 2020, the Company expects to reassess the estimated total cost to progress the SB206 program to a U.S. regulatory approval, as the Company considers how such estimated costs may potentially be affected by various factors, including (i) the recent results from the Company’s SB206 Phase 3 trials in the U.S., including but not limited to top-line efficacy results announced in January 2020, (ii) the Company’s plans and timelines for potential further clinical development of SB206 in the U.S., which is subject to additional funding and feedback from a Type C meeting with the FDA scheduled for April 1, 2020, and (iii) the Company’s in-house drug manufacturing capabilities and the progression of the Company’s manufacturing technology transfer projects with third-party contract manufacturing organizations. The initial restricted cash balance was also reduced ratably during interim reporting periods in 2019 in a manner consistent with the amortization method for the Ligand funding liability balance. As of December 31, 2019, the aggregate amount spent in accordance with the SB206 development budget on SB206 development activities had exceeded the $12,000 purchase price, causing the aforementioned repayment provision provided for in the Funding Agreement to no longer be enforceable. Therefore, the Company reported no restricted cash balance related to the Funding Agreement, as of December 31, 2019 in its consolidated balance sheet. For the year ended December 31, 2019 , the Company recorded $8,185 as contra-research and development expense related to the SB206 developmental program, funded by Ligand.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment consisted of the following: December 31, 2019 2018 Computer equipment $ 575 $ 577 Furniture and fixtures 305 312 Laboratory equipment 7,898 7,442 Office equipment 339 400 Building related to facility lease obligation — 10,557 Leasehold improvements 7,068 1,168 Property and equipment, gross 16,185 20,456 Less: Accumulated depreciation and amortization (5,679 ) (4,588 ) Total property and equipment, net $ 10,506 $ 15,868 Depreciation and amortization expense was $2,033 and $1,664 for the years ended December 31, 2019 and 2018 , respectively. See Note 1—Organization and Significant Accounting Policies and Note 8—Commitments and Contingencies regarding the adoption of Topic 842, Leases , and its impact to property and equipment, net for the year ended December 31, 2019 .

Commitment and Contingencies

Commitment and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Obligations The Company leases office space and certain equipment under non-cancelable lease agreements. Prior to January 1, 2019, the Company applied the accounting guidance in ASC 840, Leases , to its lease agreements. The leases were reviewed for classification as operating or capital leases. For operating leases, rent was recognized on a straight-line basis over the lease period. For capital leases, the Company recorded the leased asset with a corresponding liability and amortized the asset over the lease term. Payments were recorded as reductions to the liability with an appropriate interest charge recorded based on the then-outstanding remaining liability. The Company considered the nature of the renovations and the Company’s involvement during the construction period of previously leased office space to determine if it was considered to be the owner of the construction project during the construction period. If the Company determined that it was the owner of the construction project, it was required to capitalize the fair value of the building as well as the construction costs incurred, including capitalized interest, on its consolidated balance sheet along with a corresponding financing liability (“build-to-suit accounting”). Upon completion of the construction of the facility under a build-to-suit lease, the Company assessed whether the circumstances qualified for sales recognition under the sale-leaseback accounting guidance. If the lease met the sale-leaseback criteria, the Company would remove the asset and related financial obligation from the balance sheet and evaluate the lease for treatment as a capital or operating lease. If upon completion of construction, the project did not meet the sale-leaseback criteria, the leased property was treated as an asset financing for financial reporting purposes. The portion of the facility financing obligation representing the principal that was to be repaid in the following 12 months was classified as a current liability in the consolidated balance sheets, with the remaining portion of the obligation classified as a noncurrent liability. Beginning January 1, 2019, the Company applies the accounting guidance in ASC 842, Leases. As such, the Company assesses all arrangements, that convey the right to control the use of property, plant and equipment, at inception, to determine if it is, or contains, a lease based on the unique facts and circumstances present in that arrangement. For those leases identified, the Company determines the lease classification, recognition, and measurement at the lease commencement date. For arrangements that contain a lease the Company: (i) identifies lease and non-lease components; (ii) determines the consideration in the contract; (iii) determines whether the lease is an operating or financing lease; and (iv) recognizes lease ROU assets and corresponding lease liabilities. Lease liabilities are recorded based on the present value of lease payments over the expected lease term. The corresponding ROU asset is measured from the initial lease liability, adjusted by (i) accrued or prepaid rents; (ii) remaining unamortized initial direct costs and lease incentives; and (iii) any impairments of the ROU asset. The interest rate implicit in the Company’s lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. The weighted average discount rate utilized on the Company’s operating lease liabilities as of December 31, 2019 was 9.85% . The weighted average remaining lease term for the Company’s operating leases as of December 31, 2019 was 6.50 years . Primary Facility Lease In August 2015, the Company entered into a lease agreement for approximately 51,000 rentable square feet of facility space in Morrisville, North Carolina, commencing in April 2016 (the “Primary Facility Lease”). The initial term of the Primary Facility Lease extends through June 30, 2026 . The Company has an option to extend the Primary Facility Lease by five years upon completion of the initial lease term, however, the renewal period was not included in the calculation of the lease obligation. Current contractual base rent payments are $95 per month, subject to a three percent increase annually over the term of the Primary Facility Lease. Prior to January 1, 2019, the Company applied the accounting guidance in ASC 840. Based on that guidance, the facility was accounted for as an asset financing, with the building asset and related facility financing obligation remaining on the Company’s balance sheet. The building asset was being depreciated over a 25 year period and the facility financing obligation was amortized so that the net carrying value of the building asset and the facility financing obligation were to be equivalent at the end of the initial term of the lease agreement. Monthly rental payments were allocated between principal and interest expense associated with the facility financing obligation, as well as grounds rent expense of $8 per month. The Company had recorded an asset related to the building and construction costs within property and equipment of $10,557 as of December 31, 2018 . The non-current facility lease obligation on the Company’s consolidated balance sheet was $7,998 as of December 31, 2018 . During the year ended December 31, 2018 , the Company recognized interest expense related to the primary facility lease of $1,044 and there was $ 41 of accrued interest included in other accrued expenses as of December 31, 2018 The Company adopted Topic 842 as of January 1, 2019 using the modified retrospective transition method and initially applied the transition provisions as of January 1, 2019. This transition method allowed the Company to continue to apply the legacy guidance in ASC 840 for periods prior to 2019 and recognize a cumulative-effect adjustment to the opening balance of accumulated deficit as of the date of adoption. The Company elected the package of transition practical expedients, which, among other things, allowed the Company to keep the historical lease classifications and not have to reassess the lease classification for any existing leases as of the date of adoption. The Company also made an accounting policy election to apply the short-term lease exception, which allows the Company to exclude leases with an initial term of twelve months or less from the consolidated balance sheets. As a result of the adoption of Topic 842, the Company derecognized $10,557 of building asset (property, plant and equipment), and $7,998 of facility financing obligation associated with previously existing build-to-suit arrangement related to its sole corporate and manufacturing facility. The Company also capitalized leasehold improvements and ROU assets of $5,885 and $1,827 , respectively, and recorded lease liabilities for operating leases totaling $6,786 , as of January 1, 2019. The capitalized leasehold improvement assets recorded as part of the adoption of Topic 842 were previously included within the derecognized building asset as part of the previous build-to-suit arrangement. The Company also recognized an increase of $714 to accumulated deficit related to its de-recognition of its previously recorded build-to-suit arrangement. The Company has elected to separate lease components (fixed rent payments) with non-lease components (common-area maintenance costs) on its real estate assets. Fixed lease payments on operating leases are recognized over the expected term of the lease on a straight-line basis. Variable lease expenses that are not considered fixed are expensed as incurred. Fixed and variable lease expense on operating leases is recognized within operating expenses within our consolidated statements of operations. The Company has elected the short-term lease exemption and, therefore, does not recognize a ROU asset or corresponding liability for lease arrangements with an original term of 12 months or less. Rent expense, including both short-term and variable lease components associated with the primary facility lease, was $880 and $308 for the years ended December 31, 2019 and 2018 , respectively. The Company’s supplemental non-cash disclosure for its ROU assets obtained in exchange for lease liabilities was $1,827 for the year ended December 31, 2019 . At December 31, 2019 , maturities of operating lease liabilities over each of the next five years and thereafter are as follows: Operating Leases 2020 $ 1,215 2021 1,241 2022 1,278 2023 1,317 2024 1,356 Thereafter 2,111 Total minimum lease payments $ 8,518 Less imputed interest $ (2,256 ) Total lease liability $ 6,262 Primary Facility Sublease In July 2018, the Company and a third-party tenant commenced a sublease of approximately 6,400 square feet of office space at the Company’s headquarters. The sublease has a three -year, non-cancellable term and provides for monthly rental income to the Company of approximately $12 per month through July 2021. The Company has classified the sublease as an operating lease pursuant to classification criteria in ASC 842 and is recognizing the rental income on a straight-line basis over the lease term as a component of other income and expense in the Company’s consolidated statements of operations and comprehensive loss. In October 2019, the Company executed a termination agreement with the subtenant for this sublease, with an effective date of December 31, 2019. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. See Legal Proceedings below for further discussion of pending legal claims. The Company has entered into, and expects to continue to enter into, contracts in the normal course of business with various third parties who support its clinical trials, preclinical research studies and other services related to its development activities. The scope of the services under these agreements can generally be modified at any time, and these agreements can generally be terminated by either party after a period of notice and receipt of written notice. There have been no material contract terminations as of December 31, 2019 . See Note 3—Research and Development Licenses regarding the Company’s research and development license agreements. See Note 6—Research and Development Arrangements regarding the Purchase Agreement with Reedy Creek and the Funding Agreement with Ligand. Legal Proceedings In prior filings, the Company reported that it was subject to putative stockholder class action lawsuits that were filed in November 2017 in the United States District Court for the Middle District of North Carolina against the Company and certain of its current and former directors and officers, which were consolidated under the case name In re Novan, Inc. Securities Litigation . The consolidated amended complaint filed by the designated lead plaintiff asserted claims for violation of Sections 11 and 15 of the Securities Act of 1933 and Sections 10(b) and 20(a) of the Exchange Act and SEC Rule 10b-5 promulgated thereunder, in connection with statements related to the Company’s Phase 3 clinical trials of SB204. On June 14, 2018, the Company filed a motion to dismiss the consolidated amended complaint. On November 30, 2018, a federal magistrate judge entered an order recommending that the district court grant the Company’s motion. The plaintiff filed objections to this recommendation and the Company filed a response. On January 28, 2019, the district court adopted the magistrate judge’s recommendation, dismissed the action with prejudice and entered judgment in favor of the Company and against the plaintiff. The plaintiff did not appeal this dismissal and judgment. As such, the Company has concluded that this matter is closed. Other than as described above, the Company is not currently a party to any material legal proceedings and is not aware of any claims or actions pending or threatened against the Company that the Company believes could have a material adverse effect on the Company’s business, operating results, cash flows or financial statements. In the future, the Company might from time to time become involved in litigation relating to claims arising from its ordinary course of business. Compensatory Obligations In conjunction with the departures of three former Company officers in 2019 and 2018, the Company entered into separation and general release agreements that included separation benefits consistent with the Company’s obligations under their previously existing employment agreements for “separation from service” for “good reason.” The Company recognized related severance expense of $878 and $332 during the years ended December 31, 2019 and 2018 , respectively. The remaining accrued severance obligation in respect of the three former officers was $33 as of December 31, 2019 , which is included in accrued compensation in the accompanying consolidated balance sheet. The Company also recognized non-cash stock compensation expense of $212 during the year ended December 31, 2018 , respectively, related to the accelerated vesting of the former officers’ stock options. There was no non-cash stock compensation expense in relation to these departures during the year ended December 31, 2019 . In November 2018, the Company realigned its overall employee headcount to reduce certain fixed costs. The Company recognized related severance expense of $67 and $196 during the years ended December 31, 2019 and 2018, respectively. As of December 31, 2019 , severance costs of $52 were accrued in the accompanying consolidated balance sheet. See “Note 11—Share-Based Compensation” regarding the SARs granted in August 2018. See “Note 12—Tangible Stockholder Return Plan” regarding the Tangible Stockholder Return Plan adopted in August 2018.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Capital Structure In conjunction with the completion of the Company’s initial public offering in September 2016, the Company further amended its amended and restated certificate of incorporation and amended and restated its bylaws. The amendment provides for 210,000,000 authorized shares of capital stock, of which 200,000,000 shares have been designated as $0.0001 par value common stock, and 10,000,000 shares have been designated as $0.0001 par value preferred stock. Aspire Common Stock Purchase Agreement On August 30, 2019, the Company entered into the Aspire Common Stock Purchase Agreement with Aspire Capital, which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $25,000 of shares of the Company’s common stock at the Company’s request from time to time during the 30 -month term of the Purchase Agreement. Concurrently with entering into the Purchase Agreement, the Company also entered into a registration rights agreement with Aspire Capital (the “Registration Rights Agreement”), in which the Company agreed to file one or more registration statements, as permissible and necessary to register under the Securities Act of 1933, as amended (the “Securities Act”), registering the sale of the shares of the Company’s common stock that have been and may be issued to Aspire Capital under the Aspire Common Stock Purchase Agreement. On September 16, 2019, the Company filed with the SEC, a prospectus to the effective Registration Statement on Form S-1 (File No. 333-233632) registering 7,032,630 shares of common stock that have been and may be offered to Aspire Capital from time to time under the Aspire Common Stock Purchase Agreement. Under the Aspire Common Stock Purchase Agreement, on any trading day selected by the Company, the Company has the right, in its sole discretion, to present Aspire Capital with a purchase notice (each, a “Purchase Notice”), directing Aspire Capital (as principal) to purchase up to 100,000 shares of the Company’s common stock per business day, up to $25,000 of the Company’s common stock in the aggregate at a per share price (the “Purchase Price”) equal to the lesser of (i) the lowest sale price of the Company’s common stock on the purchase date, or (ii) the arithmetic average of the three (3) lowest closing sale prices for the Company’s common stock during the ten (10) consecutive trading days ending on the trading day immediately preceding the purchase date. The aggregate purchase price payable by Aspire Capital on any one purchase date may not exceed $500 . In addition, on any date on which the Company submits a Purchase Notice to Aspire Capital in an amount equal to 100,000 shares, the Company also has the right, in its sole discretion, to present Aspire Capital with a volume-weighted average price purchase notice (each, a “VWAP Purchase Notice”) directing Aspire Capital to purchase an amount of stock equal to up to 30% of the aggregate shares of the Company’s common stock traded on its principal market on the next trading day (the “VWAP Purchase Date”), subject to a maximum number of shares the Company may determine. The purchase price per share pursuant to such VWAP Purchase Notice is generally 97% of the volume-weighted average price for the Company’s common stock traded on its principal market on the VWAP Purchase Date. The Purchase Price will be adjusted for any reorganization, recapitalization, non-cash dividend, stock split, or other similar transaction occurring during the period(s) used to compute the Purchase Price. The Company may deliver multiple Purchase Notices and VWAP Purchase Notices to Aspire Capital from time to time during the term of the Aspire Common Stock Purchase Agreement, so long as the most recent purchase has been completed. The Aspire Common Stock Purchase Agreement provides that the Company and Aspire Capital shall not effect any sales under the Aspire Common Stock Purchase Agreement on any purchase date where the closing sale price of the Company’s common stock is less than $0.25 . There are no trading volume requirements or restrictions under the Aspire Common Stock Purchase Agreement, and the Company will control the timing and amount of sales of the Company’s common stock to Aspire Capital. Aspire Capital has no right to require any sales by the Company, but is obligated to make purchases from the Company as directed by the Company in accordance with the Aspire Common Stock Purchase Agreement. There are no limitations on use of proceeds, financial or business covenants, restrictions on future financing transactions, rights of first refusal, participation rights, penalties or liquidated damages in the Aspire Common Stock Purchase Agreement. The Aspire Common Stock Purchase Agreement may be terminated by the Company at any time, at its discretion, without any penalty or additional cost to the Company. Aspire Capital has agreed that neither it nor any of its agents, representatives and affiliates shall engage in any direct or indirect short-selling or hedging of the Company’s common stock during any time prior to the termination of the Aspire Common Stock Purchase Agreement. Any proceeds the Company receives under the Aspire Common Stock Purchase Agreement are expected to be used for working capital and general corporate purposes. The Aspire Common Stock Purchase Agreement provides that the number of shares that may be sold pursuant to the Aspire Common Stock Purchase Agreement will be limited to 5,211,339 shares (the “Exchange Cap”), which represents 19.99% of the Company’s outstanding shares of common stock on August 30, 2019, unless stockholder approval or an exception pursuant to the rules of the Nasdaq Global Market is obtained to issue more than 19.99% . This limitation will not apply if, at any time the Exchange Cap is reached and at all times thereafter, the average price paid for all shares issued under the Aspire Common Stock Purchase Agreement is equal to or greater than $2.17 , which was the closing sale price of the Company’s common stock immediately preceding the execution of the Aspire Common Stock Purchase Agreement. The Company is not required or permitted to issue any shares of common stock under the Aspire Common Stock Purchase Agreement if such issuance would breach its obligations under the rules or regulations of the Nasdaq Global Market. The Company may, in its sole discretion, determine whether to obtain stockholder approval to issue more than 19.99% of its outstanding shares of Common Stock hereunder if such issuance would require stockholder approval under the rules or regulations of the Nasdaq Global Market. In consideration for entering into the Aspire Common Stock Purchase Agreement, concurrently with the execution of the Aspire Common Stock Purchase Agreement, the Company issued to Aspire Capital 345,622 shares of the Company’s common stock (the “Commitment Shares”). These Commitment Shares valued at $750 were recorded in August 2019 as non-cash costs of equity financing and charged against additional paid-in capital. As of December 31, 2019 , the Company has sold 300,000 shares of common stock at an average price of $2.49 per share under the Aspire Common Stock Purchase Agreement. The Company has remaining availability for sales of its common stock under the Aspire Common Stock Purchase Agreement, subject to the limitations described above, of up to $24,253 as of December 31, 2019 . January 2018 Offering On January 9, 2018, the Company completed a public offering of its common stock and warrants pursuant to the Company’s effective shelf registration statement (the “January 2018 Offering”). The Company sold an aggregate of 10,000,000 shares of common stock and warrants to purchase up to 10,000,000 shares of the Company’s common stock at a public offering price of $3.80 per share of common stock and accompanying warrant. The warrant exercise price is $4.66 per share and will expire four years from the date of issuance. Net proceeds from the offering were approximately $35,194 after deducting underwriting discounts and commissions and offering expenses of approximately $2,806 . The Company incurred costs directly related to (i) the shelf registration statement filing totaling $110 and (ii) the January 2018 Offering completed in January 2018 totaling $370 , all of which were initially capitalized and included in deferred offering costs. A pro-rata portion of the shelf registration offering costs and all of the January 2018 Offering costs were reclassified to additional paid-in capital upon completion of the January 2018 Offering. Common Stock The Company’s common stock has a par value of $0.0001 per share and consists of 200,000,000 authorized shares as of December 31, 2019 and 2018 . There were 26,734,800 and 26,056,735 shares of common stock outstanding as of December 31, 2019 and 2018 , respectively. The Company had reserved shares of common stock for future issuance as follows: December 31, 2019 2018 Outstanding stock options (Note 11) 1,789,303 1,671,666 Warrants to purchase common stock issued in January 2018 Offering 10,000,000 10,000,000 Outstanding stock appreciation rights (Note 11) 1,000,000 — For possible future issuance under 2016 Stock Plan (Note 11) 388,463 699,376 13,177,766 12,371,042 Related Party Stock Repurchase In April 2016, the Company repurchased 9,500 shares of common stock for an aggregate price of $155 from an executive of the Company who was also a member of the Company’s board of directors at that time. The repurchase of these shares is recorded as treasury stock on the Company’s consolidated balance sheet as of December 31, 2019 and 2018 . Preferred Stock The Company’s amended and restated certificate of incorporation provides the Company’s board of directors with the authority to issue $0.0001 par value preferred stock from time to time in one or more series by adopting a resolution and filing a certificate of designations. Voting powers, designations, preferences, dividend rights, conversion rights and liquidation preferences shall be stated and expressed in such resolutions. There were 10,000,000 shares designated as preferred stock and no shares outstanding as of December 31, 2019 and 2018 .

