Aptinyx (APTX) 10-Q 12 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 06, 2020
Document and Entity Information
Entity Registrant Name	Aptinyx Inc.
Entity Central Index Key	0001674365
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		63,256,689
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	APTX
Security Exchange Name	NASDAQ

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 103,810	$ 98,849
Restricted cash	179	179
Accounts receivable	257	444
Prepaid expenses and other current assets	8,836	5,637
Total current assets	113,082	105,109
Other assets	92	166
Property and equipment, net	1,033	1,204
Total assets	114,207	106,479
Current liabilities:
Accounts payable	986	1,555
Accrued expenses and other current liabilities	3,281	3,341
Total current liabilities	4,267	4,896
Other long-term liabilities	154	272
Total liabilities	4,421	5,168
Commitments and contingencies (see Note 10)
Stockholders' equity:
Preferred stock, $0.01 par value, 10,000 shares authorized and no shares issued and outstanding as of September 30, 2020 and December 31, 2019
Common stock, $0.01 par value, 150,000 shares authorized as of September 30, 2020 and December 31, 2019, 47,157 and 33,739 issued and outstanding as of September 30, 2020 and December 31, 2019	471	337
Additional paid-in capital	310,828	263,922
Accumulated deficit