Warrants

Warrants	12 Months Ended
	Dec. 31, 2019
Warrants and Rights Note Disclosure [Abstract]
Warrants	Warrants The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level in which to classify them for each reporting period, pursuant to the fair value measurements policy described in “Note 1—Organization and Significant Accounting Policies.” This determination requires significant judgments to be made. On January 9, 2018, the Company sold an aggregate of 10,000,000 shares of common stock and issued warrants to purchase up to 10,000,000 shares of common stock at a public offering price of $3.80 per share of common stock and accompanying warrant. Pursuant to the warrant agreement and form of warrant dated January 9, 2018 (the “Warrant Agreement”), the warrant exercise price is $4.66 per share and the warrants will expire four years from the date of issuance. The Warrant Agreement includes a provision whereby the exercisability of the warrants may be limited if, upon exercise, the warrant holder or any of its affiliates would beneficially own more than 4.99% (or an amount up to 9.99% if the holder so elects) of the Company’s common stock. The Warrant Agreement also provides that the aforementioned exercise limitation provision is not applicable to any warrant holder that beneficially owns 10.0% or more of the Company’s outstanding common stock immediately following the closing of the January 2018 Offering and the issuance of the accompanying warrants. If, at any time the warrants are outstanding, any fundamental transaction occurs, as described in the Warrant Agreement and generally including any consolidation or merger whereby another entity acquires more than 50% of the Company’s outstanding common stock, or the sale of all or substantially all of its assets, the successor entity must assume in writing all of the obligations to the warrant holders. Additionally, in the event of a fundamental transaction, the Warrant Agreement provides that each warrant holder will have the right to require the Company, or its successor, to repurchase the warrants for an amount of cash equal to the Black-Scholes value of the remaining unexercised portion of the warrants. Further, the Warrant Agreement states that the volatility input used to derive such Black-Scholes value is the greater of the Company’s historical volatility or 100% . Due to the provision that the warrant holder has the option to receive a cash settlement, equal to the Black-Scholes fair value of the remaining unexercised portion of the warrant, in the event that there is a fundamental transaction, the Company has classified the warrants as liabilities in accordance with ASC 480, Distinguishing Liabilities from Equity . There were no exercises of warrants during the year ended December 31, 2019 . The following table presents the Company’s warrant liability measured at fair value on a recurring basis as of December 31, 2019 and 2018: December 31, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Liabilities: Warrant liability $ — $ — $ 1,504 $ 1,504 Total liabilities at fair value $ — $ — $ 1,504 $ 1,504 December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Liabilities: Warrant liability $ — $ — $ 1,240 $ 1,240 Total liabilities at fair value $ — $ — $ 1,240 $ 1,240 The fair value of the common stock warrants is estimated using a valuation model that approximates a Monte Carlo simulation model, which takes into consideration the probability of a fundamental transaction occurring during the contractual term of the warrants. This valuation model, which includes inputs classified as Level 3 in the fair value hierarchy, estimated a fair value of $0.15 and $0.12 per common stock warrant as of December 31, 2019 and 2018, respectively. The fair value of warrants falls within Level 3 of the hierarchy as there is currently no active trading market. The inputs to the valuation model that approximates a Monte Carlo simulation model are presented below. December 31, 2019 2018 Estimated dividend yield — — Expected volatility 100% - 101.73% 77.74%-100% Risk-free interest rate 1.58 % 2.46 % Expected term (years) 2.03 3.02 Fair value per share of common stock underlying the warrant $ 0.86 $ 0.83 Warrant exercise price $ 4.66 $ 4.66 Due to the Company’s limited historical stock price data, the Company estimates stock price volatility based on the actual historical volatility of a group of comparable publicly traded companies observed over a historical period equal to the expected life of the warrant. The increase in fair value of the warrants of $264 and decrease in fair value of the warrants of $16,566 for the years ended December 31, 2019 and 2018, respectively, are included as components of other income and expense in the Company’s consolidated statements of operations and comprehensive loss. The change in the warrant liability and the corresponding unrealized loss/gain recognized during the years ended December 31, 2019 and 2018, respectively, is primarily due to the fluctuations in the market price of the Company’s underlying common stock from the date of issuance, in addition to fluctuations in the other valuation model inputs. The following table summarizes the change in the fair value of the warrant liability, which is valued using significant unobservable Level 3 inputs, for the years ended December 31, 2019 and 2018: December 31, 2019 2018 Beginning Balance $ 1,240 $ — Issuance $ — $ 17,806 Revaluations Included In Earnings $ 264 $ (16,566 ) Exercises $ — $ — Expirations $ — $ — Ending Balance $ 1,504 $ 1,240

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation 2008 Stock Plan During 2008, the Company adopted the 2008 Stock Plan (the “2008 Plan”). As amended, a total of 1,416,666 shares of common stock were reserved for issuance under the 2008 Plan. Eligible plan participants included employees, directors, and consultants. The 2008 Plan permitted the granting of incentive stock options, nonqualified stock options, and other stock-based awards. As further described below, as of September 20, 2016, no additional awards will be granted under the 2008 Plan. 2016 Stock Plan Effective September 20, 2016 (the “Effective Date”), the Company adopted the 2016 Incentive Award Plan (the “2016 Plan”). The 2016 Plan is the successor to the 2008 Plan. As of the Effective Date, no additional awards will be granted under the 2008 Plan, but all stock awards granted under the 2008 Plan prior to the Effective Date will remain subject to the terms of the 2008 Plan. Any shares associated with stock awards previously granted under the 2008 Plan that are forfeited subsequent to the Effective Date of the 2016 Plan are not eligible for future issuance under the 2016 Plan. All awards granted on and after the Effective Date will be subject to the terms of the 2016 Plan. The 2016 Plan provides for the grant of the following awards: (i) incentive stock options, (ii) nonstatutory stock options, (iii) SARs, (iv) restricted stock awards, (v) restricted stock unit awards and (vi) other stock awards. Eligible plan participants include employees, directors, and consultants. An aggregate of 833,333 shares of the Company’s common stock were initially available for issuance under awards granted pursuant to the 2016 Plan, which shares may be authorized but unissued shares, treasury shares, or shares purchased in the open market. On June 5, 2017, the Company’s stockholders approved an amendment to the 2016 Plan to increase the aggregate number of shares of common stock that may be issued pursuant to awards under the 2016 Plan by an additional 1,200,000 shares. All other material terms of the 2016 Plan otherwise remained unchanged. On July 31, 2019, the Company’s stockholders approved an amendment to the 2016 Plan (“the 2016 Plan Amendment”), to increase the number of shares reserved under the 2016 Plan by 1,000,000 and to increase the award limit on the maximum aggregate number of shares of the Company’s common stock that may be granted to any one person during any calendar year from 250,000 to 1,000,000 shares of the Company’s common stock. All other material terms of the 2016 Plan otherwise remain unchanged. As of December 31, 2019 , there were 388,463 shares available for future issuance under the 2016 Plan. Under both the 2008 Plan and the 2016 Plan, options to purchase the Company’s common stock may be granted at a price no less than the fair value of a common stock share on the date of grant. The fair value shall be the closing sales price for a share as quoted on any established securities exchange for such grant date or the last preceding date for which such quotation exists. Vesting terms of options issued are determined by the board of directors or compensation committee of the board. The Company’s stock options vest based on terms in the stock option agreements and have a maximum term of ten years . Stock Appreciation Rights On August 8, 2018, the Company entered into an employment agreement with G. Kelly Martin (the “Martin Employment Agreement”). The Martin Employment Agreement provided for 1,000,000 SARs (the “Martin SAR Award”) granted on a contingent basis that would have been irrevocably forfeited and voided in full if the Company had failed to obtain stockholder approval for the 2016 Plan Amendment. If such approval had not been obtained, the Company would have been required to pay Mr. Martin the cash equivalent of the value of the SARs. Following stockholder approval of the 2016 Plan Amendment, the SARs detailed within the Martin Employment Agreement were no longer considered to be granted on a contingent basis. The SARs entitle Mr. Martin to a payment (in cash, shares of common stock or a combination of both) equal to the fair market value of one share of the Company’s common stock on the date of exercise less the exercise price of $3.80 per share. The SARs will be deemed automatically exercised and settled as of February 1, 2020 , provided Mr. Martin remains continuously employed with the Company through such date unless vesting is otherwise expressly accelerated pursuant to the Martin SAR Award. Due to the contingent nature of the SAR grant, prior to stockholder approval on July 31, 2019, these share-based payment awards were classified as liabilities and the amount of compensation cost recognized was based on the fair value of those liabilities. The corresponding obligation was recorded within other long-term liabilities on the Company’s consolidated balance sheet at the estimated fair value on the date of issuance and was re-valued each subsequent reporting period with adjustments to the fair value recognized as share-based compensation expense in the consolidated statements of operations. As the Company has the sole discretion to settle any awards with cash, common stock or a combination of both, subsequent to stockholder approval as of July 31, 2019, the SARs were reclassified from liability to equity-based awards at fair value and reclassified to additional paid-in capital. The fair value of the SARs was estimated using the Black-Scholes option pricing model on the July 31, 2019 remeasurement date. The reclassification from other long-term liabilities to additional paid-in capital in the consolidated balance sheet was $366 as of July 31, 2019. The fair value of the SARs was estimated using the Black-Scholes option-pricing model for the respective periods, using the following assumptions: July 31, 2019 December 31, 2018 Estimated dividend yield — — Expected volatility 115.82 % 86.71 % Risk-free interest rate 2.07 % 2.63 % Expected term (years) 0.51 1.09 Fair value per share of common stock underlying the SAR $ 2.66 $ 0.83 SAR exercise price $ 3.80 $ 3.80 During the years ended December 31, 2019 and 2018 , the Company recorded employee share-based compensation expense related to the SARs of $507 and $8 , respectively. As of December 31, 2019 , total unrecognized compensation expense related to non-vested SARs was $33 , which is expected to be fully recognized by the February 1, 2020 vesting date. As described in Note 16—Subsequent Events, on February 1, 2020, the fair market value of our common stock was $0.52 per share. As a result, the SARs expired unexercised and 1,000,000 shares became available for grant under the 2016 Plan. Inducement Grants During the years ended December 31, 2019 and 2018 , the Company awarded nonstatutory stock options to purchase shares of common stock to newly-hired employees, not previously employees or directors of the Company, as inducements material to the individuals’ entering into employment with the Company within the meaning of Nasdaq Listing Rule 5635(c)(4) (the “Inducement Grants”). On May 31, 2018, the Company awarded 100,500 Inducement Grants with an exercise price of $3.15 per share, and on September 6, 2019, the Company awarded 25,000 Inducement Grants with an exercise price of $2.62 per share. The Inducement Grants were awarded outside of the Company’s 2016 Plan, pursuant to Nasdaq Listing Rule 5635(c)(4), but have terms and conditions generally consistent with the Company’s 2016 Plan and vest over three years, subject to the employee’s continued service as an employee or consultant through the vesting period. Stock Compensation Expense During the years ended December 31, 2019 and 2018 , the Company recorded employee share-based compensation expense of $1,838 and $2,204 , respectively. Total share-based compensation expense included in the consolidated statements of operations is as follows: Year Ended December 31, 2019 2018 Research and development $ 710 $ 1,144 General and administrative 1,128 1,060 $ 1,838 $ 2,204 The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, and the following weighted average assumptions: Year Ended December 31, 2019 2018 Estimated dividend yield 0.00 % 0.00 % Expected volatility 102.14 % 81.73 % Risk-free interest rate 1.87 % 2.75 % Expected life of options (in years) 5.20 5.68 Weighted-average fair value per share $ 1.77 $ 2.06 Stock option activity for the periods indicated is as follows: Shares Available for Grant Shares Subject to Outstanding Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Options outstanding as of December 31, 2017 1,023,378 1,399,484 $ 7.17 Additional shares reserved under plan — — Options granted (626,757 ) 727,257 2.97 Options forfeited 302,755 (403,748 ) 7.61 Options exercised — (51,327 ) 1.16 Options outstanding as of December 31, 2018 699,376 1,671,666 $ 5.42 Options granted (633,030 ) 658,030 2.36 Options forfeited 322,117 (507,950 ) 7.07 Options exercised — (32,443 ) 2.12 Options outstanding as of December 31, 2019 388,463 1,789,303 $ 3.89 8.03 $ 638 Vested and expected to vest as of 1,585,689 $ 5.53 8.11 $ 2 Exercisable as of December 31, 2018 1,007,870 $ 6.58 7.54 $ 2 Vested and expected to vest as of 1,731,437 $ 3.94 7.99 $ 597 Exercisable as of December 31, 2019 1,032,801 $ 4.81 7.20 $ 190 The total intrinsic value of options exercised during the years ended December 31, 2019 and 2018 was $15 and $95 , respectively. As of December 31, 2019 and 2018 , total unrecognized compensation expense related to non-vested stock options was $965 and $1,036 , respectively, which is expected to be recognized over a weighted average period of 0.99 and 1.79 years, respectively. Tangible Stockholder Return Plan Performance Plan On August 2, 2018, the Company’s board of directors approved and established the Tangible Stockholder Return Plan, which is a performance-based long-term incentive plan (the “Performance Plan”). The Performance Plan was effective immediately upon approval and expires on March 1, 2022 . The Performance Plan covers all employees, including the Company’s executive officers, consultants and other persons deemed eligible by the Company’s compensation committee. The core underlying metric of the Performance Plan is the achievement of two share price goals for the Company’s common stock, which if achieved, would represent measurable increases in stockholder value. The Performance Plan is tiered, with two separate tranches, each of which has a distinct share price target (measured as the average publicly traded share price of the Company’s common stock on the Nasdaq stock exchange for a 30 consecutive trading day period) that will, if achieved, trigger a distinct fixed bonus pool. The share price target for the first tranche and related bonus pool are $11.17 per share and $25,000 , respectively. The share price target for the second tranche and related bonus pool are $25.45 per share and $50,000 , respectively. The compensation committee has discretion to distribute the bonus pool related to each tranche among eligible participants by establishing individual minimum bonus amounts before, as well as by distributing the remainder of the applicable pool after, the achievement of each tranche specific share price target. Otherwise, if the Company does not achieve one or both related share price targets, as defined, no portion of the bonus pools will be paid. The Performance Plan provides for the distinct fixed bonus pools to be paid in the form of cash. However, the compensation committee has discretion to pay any bonus due under the Performance Plan in the form of cash, shares of the Company’s common stock or a combination thereof, provided that the Company’s stockholders have approved the reservation of shares of the Company’s common stock for such payment. The Performance Plan permits the compensation committee to make bonus awards subject to varying payment terms, including awards that vest and are payable immediately upon achieving an applicable share price target as well as awards that pay over an extended period (either with or without ongoing employment requirements). The Performance Plan contemplates that no bonus award payments will be delayed beyond 24 months for named executive officers or more than 12 months for all other participants. For purposes of determining whether a share price target has been met, the share price targets will be adjusted in the event of any stock splits, cash dividends, stock dividends, combinations, reorganizations, reclassifications or similar events. In the event of a change in control, as defined in the Performance Plan, during the term of the Performance Plan, a performance bonus pool will become due and payable to participants on a pro rata basis, as calculated and determined by the compensation committee based upon the Company’s progress toward the share price target as of the date of the change in control and subject to adjustment by the compensation committee as permitted under the Performance Plan. The Company has concluded that the Performance Plan is within the scope of ASC 718 , Compensation — Stock Compensation as the underlying plan obligations are based on the potential attainment of certain market share price targets of the Company’s common stock. Any awards under the Performance Plan would be payable, at the discretion of the Company’s compensation committee following the achievement of the applicable share price target, in cash, shares of the Company’s common stock, or a combination thereof, provided that, prior to any payment in common stock, the Company’s stockholders have approved the reservation of shares of the Company’s common stock for such payment. ASC 718 requires that a liability-based award should be classified as a liability on the Company’s consolidated balance sheets and the amount of compensation cost recognized should be based on the fair value of the liability. When a liability-based award includes both a service and market condition, the market condition is taken into account when determining the appropriate method to estimate fair value and the compensation cost is amortized over the estimated service period. Therefore, the liability associated with the Performance Plan obligation is recorded within other long-term liabilities on the Company’s consolidated balance sheets at the estimated fair value on the date of issuance and is re-valued each subsequent reporting period end. The Company recognizes share-based compensation expense within operating expenses in the consolidated statements of operations, including adjustments to the fair value of the liability-based award, on a straight-line basis over the requisite service period. The fair value of obligations under the Performance Plan are estimated using a Monte Carlo simulation approach. The Company’s common stock price is simulated under the Geometric Brownian Motion framework under each simulation path. The other assumptions for the Monte Carlo simulation include the risk-free interest rate, estimated volatility and the expected term. Expected stock price volatility is based on the actual historical volatility of a group of comparable publicly traded companies observed over a historical period equal to the expected remaining life of the plan. The fair value of the underlying common stock is the published closing market price on the Nasdaq Global Market as of each reporting date, as adjusted for significant results, as necessary. The risk-free interest rate is based on the U.S. Treasury yield curve in effect on the date of valuation equal to the remaining expected life of the plan. The dividend yield percentage is zero because the Company does not currently pay dividends, nor does it intend to do so during the expected term of the plan. The expected life of bonus awards under the Performance Plan is assumed to be equivalent to the remaining contractual term based on the estimated service period including the service inception date of the plan participants and the contractual end of the Performance Plan. The fair value of the Performance Plan is estimated at each financial reporting date using the Monte Carlo simulation model and the following assumptions: December 31, 2019 2018 Estimated dividend yield — — Expected volatility 128.30 % 87.19 % Risk-free interest rate 1.53 % 2.47 % Expected term (years) 2.17 3.17 Fair value per share of common stock underlying the Performance Plan $ 0.86 $ 0.83 During the years ended December 31, 2019 and 2018, the Company recorded employee share-based compensation expense related to the Performance Plan of $291

Tangible Stockholder Return Pla

Tangible Stockholder Return Plan	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Tangible Shareholder Return Plan	Share-Based Compensation 2008 Stock Plan During 2008, the Company adopted the 2008 Stock Plan (the “2008 Plan”). As amended, a total of 1,416,666 shares of common stock were reserved for issuance under the 2008 Plan. Eligible plan participants included employees, directors, and consultants. The 2008 Plan permitted the granting of incentive stock options, nonqualified stock options, and other stock-based awards. As further described below, as of September 20, 2016, no additional awards will be granted under the 2008 Plan. 2016 Stock Plan Effective September 20, 2016 (the “Effective Date”), the Company adopted the 2016 Incentive Award Plan (the “2016 Plan”). The 2016 Plan is the successor to the 2008 Plan. As of the Effective Date, no additional awards will be granted under the 2008 Plan, but all stock awards granted under the 2008 Plan prior to the Effective Date will remain subject to the terms of the 2008 Plan. Any shares associated with stock awards previously granted under the 2008 Plan that are forfeited subsequent to the Effective Date of the 2016 Plan are not eligible for future issuance under the 2016 Plan. All awards granted on and after the Effective Date will be subject to the terms of the 2016 Plan. The 2016 Plan provides for the grant of the following awards: (i) incentive stock options, (ii) nonstatutory stock options, (iii) SARs, (iv) restricted stock awards, (v) restricted stock unit awards and (vi) other stock awards. Eligible plan participants include employees, directors, and consultants. An aggregate of 833,333 shares of the Company’s common stock were initially available for issuance under awards granted pursuant to the 2016 Plan, which shares may be authorized but unissued shares, treasury shares, or shares purchased in the open market. On June 5, 2017, the Company’s stockholders approved an amendment to the 2016 Plan to increase the aggregate number of shares of common stock that may be issued pursuant to awards under the 2016 Plan by an additional 1,200,000 shares. All other material terms of the 2016 Plan otherwise remained unchanged. On July 31, 2019, the Company’s stockholders approved an amendment to the 2016 Plan (“the 2016 Plan Amendment”), to increase the number of shares reserved under the 2016 Plan by 1,000,000 and to increase the award limit on the maximum aggregate number of shares of the Company’s common stock that may be granted to any one person during any calendar year from 250,000 to 1,000,000 shares of the Company’s common stock. All other material terms of the 2016 Plan otherwise remain unchanged. As of December 31, 2019 , there were 388,463 shares available for future issuance under the 2016 Plan. Under both the 2008 Plan and the 2016 Plan, options to purchase the Company’s common stock may be granted at a price no less than the fair value of a common stock share on the date of grant. The fair value shall be the closing sales price for a share as quoted on any established securities exchange for such grant date or the last preceding date for which such quotation exists. Vesting terms of options issued are determined by the board of directors or compensation committee of the board. The Company’s stock options vest based on terms in the stock option agreements and have a maximum term of ten years . Stock Appreciation Rights On August 8, 2018, the Company entered into an employment agreement with G. Kelly Martin (the “Martin Employment Agreement”). The Martin Employment Agreement provided for 1,000,000 SARs (the “Martin SAR Award”) granted on a contingent basis that would have been irrevocably forfeited and voided in full if the Company had failed to obtain stockholder approval for the 2016 Plan Amendment. If such approval had not been obtained, the Company would have been required to pay Mr. Martin the cash equivalent of the value of the SARs. Following stockholder approval of the 2016 Plan Amendment, the SARs detailed within the Martin Employment Agreement were no longer considered to be granted on a contingent basis. The SARs entitle Mr. Martin to a payment (in cash, shares of common stock or a combination of both) equal to the fair market value of one share of the Company’s common stock on the date of exercise less the exercise price of $3.80 per share. The SARs will be deemed automatically exercised and settled as of February 1, 2020 , provided Mr. Martin remains continuously employed with the Company through such date unless vesting is otherwise expressly accelerated pursuant to the Martin SAR Award. Due to the contingent nature of the SAR grant, prior to stockholder approval on July 31, 2019, these share-based payment awards were classified as liabilities and the amount of compensation cost recognized was based on the fair value of those liabilities. The corresponding obligation was recorded within other long-term liabilities on the Company’s consolidated balance sheet at the estimated fair value on the date of issuance and was re-valued each subsequent reporting period with adjustments to the fair value recognized as share-based compensation expense in the consolidated statements of operations. As the Company has the sole discretion to settle any awards with cash, common stock or a combination of both, subsequent to stockholder approval as of July 31, 2019, the SARs were reclassified from liability to equity-based awards at fair value and reclassified to additional paid-in capital. The fair value of the SARs was estimated using the Black-Scholes option pricing model on the July 31, 2019 remeasurement date. The reclassification from other long-term liabilities to additional paid-in capital in the consolidated balance sheet was $366 as of July 31, 2019. The fair value of the SARs was estimated using the Black-Scholes option-pricing model for the respective periods, using the following assumptions: July 31, 2019 December 31, 2018 Estimated dividend yield — — Expected volatility 115.82 % 86.71 % Risk-free interest rate 2.07 % 2.63 % Expected term (years) 0.51 1.09 Fair value per share of common stock underlying the SAR $ 2.66 $ 0.83 SAR exercise price $ 3.80 $ 3.80 During the years ended December 31, 2019 and 2018 , the Company recorded employee share-based compensation expense related to the SARs of $507 and $8 , respectively. As of December 31, 2019 , total unrecognized compensation expense related to non-vested SARs was $33 , which is expected to be fully recognized by the February 1, 2020 vesting date. As described in Note 16—Subsequent Events, on February 1, 2020, the fair market value of our common stock was $0.52 per share. As a result, the SARs expired unexercised and 1,000,000 shares became available for grant under the 2016 Plan. Inducement Grants During the years ended December 31, 2019 and 2018 , the Company awarded nonstatutory stock options to purchase shares of common stock to newly-hired employees, not previously employees or directors of the Company, as inducements material to the individuals’ entering into employment with the Company within the meaning of Nasdaq Listing Rule 5635(c)(4) (the “Inducement Grants”). On May 31, 2018, the Company awarded 100,500 Inducement Grants with an exercise price of $3.15 per share, and on September 6, 2019, the Company awarded 25,000 Inducement Grants with an exercise price of $2.62 per share. The Inducement Grants were awarded outside of the Company’s 2016 Plan, pursuant to Nasdaq Listing Rule 5635(c)(4), but have terms and conditions generally consistent with the Company’s 2016 Plan and vest over three years, subject to the employee’s continued service as an employee or consultant through the vesting period. Stock Compensation Expense During the years ended December 31, 2019 and 2018 , the Company recorded employee share-based compensation expense of $1,838 and $2,204 , respectively. Total share-based compensation expense included in the consolidated statements of operations is as follows: Year Ended December 31, 2019 2018 Research and development $ 710 $ 1,144 General and administrative 1,128 1,060 $ 1,838 $ 2,204 The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, and the following weighted average assumptions: Year Ended December 31, 2019 2018 Estimated dividend yield 0.00 % 0.00 % Expected volatility 102.14 % 81.73 % Risk-free interest rate 1.87 % 2.75 % Expected life of options (in years) 5.20 5.68 Weighted-average fair value per share $ 1.77 $ 2.06 Stock option activity for the periods indicated is as follows: Shares Available for Grant Shares Subject to Outstanding Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Options outstanding as of December 31, 2017 1,023,378 1,399,484 $ 7.17 Additional shares reserved under plan — — Options granted (626,757 ) 727,257 2.97 Options forfeited 302,755 (403,748 ) 7.61 Options exercised — (51,327 ) 1.16 Options outstanding as of December 31, 2018 699,376 1,671,666 $ 5.42 Options granted (633,030 ) 658,030 2.36 Options forfeited 322,117 (507,950 ) 7.07 Options exercised — (32,443 ) 2.12 Options outstanding as of December 31, 2019 388,463 1,789,303 $ 3.89 8.03 $ 638 Vested and expected to vest as of 1,585,689 $ 5.53 8.11 $ 2 Exercisable as of December 31, 2018 1,007,870 $ 6.58 7.54 $ 2 Vested and expected to vest as of 1,731,437 $ 3.94 7.99 $ 597 Exercisable as of December 31, 2019 1,032,801 $ 4.81 7.20 $ 190 The total intrinsic value of options exercised during the years ended December 31, 2019 and 2018 was $15 and $95 , respectively. As of December 31, 2019 and 2018 , total unrecognized compensation expense related to non-vested stock options was $965 and $1,036 , respectively, which is expected to be recognized over a weighted average period of 0.99 and 1.79 years, respectively. Tangible Stockholder Return Plan Performance Plan On August 2, 2018, the Company’s board of directors approved and established the Tangible Stockholder Return Plan, which is a performance-based long-term incentive plan (the “Performance Plan”). The Performance Plan was effective immediately upon approval and expires on March 1, 2022 . The Performance Plan covers all employees, including the Company’s executive officers, consultants and other persons deemed eligible by the Company’s compensation committee. The core underlying metric of the Performance Plan is the achievement of two share price goals for the Company’s common stock, which if achieved, would represent measurable increases in stockholder value. The Performance Plan is tiered, with two separate tranches, each of which has a distinct share price target (measured as the average publicly traded share price of the Company’s common stock on the Nasdaq stock exchange for a 30 consecutive trading day period) that will, if achieved, trigger a distinct fixed bonus pool. The share price target for the first tranche and related bonus pool are $11.17 per share and $25,000 , respectively. The share price target for the second tranche and related bonus pool are $25.45 per share and $50,000 , respectively. The compensation committee has discretion to distribute the bonus pool related to each tranche among eligible participants by establishing individual minimum bonus amounts before, as well as by distributing the remainder of the applicable pool after, the achievement of each tranche specific share price target. Otherwise, if the Company does not achieve one or both related share price targets, as defined, no portion of the bonus pools will be paid. The Performance Plan provides for the distinct fixed bonus pools to be paid in the form of cash. However, the compensation committee has discretion to pay any bonus due under the Performance Plan in the form of cash, shares of the Company’s common stock or a combination thereof, provided that the Company’s stockholders have approved the reservation of shares of the Company’s common stock for such payment. The Performance Plan permits the compensation committee to make bonus awards subject to varying payment terms, including awards that vest and are payable immediately upon achieving an applicable share price target as well as awards that pay over an extended period (either with or without ongoing employment requirements). The Performance Plan contemplates that no bonus award payments will be delayed beyond 24 months for named executive officers or more than 12 months for all other participants. For purposes of determining whether a share price target has been met, the share price targets will be adjusted in the event of any stock splits, cash dividends, stock dividends, combinations, reorganizations, reclassifications or similar events. In the event of a change in control, as defined in the Performance Plan, during the term of the Performance Plan, a performance bonus pool will become due and payable to participants on a pro rata basis, as calculated and determined by the compensation committee based upon the Company’s progress toward the share price target as of the date of the change in control and subject to adjustment by the compensation committee as permitted under the Performance Plan. The Company has concluded that the Performance Plan is within the scope of ASC 718 , Compensation — Stock Compensation as the underlying plan obligations are based on the potential attainment of certain market share price targets of the Company’s common stock. Any awards under the Performance Plan would be payable, at the discretion of the Company’s compensation committee following the achievement of the applicable share price target, in cash, shares of the Company’s common stock, or a combination thereof, provided that, prior to any payment in common stock, the Company’s stockholders have approved the reservation of shares of the Company’s common stock for such payment. ASC 718 requires that a liability-based award should be classified as a liability on the Company’s consolidated balance sheets and the amount of compensation cost recognized should be based on the fair value of the liability. When a liability-based award includes both a service and market condition, the market condition is taken into account when determining the appropriate method to estimate fair value and the compensation cost is amortized over the estimated service period. Therefore, the liability associated with the Performance Plan obligation is recorded within other long-term liabilities on the Company’s consolidated balance sheets at the estimated fair value on the date of issuance and is re-valued each subsequent reporting period end. The Company recognizes share-based compensation expense within operating expenses in the consolidated statements of operations, including adjustments to the fair value of the liability-based award, on a straight-line basis over the requisite service period. The fair value of obligations under the Performance Plan are estimated using a Monte Carlo simulation approach. The Company’s common stock price is simulated under the Geometric Brownian Motion framework under each simulation path. The other assumptions for the Monte Carlo simulation include the risk-free interest rate, estimated volatility and the expected term. Expected stock price volatility is based on the actual historical volatility of a group of comparable publicly traded companies observed over a historical period equal to the expected remaining life of the plan. The fair value of the underlying common stock is the published closing market price on the Nasdaq Global Market as of each reporting date, as adjusted for significant results, as necessary. The risk-free interest rate is based on the U.S. Treasury yield curve in effect on the date of valuation equal to the remaining expected life of the plan. The dividend yield percentage is zero because the Company does not currently pay dividends, nor does it intend to do so during the expected term of the plan. The expected life of bonus awards under the Performance Plan is assumed to be equivalent to the remaining contractual term based on the estimated service period including the service inception date of the plan participants and the contractual end of the Performance Plan. The fair value of the Performance Plan is estimated at each financial reporting date using the Monte Carlo simulation model and the following assumptions: December 31, 2019 2018 Estimated dividend yield — — Expected volatility 128.30 % 87.19 % Risk-free interest rate 1.53 % 2.47 % Expected term (years) 2.17 3.17 Fair value per share of common stock underlying the Performance Plan $ 0.86 $ 0.83 During the years ended December 31, 2019 and 2018, the Company recorded employee share-based compensation expense related to the Performance Plan of $291

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes There was no income tax benefit recognized for the years ended December 31, 2019 and 2018 due to the Company’s history of net losses combined with an inability to confirm recovery of the tax benefits from the Company’s losses and other net deferred tax assets. The Company has established a valuation allowance against its deferred tax assets due to the uncertainty surrounding the realization of such assets. The reasons for the difference between actual income tax benefit for the years ended December 31, 2019 and 2018 , and the amount computed by applying the statutory federal income tax rate to losses before income tax benefit are as follows: Year Ended December 31, 2019 2018 Income tax benefit at federal statutory rate $ (6,435 ) $ (2,661 ) State income taxes, net of federal benefit (582 ) (570 ) Non-deductible expenses 193 154 Federal rate impact — — Change in fair value of warrants 56 (3,479 ) Research and development tax credits (1,225 ) (1,254 ) Other 330 380 Change in valuation allowance 7,663 7,430 Total income tax provision $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and deferred tax liabilities are as follows: As of December 31, 2019 2018 Deferred tax assets: Accrued compensation $ 13 $ 184 Accrued liabilities 235 149 Tax loss carryforwards 38,042 37,986 Intangible assets 268 286 Share-based compensation 666 814 Tax credits 8,141 6,917 Facility financing lease obligation — 1,847 Research and development service obligation 6,620 — Right-of-use lease liabilities 1,436 — Deferred revenue 572 588 Other 54 10 Total deferred tax assets 56,047 48,781 Less valuation allowance (54,430 ) (46,604 ) Net deferred tax asset 1,617 2,177 Deferred tax liabilities: Fixed assets (1,014 ) (2,032 ) Right-of-use lease assets (421 ) — Other (182 ) (145 ) Net noncurrent deferred tax asset (liability) $ — $ — In December 2017, the Tax Cuts and Jobs Act, or TCJA, was signed into law. Among other things, the TCJA permanently lowers the corporate federal income tax rate to 21% from the existing maximum rate of 35% , effective for tax years including or commencing January 1, 2018. Based on provisions of the TCJA, the Company remeasured its deferred tax assets and liabilities to reflect the lower statutory tax rate, which resulted in a provision of $18,894 to income tax expense. However, there is no impact to the Company’s effective tax rate because a corresponding and offsetting reduction was made in the valuation allowance. The other provisions of the TCJA did not have a material impact on the consolidated financial statements. The Company’s deferred tax remeasurement was complete and all tax effects of the TCJA were reflected in the Company’s income tax provision for the year ended December 31, 2019 . As of December 31, 2019 , the Company had federal and state net operating loss carryforwards of $165,623 and $165,115 , respectively. The net operating loss carryforwards begin to expire in 2028 and 2023 for federal and state tax purposes, respectively. As of December 31, 2019 , the Company had government research and development tax credits of approximately $8,141 to offset future federal taxes which begin to expire in 2028 . The Company had no unrecognized tax benefits as of December 31, 2019 and 2018 . The Company does not anticipate a significant change in total unrecognized tax benefits within the next 12 months. Tax years 2016-2018 remain open to examination by the major taxing jurisdictions to which the Company is subject. Additionally, years prior to 2016 are also open to examination to the extent of loss and credit carryforwards from those years. The Tax Reform Act of 1986 contains provisions which limit the ability to utilize the net operating loss carryforwards in the case of certain events including significant changes in ownership interests. If the Company’s net operating loss carryforwards are limited, and the Company has taxable income which exceeds the permissible yearly net operating loss carryforwards, the Company would incur a federal income tax liability even though net operating loss carryforwards would be available in future years.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Retirement Plan	Retirement Plan The Company maintains a defined contribution savings plan under Section 401(k) of the Internal Revenue Code. This plan covers all employees who meet minimum age requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. The Company has made discretionary matching contributions, up to 3% of gross wages, during 2019 and 2018 . The Company contributed $160 and $208 , for the years ended December 31, 2019 and 2018 , respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Members of the Company’s board of directors held 1,002,776 and 782,083 shares of the Company’s common stock as of December 31, 2019 and 2018 , respectively. Malin Corporation In June 2017, G. Kelly Martin was appointed as the Company’s Interim CEO before being named as the Company’s CEO in April 2018. Mr. Martin continued to serve as a member of the Company’s board of directors following his appointment as Interim CEO and continued to serve as chief executive officer of Malin Corporation plc (“Malin”) until October 1, 2017. Malin is the parent company of Malin Life Sciences Holdings Limited, which beneficially owns approximately 10% of the Company’s outstanding common stock. See Note 16—Subsequent Events regarding the Company’s CEO transition in February 2020. Two of the Company’s directors during 2018 were also affiliated with Malin. Sean Murphy, who resigned from the Company’s board in September 2018, was an executive officer and a director of Malin, and an executive vice president of Malin Corporation plc. In addition, Robert A. Ingram, the Company’s executive chairman of the board, was also a director of Malin Corporation plc until July 2018. Cilatus BioPharma In August 2019, Malin completed the sale of its former subsidiary, Cilatus BioPharma AG (“Cilatus”). Prior to this disposition, Cilatus was majority-owned by Malin. During the nine months ended September 30, 2019 and the year ended and December 31, 2018 , respectively, the Company incurred costs of $250 and $601 in relation to a development and manufacturing consulting agreement with Cilatus. These costs were expensed as incurred and are classified as research and development expenses in the accompanying consolidated statements of operations and comprehensive loss. Health Decisions On October 25, 2018, the Company announced the formation of a dedicated women’s health business unit as well as a foundational collaboration with Health Decisions, Inc. (“Health Decisions”). Health Decisions is a full-service contract research organization specializing in clinical studies of therapeutics for women’s health indications. The Company’s women’s health business unit is led by Paula Brown Stafford, who also is a shareholder and serves on the board of directors of Health Decisions. Reedy Creek Reedy Creek beneficially owns approximately 15% of the Company’s outstanding common stock and approximately 3.9 million warrants, all of which was acquired during the Company’s public offering of common stock and accompanying warrants in January 2018. Accordingly, Reedy Creek is a related party of the Company. The purchase agreement with Reedy Creek, described in Note 6—Research and Development Arrangements, was evaluated and approved pursuant to the Company’s existing related party transactions policy.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Reedy Creek In accordance with the Purchase Agreement with Reedy Creek, Reedy Creek was to provide $10,000 of additional funding contingent upon the Company’s achievement of the primary endpoints in each of the two SB206 clinical trials no later than March 31, 2020. On January 2, 2020, the Company announced top-line results from two pivotal Phase 3 clinical trials of SB206 for the treatment of molluscum contagiosum. SB206 did not achieve statistically significant results in the primary endpoint in both trials, which was the complete clearance of all molluscum lesions at Week 12. Based on such results, the Company understands that Reedy Creek will not be providing the Company with the contingent $10,000 of additional funding. Chief Executive Officer Transition In December 2019 the Company announced that Paula Brown Stafford, the Company’s President and Chief Operating Officer, would succeed G. Kelly Martin as CEO, effective February 2, 2020. Mr. Martin had a fixed term employment contract that expired on February 1, 2020, and completed his service as CEO after fulfilling his term. Mr. Martin also stepped off the Board of Directors, effective February 3, 2020. Ms. Stafford remains a member of the Board of Directors. Board of Directors On January 29, 2020, Dr. Eugene Sun, one of the members of the Company’s board of directors, notified the Company of his resignation from the board and any committees thereof, effective January 29, 2020. Stock Appreciation Rights As described in Note 11—Share-Based Compensation, on August 8, 2018, the Company entered into the Martin Employment Agreement with G. Kelly Martin. The Martin Employment Agreement provided for 1,000,000 SARs and entitled Mr. Martin to a payment (in cash, shares of common stock or a combination of both) equal to the fair market value of one share of the Company’s common stock on the date of exercise less the exercise price of $3.80 per share. The SARs were to be deemed automatically exercised and settled as of February 1, 2020 , provided Mr. Martin remained continuously employed with the Company through such date unless vesting was otherwise expressly accelerated pursuant to the Martin SAR Award. The SARs vested in full on February 1, 2020 . On February 1, 2020, the fair market value of our common stock was $0.52 per share, and as such, the SARs expired unexercised and 1,000,000 shares became available to be granted under the 2016 Plan. Effective December 17, 2019, the Company entered into an amended and restated employment agreement with Paula Brown Stafford, or the Amended and Restated Stafford Employment Agreement. On January 6, 2020, following the release of top-line results of the Company’s Phase 3 molluscum clinical program as provided in the Amended and Restated Stafford Employment Agreement, 600,000 SARs were granted to Ms. Stafford with an exercise price of $0.82 per share (the fair market value of the Company’s common stock on the grant date) and with a ten year term (the “Stafford SAR Award”). The Stafford SAR Award was granted on a contingent basis and would have been considered irrevocably forfeited and voided in full if sufficient shares of the Company’s common stock were not available under the 2016 Plan or if the Company failed to obtain stockholder approval for amendments to the 2016 Plan at the next annual stockholders’ meeting to provide sufficient shares for the Stafford SAR Award. Such shares became available under the 2016 Plan on February 1, 2020, and the SARs were no longer considered granted on a contingent basis. Workforce Reduction As part of a strategic objective to reduce the Company’s costs related to internal resources, facilities, and infrastructure capabilities, the Company took actions in February 2020 that are intended to reduce the Company’s internal resources from a total of 42 employees as of December 31, 2019 to an expected total of 28 employees as of April 1, 2020. Equity Compensation Grant On February 13, 2020, the Company issued 383,000 stock options from the 2016 Plan, (the “Retention Grants”). These Retention Grants were issued to certain employees, vest quarterly and will be fully vested on December 31, 2020, provided that the grantee remains an employee or consultant to the Company as of each vesting date. Women’s Health Business Unit In February 2020, following the successful progression of the Company’s Phase 1 WH602 program, the Company was awarded a Phase 2 federal grant of approximately $1.0 million from the NIH that will enable the conduct of IND-enabling toxicology and pharmacology studies and other preclinical activity with respect to WH602. These funds will be received by the Company in the form of periodic cost reimbursements as the underlying research and development activities are performed. The Company may be eligible to receive an additional $0.5 million in funding as part of this Phase 2 grant, subject to availability of NIH funds and satisfactory progress of the project during the initial 12-month term. Continued Listing Standard On February 19, 2020, the Company received notice from the staff of the Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that, for the last 30 consecutive business days, the market value of the Company’s listed securities has been below the minimum $50.0 million requirement for continued inclusion on The Nasdaq Global Market pursuant to Nasdaq Listing Rule 5450(b)(2)(A). The staff also noted that the Company did not meet alternative requirements for satisfying continued listing criteria found in Nasdaq Listing Rule 5450(b)(3)(A). The Company has 180 calendar days, or until August 16, 2020, to regain compliance with the market value of listed securities requirement. If, at any time before August 16, 2020, the market value of the Company’s listed securities closes at $50.0 million or more for a minimum of 10 consecutive business days, Nasdaq will provide written notification to the Company that it complies with the market value of listed securities requirement. On February 19, 2020, the Company also received notice from the staff of Nasdaq notifying the Company that, for the last 30 consecutive business days, the minimum bid price of the Company’s common stock has not exceeded $1.00 per share and that the Company was therefore not in compliance with the minimum bid price requirement under Nasdaq Listing Rule 5450(a)(1). The Company has 180 calendar days, or until August 16, 2020, to regain compliance with the minimum bid price requirement. To regain compliance, the closing bid price of the common stock must meet or exceed $1.00 per share for a minimum of 10 consecutive business days prior to August 16, 2020. The Company intends to continue to monitor the bid price levels for the common stock, and will consider appropriate alternatives to achieve compliance within the 180-day compliance period (or such subsequent date if the compliance period is extended).

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	The accompanying consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). Additionally, each of the two reports of the Company’s independent registered public accounting firm on the Company’s consolidated financial statements as of and for the years ended December 31, 2019 and December 31, 2018 , respectively, included an explanatory paragraph indicating that there is substantial doubt about the Company’s ability to continue as a going concern.
Basis of Consolidation	Basis of Consolidation The accompanying consolidated financial statements reflect the operations of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Liquidity and Ability to Continue as a Going Concern	Liquidity and Ability to Continue as a Going Concern The Company’s consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The accompanying consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from uncertainty related to the Company’s ability to continue as a going concern. The Company has evaluated principal conditions and events that may raise substantial doubt about its ability to continue as a going concern within one year from the date that these financial statements are issued. The Company identified the following conditions: • The Company has reported a net loss in all fiscal periods since inception and, as of December 31, 2019 , the Company had an accumulated deficit of $203,682 . • As described in Note 9—Stockholders’ Equity, in August 2019 the Company entered into a common stock purchase agreement (the “Aspire Common Stock Purchase Agreement”) with Aspire Capital Fund, LLC, (“Aspire Capital”) which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $25,000 of shares of the Company’s common stock at the Company’s request from time to time during the 30 -month term of the Aspire Common Stock Purchase Agreement. The aggregate amount available to the Company through sales of common stock under the Aspire Common Stock Purchase Agreement is subject to certain limitations including, but not limited to: (i) the number of shares that may be sold will be limited to 5,211,339 shares, representing 19.99% of the Company’s outstanding shares of common stock on August 30, 2019, if the average price paid for all shares issued under the agreement is less than $2.17 ; and (ii) on any purchase date, the closing sale price of the Company’s common stock must be greater than or equal to $0.25 . As of December 31, 2019, the Company had sold 300,000 shares of common stock at an average price of $2.49 per share under the Aspire Common Stock Purchase Agreement. As of January 31, 2020, the Company had sold an aggregate of 1,000,000 shares of common stock at an average price of $1.19 per share under the Aspire Common Stock Purchase Agreement. These amounts, combined with the 345,622 shares issued as part of the commitment fee related to the agreement’s execution, leads to a total of 1,345,622 shares issued to Aspire Capital under the Aspire Common Stock Purchase Agreement as of January 31, 2020. • As of December 31, 2019 , the Company had a total cash and cash equivalents balance of $13,711 . The Company has concluded that the prevailing conditions and ongoing liquidity risks faced by the Company raise substantial doubt about its ability to continue as a going concern. Based on its current cash flow forecast, the Company does not currently have sufficient cash and cash equivalents to continue its business operations beyond the early part of the second quarter of 2020 . Therefore, the Company will need to raise substantial additional funding by the early part of the second quarter of 2020 in order to continue its operating activities and make further advancements in its drug development programs. There can be no assurance that the Company will be able to obtain additional capital on terms acceptable to the Company, on a timely basis or at all. The failure of the Company to obtain sufficient funds on acceptable terms could have a material adverse effect on the Company’s business and cause the Company to alter or reduce its planned operating activities, including but not limited to delaying, reducing, terminating or eliminating planned product candidate development activities, to conserve its cash and cash equivalents. The Company needs and intends to secure additional capital from non-dilutive sources, including partnerships, collaborations, licensing, grants or other strategic relationships, or through equity or debt financings. Any issuance of equity or debt that could be convertible into equity would result in significant dilution to our existing stockholders. Alternatively, the Company may seek to engage in one or more potential transactions, such as the sale of the Company, or sale or divestiture of some of its assets, such as a sale of its dermatology platform assets, but there can be no assurance that the Company will be able to enter into such a transaction or transactions on a timely basis or at all on terms that are favorable to the Company. Under these circumstances, the Company may instead determine to dissolve and liquidate its assets or seek protection under the bankruptcy laws. If the Company decides to dissolve and liquidate its assets or to seek protection under the bankruptcy laws, it is unclear to what extent the Company will be able to pay its obligations, and, accordingly, it is further unclear whether and to what extent any resources will be available for distributions to stockholders.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from these estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid instruments purchased with a maturity of three months or less to be cash equivalents. Cash and cash equivalents include deposits and money market accounts.
Restricted Cash	Restricted Cash Restricted cash as of December 31, 2019 and 2018 includes funds maintained in a separate deposit account to secure a letter of credit for the benefit of the lessor of facility space leased by the Company.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of cash and cash equivalents. The Company places its cash and cash equivalents with financial institutions and these deposits may at times be in excess of insured limits.
Contracts and Grants Receivable	Contracts and Grants Receivable The Company carries its contracts and grants receivable net of an allowance for doubtful accounts. All receivables or portions thereof that are deemed to be uncollectible or that require excessive collection costs are written off to the allowance for doubtful accounts when it is probable that the receivable is unrecoverable. The Company actively reviews and evaluates its contracts and grants receivable, but no allowance for doubtful accounts has been considered necessary as of December 31, 2019 . Actual results could differ from the estimates that were used.
Intangible Assets	Intangible Assets Intangible assets represent the cost to obtain and register the Company’s internet domain. Indefinite-lived intangible assets are not amortized and are assessed for impairment at least annually.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives as follows: Computer and office equipment 3 years Furniture and fixtures 5-7 years Laboratory equipment 7 years Building asset under facility lease 25 years Leasehold improvements are amortized over the shorter of the life of the lease or the useful life of the improvements. Expenditures for maintenance and repairs are expensed as incurred. Improvements and betterments that add new functionality or extend the useful life of an asset are capitalized.
Intellectual Property	Intellectual Property The Company’s policy is to file patent applications to protect technology, inventions and improvements that are considered important to its business. Patent positions, including those of the Company, are uncertain and involve complex legal and factual questions for which important legal principles are largely unresolved. Due to the uncertainty of future value to be realized from the expenses incurred in developing the Company’s intellectual property, the cost of filing, prosecuting and maintaining internally developed patents are expensed as general and administrative costs as incurred.
Leases	Leases The Company leases office space and certain equipment under non-cancelable lease agreements. Prior to January 1, 2019, the Company applied the accounting guidance in ASC 840, Leases , to its lease agreements. The leases were reviewed for classification as operating or capital leases. For operating leases, rent was recognized on a straight-line basis over the lease period. For capital leases, the Company recorded the leased asset with a corresponding liability and amortized the asset over the lease term. Payments were recorded as reductions to the liability with an appropriate interest charge recorded based on the then-outstanding remaining liability. Beginning January 1, 2019, the Company applies the accounting guidance in ASC 842, Leases. As such, the Company assesses all arrangements, that convey the right to control the use of property, plant and equipment, at inception, to determine if it is, or contains, a lease based on the unique facts and circumstances present in that arrangement. For those leases identified, the Company determines the lease classification, recognition, and measurement at the lease commencement date. For arrangements that contain a lease the Company: (i) identifies lease and non-lease components; (ii) determines the consideration in the contract; (iii) determines whether the lease is an operating or financing lease; and (iv) recognizes lease Right of Use (“ROU”) assets and corresponding lease liabilities. Lease liabilities are recorded based on the present value of lease payments over the expected lease term. The corresponding ROU asset is measured from the initial lease liability, adjusted by (i) accrued or prepaid rents; (ii) remaining unamortized initial direct costs and lease incentives; and (iii) any impairments of the ROU asset. The interest rate implicit in the Company’s lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. Prior to January 1, 2019, the Company applied the accounting guidance in ASC 840, Leases , to its lease agreements. The leases were reviewed for classification as operating or capital leases. For operating leases, rent was recognized on a straight-line basis over the lease period. For capital leases, the Company recorded the leased asset with a corresponding liability and amortized the asset over the lease term. Payments were recorded as reductions to the liability with an appropriate interest charge recorded based on the then-outstanding remaining liability. The Company considered the nature of the renovations and the Company’s involvement during the construction period of previously leased office space to determine if it was considered to be the owner of the construction project during the construction period. If the Company determined that it was the owner of the construction project, it was required to capitalize the fair value of the building as well as the construction costs incurred, including capitalized interest, on its consolidated balance sheet along with a corresponding financing liability (“build-to-suit accounting”). Upon completion of the construction of the facility under a build-to-suit lease, the Company assessed whether the circumstances qualified for sales recognition under the sale-leaseback accounting guidance. If the lease met the sale-leaseback criteria, the Company would remove the asset and related financial obligation from the balance sheet and evaluate the lease for treatment as a capital or operating lease. If upon completion of construction, the project did not meet the sale-leaseback criteria, the leased property was treated as an asset financing for financial reporting purposes. The portion of the facility financing obligation representing the principal that was to be repaid in the following 12 months was classified as a current liability in the consolidated balance sheets, with the remaining portion of the obligation classified as a noncurrent liability. Beginning January 1, 2019, the Company applies the accounting guidance in ASC 842, Leases. As such, the Company assesses all arrangements, that convey the right to control the use of property, plant and equipment, at inception, to determine if it is, or contains, a lease based on the unique facts and circumstances present in that arrangement. For those leases identified, the Company determines the lease classification, recognition, and measurement at the lease commencement date. For arrangements that contain a lease the Company: (i) identifies lease and non-lease components; (ii) determines the consideration in the contract; (iii) determines whether the lease is an operating or financing lease; and (iv) recognizes lease ROU assets and corresponding lease liabilities. Lease liabilities are recorded based on the present value of lease payments over the expected lease term. The corresponding ROU asset is measured from the initial lease liability, adjusted by (i) accrued or prepaid rents; (ii) remaining unamortized initial direct costs and lease incentives; and (iii) any impairments of the ROU asset. The interest rate implicit in the Company’s lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. The Company has elected to separate lease components (fixed rent payments) with non-lease components (common-area maintenance costs) on its real estate assets. Fixed lease payments on operating leases are recognized over the expected term of the lease on a straight-line basis. Variable lease expenses that are not considered fixed are expensed as incurred. Fixed and variable lease expense on operating leases is recognized within operating expenses within our consolidated statements of operations. The Company has elected the short-term lease exemption and, therefore, does not recognize a ROU asset or corresponding liability for lease arrangements with an original term of 12 months or less. The Company has elected to separate lease components (fixed rent payments) with non-lease components (common-area maintenance costs) on its real estate assets. Fixed lease payments on operating leases are recognized over the expected term of the lease on a straight-line basis. Variable lease expenses that are not considered fixed are expensed as incurred. Fixed and variable lease expense on operating leases is recognized within operating expenses within our consolidated statements of operations. The Company has elected the short-term lease exemption and, therefore, does not recognize a ROU asset or corresponding liability for lease arrangements with an original term of 12 months or less. The Company adopted Topic 842 as of January 1, 2019 using the modified retrospective transition method and initially applied the transition provisions as of January 1, 2019. This transition method allowed the Company to continue to apply the legacy guidance in ASC 840 for periods prior to 2019 and recognize a cumulative-effect adjustment to the opening balance of accumulated deficit as of the date of adoption. The Company elected the package of transition practical expedients, which, among other things, allowed the Company to keep the historical lease classifications and not have to reassess the lease classification for any existing leases as of the date of adoption. The Company also made an accounting policy election to apply the short-term lease exception, which allows the Company to exclude leases with an initial term of twelve months or less from the consolidated balance sheets.
Impairment of Long-lived Assets	Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized for an amount by which the carrying amount of the asset exceeds the fair value of the asset.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs consist of legal, accounting, filing and other fees directly related to offerings or the Company’s shelf registration. These costs are offset against proceeds from each offering as applicable. Offering costs incurred prior to the completion of an offering are initially capitalized as assets, evaluated each period for likelihood of completion and subsequently reclassified to additional paid-in capital upon completion of the offering. Deferred costs associated with the shelf registration will be reclassified to additional paid in capital on a pro-rata basis in the event the Company completes an offering under the shelf registration, with any remaining deferred offering costs charged to general and administrative expense at the end of the three -year life of the shelf registration.
Revenue Recognition	Revenue Recognition Effective January 1, 2018, the Company adopted ASC Topic 606, Revenue from Contracts with Customers , using the full retrospective transition method. To determine revenue recognition for arrangements that the Company determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contracts with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Upon occurrence of a contract modification, the Company conducts an evaluation pursuant to the modification framework in Topic 606 to determine the appropriate revenue recognition. The framework centers around key questions, including (i) whether the modification adds additional goods and services, (ii) whether those goods and services are distinct, and (iii) whether the contract price increases by an amount that reflects the standalone selling price for the new goods or services. The resulting conclusions will determine whether the modification is treated as a separate, standalone contract or if it is combined with the original contract and accounted for in that manner. In addition, some modifications are accounted for on a prospective basis and others on a cumulative catch-up basis. The Company’s agreements may contain some or all the following types of provisions or payments: Licenses of Intellectual Property : If the license of the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the estimated performance period and the appropriate method of measuring progress during the performance period for purposes of recognizing revenue. The Company re-evaluates the estimated performance period and measure of progress each reporting period and, if necessary, adjusts related revenue recognition accordingly. Milestone Payments : At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license and collaboration revenue and earnings in the period of adjustment. Manufacturing Supply Services : Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to the licensee and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded in license and collaboration revenue when the customer obtains control of the goods, which is upon delivery. Royalties : For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. The Company’s revenue also includes research revenue earned under contracts and grants with Federal government agencies, which relates to the research and development of its nitric oxide platform. Government research contracts and grants revenue . Under the terms of the contracts and grants awarded, the Company is entitled to receive reimbursement of its allowable direct expenses, allocated overhead, general and administrative expenses and payment of other specified amounts. Revenues from development and support activities under government research contracts and grants are recorded in the period in which the related costs are incurred. Associated expenses are recognized when incurred as research and development expense. Revenue recognized in excess of amounts collected from funding sources are recorded as contracts and grants receivable. Any of the funding sources may, at their discretion, request reimbursement for expenses or return of funds, or both, as a result of noncompliance by the Company with the terms of the grants. No reimbursement of expenses or return of funds has been requested or made since inception of the contracts and grants. See Note 5—Revenue Recognition for information regarding two government grants the Company received in the third quarter of 2019.
Research and Development Expenses	Research and Development Expenses Research and development expenses include all direct and indirect development costs incurred for the development of the Company’s drug candidates. These expenses include salaries and related costs, including share-based compensation and travel costs for research and development personnel, allocated facility costs, laboratory and manufacturing materials and supplies, consulting fees, product development, preclinical studies, clinical trial costs, licensing fees and milestone payments under license agreements and other fees and costs related to the development of drug candidates. The cost of tangible and intangible assets that are acquired for use on a particular research and development project, have no alternative future uses, and are not required to be capitalized in accordance with the Company’s capitalization policy, are expensed as research and development costs as incurred.
Accrued Outside Research and Development Expense Accruals	Accrued Outside Research and Development Accruals The Company is required to estimate its expenses resulting from its obligations under contracts with clinical research organizations, clinical site agreements, vendors, and consultants in connection with conducting clinical trials and preclinical development. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company’s objective is to reflect the appropriate development and clinical trial expenses in its financial statements by matching those expenses with the period in which the services and efforts are expended. For clinical trials, the Company accounts for these expenses according to the progress of the trial as measured by actual hours expended by contract research organization personnel, investigator performance or completion of specific tasks, patient progression, or timing of various aspects of the trial. During the course of a clinical trial, the Company adjusts its rate of clinical trial expense recognition if actual results differ from its estimates. The Company utilizes judgment and experience to estimate its accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known at that time. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of status and timing of services performed relative to the actual status and timing of services performed may vary and may result in increases or decreases in research and development expenses in future periods when the actual results become known. For preclinical development services performed by outside service providers, the Company determines accrual estimates through financial models, considering development progress data received from outside service providers and discussions with applicable Company and service provider personnel.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying values of cash equivalents, accounts payable and accrued liabilities as of December 31, 2019 and 2018 approximated their fair values due to the short-term nature of these items. For warrants that are issued or modified and there is a deemed possibility that the Company may have to settle them in cash, it records the fair value of the warrants at the initial measurement date, or date of issuance, and each balance sheet date thereafter. Changes in the estimated fair value of the warrants are recognized as a non-cash gain or loss on the consolidated statements of operations and comprehensive loss. The Company has categorized its financial instruments, based on the priority of the inputs used to value the investments, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and lowest priority to unobservable inputs (Level 3). If the inputs used to measure the investments fall within different levels of the hierarchy, the categorization is based on the lowest level input that is significant to the fair value measurement of the investment. Financial instruments recorded in the accompanying consolidated balance sheets are categorized based on the inputs to valuation techniques as follows: Level 1 - Observable inputs that reflect unadjusted quoted market prices for identical assets or liabilities in active markets. Level 2 - Observable inputs other than Level 1 that are observable, either directly or indirectly, in the marketplace for identical or similar assets and liabilities. Level 3 - Unobservable inputs that are supported by little or no market data, where values are derived from techniques in which one or more significant inputs are unobservable. Due to the Company’s limited historical stock price data, the Company estimates stock price volatility based on the actual historical volatility of a group of comparable publicly traded companies observed over a historical period equal to the expected life of the warrant. The fair value of the common stock warrants is estimated using a valuation model that approximates a Monte Carlo simulation model, which takes into consideration the probability of a fundamental transaction occurring during the contractual term of the warrants.
Share-Based Compensation	Share-Based Compensation Equity-Based Awards The Company applies the fair value method of accounting for share-based compensation, which requires all such compensation to employees, including the grant of employee stock options, to be recognized in the consolidated statements of operations and comprehensive loss based on its fair value at the measurement date (generally the grant date). The expense associated with share-based compensation is recognized over the requisite service period of each award. For awards with only service conditions and graded-vesting features, the Company recognizes compensation cost on a straight-line basis over the requisite service period. For awards with performance conditions, once achievement of the performance condition becomes probable, compensation cost is recognized over the expected period from the date the performance condition becomes probable to the date the performance condition is expected to be achieved. The Company will reassess the probability of vesting at each reporting period for performance awards and adjust compensation cost based on its probability assessment. Share-based awards granted to non-employee directors as compensation for serving on the Company’s board of directors are accounted for in the same manner as employee share-based compensation awards. The fair value of each option grant is estimated using a Black-Scholes option-pricing model on the grant date using expected volatility, risk-free interest rate, expected life of options and fair value per share assumptions. Due to limited historical data, the Company estimates stock price volatility based on the actual volatility of comparable publicly traded companies over the expected life of the option. In evaluating similarity, the Company considered factors such as industry, stage of life cycle, financial leverage, size and risk profile. The Company does not have sufficient stock option exercise history to estimate the expected term of employee stock options and thus continues to calculate expected life based on the mid-point between the vesting date and the contractual term, which is in accordance with the simplified method. The expected term for share-based compensation granted to non-employees is the contractual life. The risk-free rate is based on the U.S. Treasury yield curve during the expected life of the option. The Company estimates forfeitures based on the historical experience of the Company and adjusts the estimated forfeiture rate based upon actual experience. Liability-Based Awards Stock appreciation rights (“SARs”) that include cash settlement features are accounted for as liability-based awards pursuant to ASC 718 Share Based Payments . The fair value of such SARs is estimated using a Black-Scholes option-pricing model on each financial reporting date using expected volatility, risk-free interest rate, expected life and fair value per share assumptions. The fair value of obligations under the Tangible Stockholder Return Plan are estimated using a Monte Carlo simulation approach. The Company’s common stock price is simulated under the Geometric Brownian Motion framework under each simulation path. The other assumptions for the Monte Carlo simulation include the risk-free interest rate, estimated volatility and the expected term. The fair value of each liability award is estimated with a valuation model that uses certain assumptions, such as the award date, expected volatility, risk-free interest rate, expected life of the award and fair value per share assumptions. Due to limited historical data, the Company estimates stock price volatility based on the actual volatility of comparable publicly traded companies over the expected term. In evaluating similarity, the Company considered factors such as industry, stage of life cycle, financial leverage, size and risk profile. The expected term for liability-based awards is the estimated contractual life. The risk-free rate is based on the U.S. Treasury yield curve during the expected life of the award. Due to the contingent nature of the SAR grant, prior to stockholder approval on July 31, 2019, these share-based payment awards were classified as liabilities and the amount of compensation cost recognized was based on the fair value of those liabilities. The corresponding obligation was recorded within other long-term liabilities on the Company’s consolidated balance sheet at the estimated fair value on the date of issuance and was re-valued each subsequent reporting period with adjustments to the fair value recognized as share-based compensation expense in the consolidated statements of operations. ASC 718 requires that a liability-based award should be classified as a liability on the Company’s consolidated balance sheets and the amount of compensation cost recognized should be based on the fair value of the liability. When a liability-based award includes both a service and market condition, the market condition is taken into account when determining the appropriate method to estimate fair value and the compensation cost is amortized over the estimated service period. Therefore, the liability associated with the Performance Plan obligation is recorded within other long-term liabilities on the Company’s consolidated balance sheets at the estimated fair value on the date of issuance and is re-valued each subsequent reporting period end. The Company recognizes share-based compensation expense within operating expenses in the consolidated statements of operations, including adjustments to the fair value of the liability-based award, on a straight-line basis over the requisite service period. The fair value of obligations under the Performance Plan are estimated using a Monte Carlo simulation approach. The Company’s common stock price is simulated under the Geometric Brownian Motion framework under each simulation path. The other assumptions for the Monte Carlo simulation include the risk-free interest rate, estimated volatility and the expected term. Expected stock price volatility is based on the actual historical volatility of a group of comparable publicly traded companies observed over a historical period equal to the expected remaining life of the plan. The fair value of the underlying common stock is the published closing market price on the Nasdaq Global Market as of each reporting date, as adjusted for significant results, as necessary. The risk-free interest rate is based on the U.S. Treasury yield curve in effect on the date of valuation equal to the remaining expected life of the plan. The dividend yield percentage is zero because the Company does not currently pay dividends, nor does it intend to do so during the expected term of the plan. The expected life of bonus awards under the Performance Plan is assumed to be equivalent to the remaining contractual term based on the estimated service period including the service inception date of the plan participants and the contractual end of the Performance Plan.
Income Taxes	Income Taxes Deferred tax assets and liabilities are determined based on the temporary differences between the financial statement carrying amounts and the tax bases of assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. In estimating future tax consequences, all expected future events are considered other than enactment of changes in the tax law or rates. The Company did not record a federal or state income tax benefit for the years ended December 31, 2019 and 2018 due to its conclusion that a full valuation allowance is required against the Company’s deferred tax assets. The determination of recording or releasing a tax valuation allowance is made, in part, pursuant to an assessment performed by management regarding the likelihood that the Company will generate future taxable income against which benefits of its deferred tax assets may or may not be realized. This assessment requires management to exercise judgment and make estimates with respect to its ability to generate taxable income in future periods. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The Company’s policy for recording interest and penalties is to record them as a component of general and administrative expenses. As of December 31, 2019 and 2018 , the Company accrued no interest and penalties related to uncertain tax positions. Tax years 2016-2018 remain open to examination by the major taxing jurisdictions to which the Company is subject. Additionally, years prior to 2016 are also open to examination to the extent of loss and credit carryforwards from those years. In accordance with Section 382 of the Internal Revenue Code of 1986, as amended, a change in equity ownership of greater than 50% within a three-year period results in an annual limitation on the Company’s ability to utilize its net operating loss carryforwards created during the tax periods prior to the change in ownership. The Company has not determined whether ownership changes exceeding this threshold, including the Company’s IPO and the January 2018 Offering, have occurred. If a change in equity ownership has occurred which exceeds the Section 382 threshold, a portion of the Company’s net operating loss carryforwards may be limited.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are anti-dilutive for all periods presented.
Segment and Geographic Information	Segment and Geographic Information The Company has determined that it operates in one segment. The Company uses its nitric oxide-based technology to develop product candidates. The Chief Executive Officer (“CEO”), who is the Company’s chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has only had limited revenue since its inception, but substantially all revenue was derived from licensing agreements originating in the United States. All of the Company’s long-lived assets are maintained in the United States.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Accounting Pronouncements Adopted In February 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) . This guidance revises the accounting related to leases by requiring lessees to recognize a lease liability and a right-of-use asset for all leases. The new lease guidance also simplifies the accounting for sale and leaseback transactions. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements, and in March 2019, the FASB issued ASU 2019-01, Leases (Topic 842): Codification Improvements. These additional ASUs were issued to provide expanded or clarifying guidance associated with the application of certain principles . Under the guidance, lessees are required to recognize assets and lease liabilities on the balance sheet for most leases including operating leases and provide enhanced disclosures. There are optional practical expedients that a company may elect to apply. The guidance was effective for the Company beginning in its first quarter of 2019. The Company adopted Topic 842 as of January 1, 2019 using the modified alternative retrospective transition method and initially applied the transition provisions as of January 1, 2019. This transition method allowed the Company to continue to apply the legacy guidance in ASC 840 for periods prior to 2019 and recognize a cumulative-effect adjustment to the opening balance of accumulated deficit as of the date of adoption. The Company elected the package of transition practical expedients, which, among other things, allowed the Company to keep the historical lease classifications and not have to reassess the lease classification and initial direct costs for any existing or expired leases as of the date of adoption. The Company also made an accounting policy election to apply the short-term lease exception, which allows the Company to exclude leases with an initial term of twelve months or less from the consolidated balance sheets. Lease expense for leases with an initial term of twelve months or less will be recognized over the lease term, similar to the accounting treatment under ASC 840. As a result of the adoption of Topic 842, the Company derecognized $10,557 of building assets (property, plant and equipment), and the $7,998 facility financing obligation associated with the previously existing build-to-suit arrangement related to its sole corporate and manufacturing facility. The Company also capitalized leasehold improvements and ROU assets of $5,885 and $1,827 , respectively, and recorded lease liabilities for operating leases totaling $6,786 , as of January 1, 2019. The capitalized leasehold improvement assets recorded as part of the adoption of Topic 842 were previously included within the derecognized building asset as part of the previous build-to-suit arrangement. The Company also recognized an increase of $714 to accumulated deficit related to its de-recognition of its previously recorded build-to-suit arrangement. The impact of the adoption of this guidance is non-cash in nature and did not affect the Company’s cash flows. See Note 8—Commitments and Contingencies for additional information related to the adoption of Topic 842. In June 2018 the FASB issued ASU 2018-08 Not-for-Profit Entities (Topic 958): Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made. This guidance clarifies and improves the scope and the accounting guidance for contributions received and contributions made, in order to reduce diversity in practice for grants and other similar contracts. For contributions (nonreciprocal transactions), an entity should follow the guidance in ASC 958-605 Not-for-Profit Entities - Revenue Recognition, and for exchange (reciprocal) transactions an entity should follow other guidance. This standard is effective for annual reporting periods beginning after June 15, 2018, including interim reporting periods within those annual reporting periods, with early adoption permitted. This ASU was effective for the Company as of January 1, 2019. The adoption of this new accounting guidance did not have a material impact on the Company’s consolidated financial statements. See Note 5—Revenue Recognition for information related to the adoption of Topic 958. In June 2018, the FASB issued ASU No. 2018-07 Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting . This guidance simplifies the accounting for non-employee share-based payment transactions by expanding the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. Under the new standard, most of the guidance on stock compensation payments to non-employees would be aligned with the requirements for share-based payments granted to employees. This standard is effective for annual reporting periods beginning after December 15, 2018, including interim reporting periods within those annual reporting periods, with early adoption permitted. This ASU was effective for the Company as of January 1, 2019. The adoption of this new accounting guidance did not have a material impact on the Company’s consolidated financial statements. Accounting Pronouncements Being Evaluated In August 2018, the FASB issued ASU No. 2018-13 Fair Value Measurement (Topic 820): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement. This guidance is intended to improve the effectiveness of disclosure requirements on fair value measurements in Topic 820. The new standard modifies certain disclosure requirements and will be effective for annual reporting periods beginning after December 15, 2019. The new guidance is not expected to have a material impact on the Company’s consolidated financial statements. In October 2018, the FASB issued ASU No. 2018-17 Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities. This guidance is intended to improve the accounting for variable interest entities and whether the entity should be consolidated. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim reporting periods within those annual reporting periods, with early adoption permitted. The new guidance is not expected to have a material impact on the Company’s consolidated financial statements. In November 2018, the FASB issued ASU No. 2018-18 Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 . This guidance is intended to reduce diversity in practice and clarify the interaction between Topic 808, Collaborative Arrangements , and Topic 606, Revenue from Contracts with Customers . This ASU provided guidance on whether certain transactions between collaborative arrangement participants should be accounted for with revenue under Topic 606. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim reporting periods within those annual reporting periods, with early adoption permitted. The new guidance is not expected to have a material impact on the Company’s consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12 Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This guidance is intended to improve consistent application and simplify the accounting for income taxes. This ASU removes certain exceptions to the general principles in Topic 740 and clarifies and amends existing guidance. This standard is effective for annual reporting periods beginning after December 15, 2020, including interim reporting periods within those annual reporting periods, with early adoption permitted. The Company is currently evaluating the impact of adoption of this ASU and does not expect the adoption of this new standard to have a material impact on its consolidated financial statements.

Organization and Significant _3

Organization and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Property and Equipment	Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives as follows: Computer and office equipment 3 years Furniture and fixtures 5-7 years Laboratory equipment 7 years Building asset under facility lease 25 years Property and equipment consisted of the following: December 31, 2019 2018 Computer equipment $ 575 $ 577 Furniture and fixtures 305 312 Laboratory equipment 7,898 7,442 Office equipment 339 400 Building related to facility lease obligation — 10,557 Leasehold improvements 7,068 1,168 Property and equipment, gross 16,185 20,456 Less: Accumulated depreciation and amortization (5,679 ) (4,588 ) Total property and equipment, net $ 10,506 $ 15,868
Summary of Anti-dilutive Securities Excluded from Calculation of Weighted Average Common Shares Outstanding	The following securities, presented on a common stock equivalent basis, have been excluded from the calculation of weighted average common shares outstanding for the years ended December 31, 2019 and 2018 because the effect is anti-dilutive due to the net loss reported in each of those periods. All share amounts presented in the table below represent the total number outstanding as of the end of each period. December 31, 2019 2018 Warrants to purchase common stock associated with January 2018 public offering (Note 10) 10,000,000 10,000,000 Stock options outstanding under the 2008 and 2016 Plans (Note 11) 1,663,803 1,671,666 Stock appreciation rights outstanding under the 2016 Plan (Note 11) 1,000,000 — Inducement options outstanding (Note 11) 125,500 100,500

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Contract Assets and Contract Liabilities	The following table presents the Company’s contract assets and contract liabilities balances for the periods indicated. Contract Asset Contract Liability Net Deferred Revenue December 31, 2018 $ 17,790 $ 24,757 $ 6,967 December 31, 2019 $ 8,974 $ 20,478 $ 11,504 Short-term Deferred Revenue Long-term Deferred Revenue Net Deferred Revenue December 31, 2018 $ 4,401 $ 2,566 $ 6,967 December 31, 2019 $ 4,428 $ 7,076 $ 11,504

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives as follows: Computer and office equipment 3 years Furniture and fixtures 5-7 years Laboratory equipment 7 years Building asset under facility lease 25 years Property and equipment consisted of the following: December 31, 2019 2018 Computer equipment $ 575 $ 577 Furniture and fixtures 305 312 Laboratory equipment 7,898 7,442 Office equipment 339 400 Building related to facility lease obligation — 10,557 Leasehold improvements 7,068 1,168 Property and equipment, gross 16,185 20,456 Less: Accumulated depreciation and amortization (5,679 ) (4,588 ) Total property and equipment, net $ 10,506 $ 15,868

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	At December 31, 2019 , maturities of operating lease liabilities over each of the next five years and thereafter are as follows: Operating Leases 2020 $ 1,215 2021 1,241 2022 1,278 2023 1,317 2024 1,356 Thereafter 2,111 Total minimum lease payments $ 8,518 Less imputed interest $ (2,256 ) Total lease liability $ 6,262

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Reserved Shares of Common Stock for Future Issuance	The Company had reserved shares of common stock for future issuance as follows: December 31, 2019 2018 Outstanding stock options (Note 11) 1,789,303 1,671,666 Warrants to purchase common stock issued in January 2018 Offering 10,000,000 10,000,000 Outstanding stock appreciation rights (Note 11) 1,000,000 — For possible future issuance under 2016 Stock Plan (Note 11) 388,463 699,376 13,177,766 12,371,042

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2019
Warrants and Rights Note Disclosure [Abstract]
Summary of Warrant Liability Measured at Fair Value on a Recurring Basis	The following table presents the Company’s warrant liability measured at fair value on a recurring basis as of December 31, 2019 and 2018: December 31, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Liabilities: Warrant liability $ — $ — $ 1,504 $ 1,504 Total liabilities at fair value $ — $ — $ 1,504 $ 1,504 December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Liabilities: Warrant liability $ — $ — $ 1,240 $ 1,240 Total liabilities at fair value $ — $ — $ 1,240 $ 1,240
Summary of Fair Value Assumptions for Common Stock Warrants	The inputs to the valuation model that approximates a Monte Carlo simulation model are presented below. December 31, 2019 2018 Estimated dividend yield — — Expected volatility 100% - 101.73% 77.74%-100% Risk-free interest rate 1.58 % 2.46 % Expected term (years) 2.03 3.02 Fair value per share of common stock underlying the warrant $ 0.86 $ 0.83 Warrant exercise price $ 4.66 $ 4.66
Summary of Change in Fair Value of Warrant Liability, Valued Using Significant Unobservable Level 3 Inputs	The following table summarizes the change in the fair value of the warrant liability, which is valued using significant unobservable Level 3 inputs, for the years ended December 31, 2019 and 2018: December 31, 2019 2018 Beginning Balance $ 1,240 $ — Issuance $ — $ 17,806 Revaluations Included In Earnings $ 264 $ (16,566 ) Exercises $ — $ — Expirations $ — $ — Ending Balance $ 1,504 $ 1,240

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of fair value assumptions	The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, and the following weighted average assumptions: Year Ended December 31, 2019 2018 Estimated dividend yield 0.00 % 0.00 % Expected volatility 102.14 % 81.73 % Risk-free interest rate 1.87 % 2.75 % Expected life of options (in years) 5.20 5.68 Weighted-average fair value per share $ 1.77 $ 2.06 The fair value of the SARs was estimated using the Black-Scholes option-pricing model for the respective periods, using the following assumptions: July 31, 2019 December 31, 2018 Estimated dividend yield — — Expected volatility 115.82 % 86.71 % Risk-free interest rate 2.07 % 2.63 % Expected term (years) 0.51 1.09 Fair value per share of common stock underlying the SAR $ 2.66 $ 0.83 SAR exercise price $ 3.80 $ 3.80 The fair value of the Performance Plan is estimated at each financial reporting date using the Monte Carlo simulation model and the following assumptions: December 31, 2019 2018 Estimated dividend yield — — Expected volatility 128.30 % 87.19 % Risk-free interest rate 1.53 % 2.47 % Expected term (years) 2.17 3.17 Fair value per share of common stock underlying the Performance Plan $ 0.86 $ 0.83
Schedule of Share-based Compensation Expenses	Total share-based compensation expense included in the consolidated statements of operations is as follows: Year Ended December 31, 2019 2018 Research and development $ 710 $ 1,144 General and administrative 1,128 1,060 $ 1,838 $ 2,204
Summary of Stock Option Activity	Stock option activity for the periods indicated is as follows: Shares Available for Grant Shares Subject to Outstanding Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Options outstanding as of December 31, 2017 1,023,378 1,399,484 $ 7.17 Additional shares reserved under plan — — Options granted (626,757 ) 727,257 2.97 Options forfeited 302,755 (403,748 ) 7.61 Options exercised — (51,327 ) 1.16 Options outstanding as of December 31, 2018 699,376 1,671,666 $ 5.42 Options granted (633,030 ) 658,030 2.36 Options forfeited 322,117 (507,950 ) 7.07 Options exercised — (32,443 ) 2.12 Options outstanding as of December 31, 2019 388,463 1,789,303 $ 3.89 8.03 $ 638 Vested and expected to vest as of 1,585,689 $ 5.53 8.11 $ 2 Exercisable as of December 31, 2018 1,007,870 $ 6.58 7.54 $ 2 Vested and expected to vest as of 1,731,437 $ 3.94 7.99 $ 597 Exercisable as of December 31, 2019 1,032,801 $ 4.81 7.20 $ 190

Tangible Stockholder Return P_2

Tangible Stockholder Return Plan (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Fair Value of Performance Plans Assumptions	The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, and the following weighted average assumptions: Year Ended December 31, 2019 2018 Estimated dividend yield 0.00 % 0.00 % Expected volatility 102.14 % 81.73 % Risk-free interest rate 1.87 % 2.75 % Expected life of options (in years) 5.20 5.68 Weighted-average fair value per share $ 1.77 $ 2.06 The fair value of the SARs was estimated using the Black-Scholes option-pricing model for the respective periods, using the following assumptions: July 31, 2019 December 31, 2018 Estimated dividend yield — — Expected volatility 115.82 % 86.71 % Risk-free interest rate 2.07 % 2.63 % Expected term (years) 0.51 1.09 Fair value per share of common stock underlying the SAR $ 2.66 $ 0.83 SAR exercise price $ 3.80 $ 3.80 The fair value of the Performance Plan is estimated at each financial reporting date using the Monte Carlo simulation model and the following assumptions: December 31, 2019 2018 Estimated dividend yield — — Expected volatility 128.30 % 87.19 % Risk-free interest rate 1.53 % 2.47 % Expected term (years) 2.17 3.17 Fair value per share of common stock underlying the Performance Plan $ 0.86 $ 0.83

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Reconciliation of Federal Income Tax Rate to Losses Before Income Tax Benefit	The reasons for the difference between actual income tax benefit for the years ended December 31, 2019 and 2018 , and the amount computed by applying the statutory federal income tax rate to losses before income tax benefit are as follows: Year Ended December 31, 2019 2018 Income tax benefit at federal statutory rate $ (6,435 ) $ (2,661 ) State income taxes, net of federal benefit (582 ) (570 ) Non-deductible expenses 193 154 Federal rate impact — — Change in fair value of warrants 56 (3,479 ) Research and development tax credits (1,225 ) (1,254 ) Other 330 380 Change in valuation allowance 7,663 7,430 Total income tax provision $ — $ —
Significant Components of Company's Deferred Tax Assets and Deferred Tax Liabilities	Significant components of the Company’s deferred tax assets and deferred tax liabilities are as follows: As of December 31, 2019 2018 Deferred tax assets: Accrued compensation $ 13 $ 184 Accrued liabilities 235 149 Tax loss carryforwards 38,042 37,986 Intangible assets 268 286 Share-based compensation 666 814 Tax credits 8,141 6,917 Facility financing lease obligation — 1,847 Research and development service obligation 6,620 — Right-of-use lease liabilities 1,436 — Deferred revenue 572 588 Other 54 10 Total deferred tax assets 56,047 48,781 Less valuation allowance (54,430 ) (46,604 ) Net deferred tax asset 1,617 2,177 Deferred tax liabilities: Fixed assets (1,014 ) (2,032 ) Right-of-use lease assets (421 ) — Other (182 ) (145 ) Net noncurrent deferred tax asset (liability) $ — $ —

Organization and Significant _4

Organization and Significant Accounting Policies - Additional Information (Details)	Jan. 31, 2020shares	Aug. 30, 2019USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Jan. 31, 2020$ / sharesshares	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Feb. 01, 2020$ / shares	Aug. 29, 2019$ / shares	Jan. 01, 2019USD ($)
Organization And Significant Accounting Policies [Line Items]
Accumulated deficit			$ 203,682,000		$ 203,682,000	$ 172,327,000
Cash and cash equivalents			13,711,000		13,711,000	8,194,000
Impairment of long-lived assets					$ 0	0
Life of shelf registration period					3 years
Accrued interest or penalties related to uncertain tax positions			0		$ 0	0
Number of segment | segment					1
Property and equipment, gross			16,185,000		$ 16,185,000	20,456,000
Facility lease obligation			0		0	7,998,000
Right-of-use lease assets capitalized			1,833,000		1,833,000	0
Lease liabilities capitalized			$ 6,262,000		6,262,000
Increase to accumulated deficit									$ 714,000
Amended Sato Agreement
Organization And Significant Accounting Policies [Line Items]
Revenue					$ 4,477,000	$ 5,982,000
Percentage of total revenue generated from Japan licensing partner					91.00%	100.00%
Subsequent event
Organization And Significant Accounting Policies [Line Items]
Closing sale price of common stock (in usd per share) | $ / shares							$ 0.52
Aspire Capital | Common Stock Purchase Agreement
Organization And Significant Accounting Policies [Line Items]
Maximum value of shares of common stock authorized to be sold		$ 25,000,000
Common stock purchase agreement term		30 months
Maximum number of shares that may be sold under agreement (in shares) | shares		5,211,339
Percentage of common stock on date of purchase agreement that cannot be exceeded		19.99%
Closing sale price of common stock (in usd per share) | $ / shares								$ 2.17
Minimum closing sale price to effect purchase of shares (in usd per share) | $ / shares		$ 0.25
Common stock issued during period (in shares) | shares			300,000
Average sales price per share of common stock (in usd per share) | $ / shares			$ 2.49
Shares of common stock issued for commitment fee (in shares) | shares		345,622
Aspire Capital | Common Stock Purchase Agreement | Subsequent event
Organization And Significant Accounting Policies [Line Items]
Common stock issued during period (in shares) | shares	1,345,622			1,000,000
Average sales price per share of common stock (in usd per share) | $ / shares				$ 1.19

Organization and Significant _5

Organization and Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Computer and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	7 years
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	7 years
Building asset under facility lease
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	25 years

Organization and Significant _6

Organization and Significant Accounting Policies - Summary of Anti-dilutive Securities Excluded from Calculation of Weighted Average Common Shares Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Warrants to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	10,000,000	10,000,000
Stock options | 2008 and 2016 Plans
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	1,663,803	1,671,666
Stock options | Inducement Options Outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	125,500	100,500
Stock Appreciation Rights (SARs) | 2016 Stock Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	1,000,000	0

KNOW Bio LLC (Details)

KNOW Bio LLC (Details)	Oct. 13, 2017USD ($)oncovirus	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 30, 2015
Collaborative Arrangements Transactions [Line Items]
Milestone and royalty payments		$ 0	$ 0
KNOW Bio
Collaborative Arrangements Transactions [Line Items]
Percentage of outstanding member interests of KNOW Bio distributed to stockholders				100.00%
Written notice to terminate, period		90 days
Option term for development and commercialization of products rights	3 years
Upfront license agreement payment due upon execution	$ 250,000
KNOW Bio | Maximum
Collaborative Arrangements Transactions [Line Items]
Number of other specified oncoviruses | oncovirus	4

Research and Development Lice_2

Research and Development Licenses (Details) - USD ($)	Jun. 27, 2012	Dec. 31, 2019	Dec. 31, 2018
Research And Development Licenses [Line Items]
Research and development expense		$ 25,172,000	$ 23,045,000
General and administrative expense		10,412,000	11,507,000
Licensing Agreements
Research And Development Licenses [Line Items]
Research and development expense		0	20,000
General and administrative expense		93,000	$ 74,000
Accrual for future payments		$ 0
UNC License Agreement
Research And Development Licenses [Line Items]
License agreement payment in regulatory and commercial milestones (up to)	$ 425,000

Licensing Arrangements (Details

Licensing Arrangements (Details) - Amended Sato Agreement	Nov. 07, 2019JPY (¥)	Nov. 07, 2019USD ($)	Mar. 14, 2019JPY (¥)	Mar. 14, 2019USD ($)	Oct. 23, 2018JPY (¥)	Oct. 23, 2018USD ($)	Oct. 05, 2018USD ($)	Jan. 19, 2017JPY (¥)	Jan. 19, 2017USD ($)	Sep. 13, 2019JPY (¥)	Feb. 14, 2019JPY (¥)	Dec. 31, 2018JPY (¥)	Dec. 31, 2018USD ($)	Oct. 05, 2018JPY (¥)	Jan. 12, 2017JPY (¥)	Jan. 12, 2017USD ($)
Collaborative Arrangements Transactions [Line Items]
Upfront payment receivable														¥ 1,250,000,000
Upfront payment installments										¥ 500,000,000	¥ 500,000,000			250,000,000
Payment received under license agreement	¥ 500,000,000	$ 4,554,000	¥ 500,000,000	$ 4,460,000	¥ 250,000,000	$ 2,224,000		¥ 1,250,000,000	$ 10,813,000
Aggregate development and regulatory milestone payments potentially receivable under license agreement														1,750,000,000	¥ 2,750,000,000
Milestone payment received following initiation of Phase 1 trial												¥ 250,000,000	$ 2,162,000		250,000,000	$ 2,162,000
Aggregate becoming payable upon earlier of specified future dates or achievement of milestone events														1,000,000,000
Aggregate commercial milestone payments potentially receivable under license agreement														¥ 3,900,000,000	¥ 900,000,000
License agreement additional term							2 years
Maximum preclinical studies amount | $							$ 1,000,000
Written notice to terminate, period							120 days
Written notice to terminate due to material breach, term							60 days
Upfront fee refundable in event of termination | $							$ 0

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Details)

Nov. 07, 2019JPY (¥)

Nov. 07, 2019USD ($)

Mar. 14, 2019JPY (¥)

Mar. 14, 2019USD ($)

Oct. 23, 2018JPY (¥)

Oct. 23, 2018USD ($)

Oct. 05, 2018USD ($)

Jan. 19, 2017JPY (¥)

Jan. 19, 2017USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Sep. 30, 2019USD ($)

Sep. 13, 2019JPY (¥)

Aug. 30, 2019USD ($)

Feb. 14, 2019JPY (¥)

Dec. 31, 2018JPY (¥)

Dec. 31, 2018USD ($)

Oct. 05, 2018JPY (¥)

Jan. 12, 2017JPY (¥)

Jan. 12, 2017USD ($)

Disaggregation of Revenue [Line Items]

Performance obligations under long-term contracts unsatisfied

$ 11,504,000

Total revenue

4,896,000

$ 5,991,000

License and collaboration revenue

Disaggregation of Revenue [Line Items]

Revenue

4,477,000

5,982,000

Government research contracts and grants revenue

Disaggregation of Revenue [Line Items]

Total revenue

419,000

0

Research and development services revenue

Disaggregation of Revenue [Line Items]

Revenue

0

9,000

Amended Sato Agreement

Disaggregation of Revenue [Line Items]

Maximum preclinical studies amount

$ 1,000,000

Payment received under license agreement

¥ 500,000,000

$ 4,554,000

¥ 500,000,000

$ 4,460,000

¥ 250,000,000

$ 2,224,000

¥ 1,250,000,000

$ 10,813,000

Milestone payment received following initiation of Phase 1 trial

¥ 250,000,000

$ 2,162,000

¥ 250,000,000

$ 2,162,000

Upfront payment receivable | ¥

¥ 1,250,000,000

Upfront payment installments | ¥

¥ 500,000,000

¥ 500,000,000

250,000,000

Aggregate becoming payable upon earlier of specified future dates or achievement of milestone events | ¥

1,000,000,000

Revenue

4,477,000

5,982,000

Fees paid to third party

228,000

111,000

Aggregate commercial milestone payments potentially receivable under license agreement | ¥

¥ 3,900,000,000

¥ 900,000,000

Amended Sato Agreement | License and collaboration revenue

Disaggregation of Revenue [Line Items]

Revenue

4,477,000

5,982,000

K N O W Bio Services Agreement | Research and development services revenue

Disaggregation of Revenue [Line Items]

Revenue

0

$ 9,000

Other assets | Amended Sato Agreement

Disaggregation of Revenue [Line Items]

License agreement execution expense paid to third party

533,000

Accrued expenses | Amended Sato Agreement

Disaggregation of Revenue [Line Items]

License agreement execution expense paid to third party

230,000

National Institutes of Health

Disaggregation of Revenue [Line Items]

Amount awarded from government grant

$ 223,000

National Institutes of Health | Government research contracts and grants revenue

Disaggregation of Revenue [Line Items]

Total revenue

83,000

U.S. Department of Defense

Disaggregation of Revenue [Line Items]

Amount awarded from government grant

$ 1,113,000

U.S. Department of Defense | Government research contracts and grants revenue

Disaggregation of Revenue [Line Items]

Total revenue

$ 336,000

Revenue Recognition Revenue Rec

Revenue Recognition Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract asset	$ 8,974	$ 17,790
Contract liability, gross	20,478	24,757
Net deferred revenue	11,504	6,967
Deferred revenue, current portion	4,428	4,401
Deferred revenue, net of current portion	$ 7,076	$ 2,566

Revenue Recognition - Performan

Revenue Recognition - Performance Obligations, Expected Timing of Satisfaction (Details)	Dec. 31, 2019	Oct. 04, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated performance period	12 months
Revenue remaining performance obligation percentage	22.00%
Amended Sato Agreement | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2017-02-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated performance period	7 years 6 months	5 years

Research and Development Arra_2

Research and Development Arrangements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	May 04, 2019	Apr. 29, 2019
Ligand Pharmaceuticals Incorporated
Collaborative Arrangements Transactions [Line Items]
Immediate funding			$ 12,000,000
Potential regulatory and commercial milestones payable under agreement			$ 20,000,000
Minimum | Ligand Pharmaceuticals Incorporated
Collaborative Arrangements Transactions [Line Items]
Tiered royalties, percentage			7.00%
Maximum | Ligand Pharmaceuticals Incorporated
Collaborative Arrangements Transactions [Line Items]
Tiered royalties, percentage			10.00%
SB206
Collaborative Arrangements Transactions [Line Items]
Restricted cash related to Funding Agreement	$ 0
SB206 | Ligand Pharmaceuticals Incorporated
Collaborative Arrangements Transactions [Line Items]
Immediate funding			$ 12,000,000
Research and development contra expense	$ (8,185,000)
Restricted Cash | SB206 | Ligand Pharmaceuticals Incorporated
Collaborative Arrangements Transactions [Line Items]
Immediate funding			$ 12,000,000
Reedy Creek Investments LLC
Collaborative Arrangements Transactions [Line Items]
Immediate funding				$ 25,000,000
Additional funding potentially receivable				$ 10,000,000
Initial percentage of fees and milestone to determine quarterly payments per agreement				25.00%
Reedy Creek Investments LLC | Novan, Inc.
Collaborative Arrangements Transactions [Line Items]
Beneficial ownership percentage	15.00%
Reedy Creek Investments LLC | SB206
Collaborative Arrangements Transactions [Line Items]
Percentage used to determine ongoing quarterly payments per agreement				10.00%
Reedy Creek Investments LLC | SB204 And SB414
Collaborative Arrangements Transactions [Line Items]
Percentage used to determine ongoing quarterly payments per agreement				20.00%
Reedy Creek Investments LLC | Cash and Cash Equivalents
Collaborative Arrangements Transactions [Line Items]
Immediate funding				$ 25,000,000
Reedy Creek Investments LLC | Subsequent event
Collaborative Arrangements Transactions [Line Items]
Royalty and milestone agreement funding, amount not expected to be received		$ 10,000,000

Property and Equipment, Net - C

Property and Equipment, Net - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,185	$ 20,456
Less: Accumulated depreciation and amortization	(5,679)	(4,588)
Property and equipment, net	10,506	15,868
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	575	577
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	305	312
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,898	7,442
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	339	400
Building related to facility lease obligation
Property, Plant and Equipment [Line Items]
Property and equipment, gross	0	10,557
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 7,068	$ 1,168

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 2,033	$ 1,664

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) ft² in Thousands, $ in Thousands	1 Months Ended	12 Months Ended		24 Months Ended
	Jul. 31, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2019USD ($)officer	Jan. 01, 2019USD ($)	May 31, 2018ft²	Aug. 31, 2015ft²
Commitments And Contingencies [Line Items]
Weighted average discount rate, operating lease liabilities		9.85%		9.85%
Weighted average remaining lease term, operating leases		6 years 6 months		6 years 6 months
Rentable square feet of facility space | ft²							51,000
Optional term of extending lease agreement							5 years
Current contractual base rent payments per month		$ 95
Percentage of increase in annual rental payments		3.00%
Property and equipment, net		$ 10,506	$ 15,868	$ 10,506
Facility lease obligation		0	7,998	0
Interest expense		2	1,047
Property and equipment, gross		16,185	20,456	16,185
Right-of-use lease assets capitalized		1,833	0	1,833
Lease liabilities capitalized		6,262		$ 6,262
Increase to accumulated deficit					$ 714
Rent expense associated with primary facility lease (Topic 842)		880
Right of use assets obtained in exchange for lease liabilities		1,827	0
Three Former Officers
Commitments And Contingencies [Line Items]
Number of former officers | officer				3
Severance expenses		878	332
Stock compensation expense related to accelerated vesting of former officers stock options		0	212
November 2018 Employee Restructuring
Commitments And Contingencies [Line Items]
Accrued severance costs		52		$ 52
Severance costs expensed during the period		67	196
Sublease Agreement
Commitments And Contingencies [Line Items]
Sublease term	3 years
Monthly rental income	$ 12
Retained Earnings
Commitments And Contingencies [Line Items]
Increase to accumulated deficit					714
ASU 2016-02 (Topic 842)
Commitments And Contingencies [Line Items]
Facility lease obligation					7,998
Right-of-use lease assets capitalized					1,827
Lease liabilities capitalized					6,786
ASU 2016-02 (Topic 842) | Retained Earnings
Commitments And Contingencies [Line Items]
Increase to accumulated deficit					714
Accrued Compensation | Three Former Officers
Commitments And Contingencies [Line Items]
Accrued severance costs		33		33
Building Related to Facility Lease Obligation | ASU 2016-02 (Topic 842)
Commitments And Contingencies [Line Items]
Property and equipment, gross					10,557
Leasehold improvements
Commitments And Contingencies [Line Items]
Property and equipment, gross		7,068	1,168	$ 7,068
Leasehold improvements | ASU 2016-02 (Topic 842)
Commitments And Contingencies [Line Items]
Property and equipment, gross					$ 5,885
Primary Facility Lease
Commitments And Contingencies [Line Items]
Grounds rent expense per month		$ 8
Facility lease obligation			7,998
Interest expense			1,044
Rent expense associated with primary facility lease (Topic 840)			308
Primary Facility Lease | Sublease Agreement
Commitments And Contingencies [Line Items]
Rentable square feet of facility space | ft²						6,400
Primary Facility Lease | Other Accrued Expenses
Commitments And Contingencies [Line Items]
Accrued interest			41
Primary Facility Lease | Building Related to Facility Lease Obligation
Commitments And Contingencies [Line Items]
Property and equipment, estimated useful life		25 years
Property and equipment, net			$ 10,557

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
2020	$ 1,215
2021	1,241
2022	1,278
2023	1,317
2024	1,356
Thereafter	2,111
Total minimum lease payments	8,518
Less imputed interest	(2,256)
Total lease liability	$ 6,262

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	Aug. 30, 2019	Jan. 09, 2018	Aug. 31, 2019	Apr. 30, 2016	Dec. 31, 2019	Sep. 16, 2019	Aug. 29, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Capital stock, shares authorized (in shares)					210,000,000
Common stock, shares authorized (in shares)					200,000,000			200,000,000
Common stock, par value (in USD per share)					$ 0.0001			$ 0.0001
Preferred stock, shares authorized (in shares)					10,000,000			10,000,000
Preferred stock, par value (in USD per share)					$ 0.0001
Shelf registration and public offering, costs capitalized					$ 49,000			$ 49,000
Common stock, shares outstanding (in shares)					26,734,800			26,056,735
Common stock repurchased (in shares)				9,500
Common stock repurchased, value				$ 155,000
Preferred stock, shares outstanding (in shares)					0			0
January 2018 Offering
Class of Stock [Line Items]
Common stock issued during period (in shares)		10,000,000
Price per share (in USD per share)		$ 3.80
Warrant exercise price (in USD per share)		$ 4.66
Warrants expiration period		4 years
Net proceeds from issuance of public offering		$ 35,194,000
Underwriting discounts and commissions and offering expenses		2,806,000
Shelf registration and public offering, costs capitalized		$ 370,000
January 2018 Offering | Maximum
Class of Stock [Line Items]
Warrants issued (in shares)		10,000,000
Shelf Registration
Class of Stock [Line Items]
Shelf registration and public offering, costs capitalized		$ 110,000
Aspire Capital | Common Stock Purchase Agreement
Class of Stock [Line Items]
Maximum value of shares of common stock authorized to be sold	$ 25,000,000
Common stock purchase agreement term	30 months
Common stock registered (in shares)						7,032,630
Maximum shares to be purchased with purchase notice per business day (in shares)	100,000
Maximum aggregate purchase price payable on one purchase date	$ 500,000
Number of shares submitted via purchase notice to trigger a VWAP purchase notice (in shares)	100,000
Maximum percentage of common stock traded on trading day to be purchased	30.00%
Purchase price per share pursuant to VWAP purchase notice as a percentage of VWAP for common stock (in USD per share)	97.00%
Minimum closing sale price to effect purchase of shares (in usd per share)	$ 0.25
Maximum number of shares that may be sold under agreement (in shares)	5,211,339
Percentage of common stock on date of purchase agreement that cannot be exceeded	19.99%
Closing sale price of common stock (in usd per share)							$ 2.17
Shares of common stock issued for commitment fee (in shares)	345,622
Value of commitment fee shares issued			$ 750,000
Common stock issued during period (in shares)					300,000
Average sales price per share of common stock (in usd per share)					$ 2.49
Available for sale under common stock purchase agreement					$ 24,253,000

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock for Future Issuance (Details) - shares	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	13,177,766	12,371,042
2016 Stock Plan
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	388,463	699,376
Warrants to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	10,000,000	10,000,000
Outstanding stock options
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	1,789,303	1,671,666
Stock Appreciation Rights (SARs)
Class of Stock [Line Items]
Common stock shares reserved for future issuance (in shares)	1,000,000	0

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 09, 2018	Dec. 31, 2019	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Warrant exercise limitation, maximum beneficial ownership percentage, current	4.99%
Warrant exercise limitation, maximum beneficial ownership percentage, if elected by holder	9.99%
Beneficial ownership percentage, exception to exercise limitation provision	10.00%
Fundamental transaction common stock acquired threshold	50.00%
Maximum volatility rate used to derive Black-Scholes Value in event of fundamental transaction	100.00%
Warrants exercised (in shares)		0
Change in fair value of warrant liability		$ (264)	$ 16,566
Other income and expense
Class of Warrant or Right [Line Items]
Change in fair value of warrant liability		$ (264)
Warrant liability
Class of Warrant or Right [Line Items]
Warrant fair value per share (in USD per share)		$ 0.15	$ 0.12
January 2018 Offering
Class of Warrant or Right [Line Items]
Common stock issued during period (in shares)	10,000,000
Shares issued, price per share (in USD per share)	$ 3.80
Warrant exercise price (in USD per share)	$ 4.66
Warrants expiration period	4 years
January 2018 Offering | Maximum
Class of Warrant or Right [Line Items]
Warrants issued (in shares)	10,000,000

Warrants - Summary of Warrant L

Warrants - Summary of Warrant Liability Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	$ 1,504	$ 1,240
Warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	1,504	1,240
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	0	0
Significant Other Observable Inputs (Level 2) | Warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	1,504	1,240
Significant Unobservable Inputs (Level 3) | Warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	$ 1,504	$ 1,240

Warrants - Summary of Fair Valu

Warrants - Summary of Fair Value Assumptions for Common Stock Warrants (Details) - Significant Unobservable Inputs (Level 3)	Dec. 31, 2019$ / shares	Dec. 31, 2018$ / shares
Estimated dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	0	0
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	0.0158	0.0246
Expected term (years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected term (years)	2 years 11 days	3 years 7 days
Fair value per share of common stock underlying the warrant
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	0.86	0.83
Warrant exercise price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	4.66	4.66
Warrant | Expected volatility | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	1	0.7774
Warrant | Expected volatility | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption	1.0173	1

Warrants - Summary of Change in

Warrants - Summary of Change in Fair Value of Warrant Liability, Valued Using Significant Unobservable Level 3 Inputs (Details) - Significant Unobservable Inputs (Level 3) - Warrant liability - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 1,240	$ 0
Issuance	0	17,806
Revaluations Included In Earnings	264	(16,566)
Exercises	0	0
Expirations	0	0
Ending Balance	$ 1,504	$ 1,240

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands

Feb. 13, 2020

Feb. 01, 2020

Jan. 06, 2020

Sep. 06, 2019

Jul. 31, 2019

Aug. 08, 2018

May 31, 2018

Jun. 05, 2017

Sep. 20, 2016

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2008

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Additional awards to be granted under the plan (in shares)

0

Shares available for future issuance (in shares)

388,463

699,376

1,023,378

Reclassification from other long-term liabilities to additional paid-in capital

$ 366

$ 366

$ 0

Number of options granted to employees (in shares)

658,030

727,257

Stock options, exercise price at grant date (in USD per share)

$ 2.36

$ 2.97

Share-based compensation expense

$ 1,838

$ 2,204

Total intrinsic value of options exercised

15

95

Total unrecognized compensation expense related to non-vested share based compensation

$ 965

$ 1,036

Weighted average period for nonvested share recognition

11 months 27 days

1 year 9 months 15 days

Subsequent event

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Additional awards to be granted under the plan (in shares)

1,000,000

Fair value per share of common stock underlying the instrument (in USD per share)

$ 0.52

CEO

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Employment agreement, number of SARs granted on a contingent basis (in shares)

1,000,000

SARs

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Exercise price (in USD per share)

$ 3.8

$ 3.8

$ 3.8

Employee share-based compensation expense

$ 507

$ 8

Unrecognized compensation expense related to non-vested SARs

$ 33

Fair value per share of common stock underlying the instrument (in USD per share)

$ 2.66

$ 0.83

SARs | Subsequent event

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Employment agreement, number of SARs granted on a contingent basis (in shares)

600,000

Exercise price (in USD per share)

$ 0.82

2008 Stock Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock shares reserved for future issuance (in shares)

1,416,666

Additional awards to be granted under the plan (in shares)

0

Stock options expiration period

10 years

2016 Stock Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock shares reserved for future issuance (in shares)

833,333

Additional awards to be granted under the plan (in shares)

1,000,000

1,200,000

Maximum aggregate shares to be awarded to one person (in shares)

1,000,000

250,000

Shares available for future issuance (in shares)

388,463

Stock options expiration period

10 years

2016 Stock Plan | Subsequent event

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of options granted to employees (in shares)

383,000

Inducement Grants

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Exercise price (in USD per share)

$ 2.62

Number of options granted to employees (in shares)

25,000

100,500

Stock options, exercise price at grant date (in USD per share)

$ 3.15

Stock options vesting period

3 years

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of SAR Assumptions (Details) - $ / shares	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Aug. 08, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield		0.00%	0.00%
Expected volatility		102.14%	81.73%
Risk-free interest rate		1.87%	2.75%
Expected term (in years)		5 years 2 months 12 days	5 years 8 months 5 days
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield	0.00%		0.00%
Expected volatility	115.82%		86.71%
Risk-free interest rate	2.07%		2.63%
Expected term (in years)	6 months 4 days		1 year 1 month 2 days
Fair value per share of common stock underlying the instrument (in USD per share)	$ 2.66		$ 0.83
SAR exercise price (in USD per share)	$ 3.8		$ 3.8	$ 3.8

Share-Based Compensation - Sc_2

Share-Based Compensation - Schedule of Share-based Compensation Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 1,838	$ 2,204
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	710	1,144
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 1,128	$ 1,060

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value of Option Grant Estimated on Grant Date Using Black-Scholes Option-pricing Model (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Estimated dividend yield	0.00%	0.00%
Expected volatility	102.14%	81.73%
Risk-free interest rate	1.87%	2.75%
Expected life of options (in years)	5 years 2 months 12 days	5 years 8 months 5 days
Weighted-average fair value per share (in USD per share)	$ 1.77	$ 2.06

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Shares Available for Grant
Options outstanding, beginning balance (in shares)	699,376	1,023,378
Additional shares reserved under plan (in shares)		0
Options granted (in shares)	(633,030)	(626,757)
Options forfeited (in shares)	322,117	302,755
Options outstanding, ending balance (in shares)	388,463	699,376
Shares Subject to Outstanding Options
Options outstanding, beginning balance (in shares)	1,671,666	1,399,484
Options granted (in shares)	658,030	727,257
Options forfeited (in shares)	(507,950)	(403,748)
Options exercised (in shares)	(32,443)	(51,327)
Options outstanding, ending balance (in shares)	1,789,303	1,671,666
Vested and expected to vest (in shares)	1,731,437	1,585,689
Exercisable (in shares)	1,032,801	1,007,870
Weighted-Average Exercise Price Per Share
Options outstanding, beginning balance (in USD per share)	$ 5.42	$ 7.17
Options granted (in USD per share)	2.36	2.97
Options forfeited (in USD per share)	7.07	7.61
Options exercised (in USD per share)	2.12	1.16
Options outstanding, ending balance (in USD per share)	3.89	5.42
Vested and expected (in USD per share)	3.94	5.53
Exercisable (in USD per share)	$ 4.81	$ 6.58
Weighted- Average Remaining Contractual Term (in years)
Options outstanding	8 years 11 days
Vested and expected	7 years 11 months 27 days	8 years 1 month 10 days
Exercisable	7 years 2 months 12 days	7 years 6 months 15 days
Aggregate Intrinsic Value
Options outstanding	$ 638
Vested and expected to vest	597	$ 2
Exercisable	$ 190	$ 2

Tangible Stockholder Return P_3

Tangible Stockholder Return Plan - Additional Information (Details) $ / shares in Units, $ in Thousands	Aug. 02, 2018USD ($)tranche$ / shares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield		0.00%	0.00%
Share-based compensation expense		$ 1,838	$ 2,204
Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield		0.00%	0.00%
Share-based compensation expense		$ 291	$ 57
Performance Plan | Deferred Bonus
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of tranches | tranche	2
Number of consecutive trading days	30 days
Share price target, first tranche (in USD per share) | $ / shares	$ 11.17
Bonus pool, first tranche	$ 25,000
Share price target, second tranche (in USD per share) | $ / shares	$ 25.45
Bonus pool, second tranche	$ 50,000
Executive Officer | Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Bonus award payment term	24 months
Employees And Consultants | Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Bonus award payment term	12 months

Tangible Stockholder Return P_4

Tangible Stockholder Return Plan - Fair Value of Performance Plan Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield	0.00%	0.00%
Expected volatility	102.14%	81.73%
Risk-free interest rate	1.87%	2.75%
Expected term (in years)	5 years 2 months 12 days	5 years 8 months 5 days
Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated dividend yield	0.00%	0.00%
Expected volatility	128.30%	87.19%
Risk-free interest rate	1.53%	2.47%
Expected term (in years)	2 years 2 months 1 day	3 years 2 months 1 day
Fair value per share of common stock underlying the instrument (in USD per share)	$ 0.86	$ 0.83

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Income tax benefit	$ 0	$ 0
Provision to income tax expense for TCJA			$ 18,894,000
Impact to effective tax rate		0.00%
Government research and development tax credits	8,141,000	$ 6,917,000
Unrecognized tax benefits	0	$ 0
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Government research and development tax credits	8,141,000
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	165,623,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 165,115,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Income Tax Rate to Losses Before Income Tax Benefit (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax benefit at federal statutory rate	$ (6,435,000)	$ (2,661,000)
State income taxes, net of federal benefit	(582,000)	(570,000)
Non-deductible expenses	193,000	154,000
Federal rate impact	0	0
Change in fair value of warrants	56,000	(3,479,000)
Research and development tax credits	(1,225,000)	(1,254,000)
Other	330,000	380,000
Change in valuation allowance	7,663,000	7,430,000
Total income tax provision	$ 0	$ 0

Income Taxes - Significant Comp

Income Taxes - Significant Components of Company's Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Accrued compensation	$ 13	$ 184
Accrued liabilities	235	149
Tax loss carryforwards	38,042	37,986
Intangible assets	268	286
Share-based compensation	666	814
Tax credits	8,141	6,917
Facility financing lease obligation	0	1,847
Research and development service obligation	6,620	0
Right-of-use lease liabilities	1,436	0
Deferred revenue	572	588
Other	54	10
Total deferred tax assets	56,047	48,781
Less valuation allowance	(54,430)	(46,604)
Net deferred tax asset	1,617	2,177
Deferred tax liabilities:
Fixed assets	(1,014)	(2,032)
Right-of-use lease assets	(421)	0
Other	(182)	(145)
Net noncurrent deferred tax asset (liability)	$ 0	$ 0

Retirement Plan (Details)

Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Employer contribution amount	$ 160	$ 208
Maximum
Defined Contribution Plan Disclosure [Line Items]
Discretionary matching contributions (as a percent)	3.00%	3.00%

Related Party Transactions (Det

Related Party Transactions (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)directorshares	Dec. 31, 2018USD ($)shares
Related Party Transaction [Line Items]
Common stock, number of shares held (in shares)		26,734,800	26,056,735
Research and development expense | $		$ 25,172	$ 23,045
Board Members
Related Party Transaction [Line Items]
Common stock, number of shares held (in shares)		1,002,776	782,083
Malin
Related Party Transaction [Line Items]
Number of directors also affiliated with related party during year | director		2
Malin | Novan, Inc.
Related Party Transaction [Line Items]
Beneficial ownership percentage		10.00%
Cilatus BioPharma AG
Related Party Transaction [Line Items]
Research and development expense | $	$ 250		$ 601
Reedy Creek Investments LLC
Related Party Transaction [Line Items]
Warrants owned (in shares)		3,900,000
Reedy Creek Investments LLC | Novan, Inc.
Related Party Transaction [Line Items]
Beneficial ownership percentage		15.00%

Subsequent Events (Details)

Subsequent Events (Details)

Feb. 13, 2020shares

Feb. 01, 2020$ / sharesshares

Jan. 06, 2020$ / sharesshares

Jul. 31, 2019$ / sharesshares

Aug. 08, 2018$ / sharesshares

Jun. 05, 2017shares

Dec. 31, 2019employeeshares

Dec. 31, 2018$ / sharesshares

Apr. 01, 2020employee

Feb. 29, 2020USD ($)

Feb. 19, 2020USD ($)

Jan. 31, 2020USD ($)

Aug. 30, 2019USD ($)

Apr. 29, 2019USD ($)

Subsequent Event [Line Items]

Additional awards to be granted under the plan (in shares) | shares

0

Number of employees | employee

42

Number of options granted to employees (in shares) | shares

658,030

727,257

National Institutes of Health

Subsequent Event [Line Items]

Amount awarded from government grant | $

$ 223,000

CEO

Subsequent Event [Line Items]

Employment agreement, number of SARs granted on a contingent basis (in shares) | shares

1,000,000

Stock Appreciation Rights (SARs)

Subsequent Event [Line Items]

SAR exercise price (in USD per share) | $ / shares

$ 3.8

$ 3.8

$ 3.8

Closing sale price of common stock (in usd per share) | $ / shares

$ 2.66

$ 0.83

Reedy Creek Investments LLC

Subsequent Event [Line Items]

Additional funding potentially receivable | $

$ 10,000,000

2016 Stock Plan

Subsequent Event [Line Items]

Additional awards to be granted under the plan (in shares) | shares

1,000,000

1,200,000

Subsequent event

Subsequent Event [Line Items]

Additional awards to be granted under the plan (in shares) | shares

1,000,000

Closing sale price of common stock (in usd per share) | $ / shares

$ 0.52

Number of employees | employee

28

Market value of listed securities, minimum requirement | $

$ 50,000,000

Bid price of common stock, minimum requirement | $

$ 1

Subsequent event | National Institutes of Health

Subsequent Event [Line Items]

Amount awarded from government grant | $

$ 1,000,000

Additional amount awarded from government grant | $

$ 500,000

Subsequent event | Stock Appreciation Rights (SARs)

Subsequent Event [Line Items]

Employment agreement, number of SARs granted on a contingent basis (in shares) | shares

600,000

SAR exercise price (in USD per share) | $ / shares

$ 0.82

Subsequent event | Reedy Creek Investments LLC

Subsequent Event [Line Items]

Royalty and milestone agreement funding, amount not expected to be received | $

$ 10,000,000

Subsequent event | 2016 Stock Plan

Subsequent Event [Line Items]

Number of options granted to employees (in shares) | shares

383,000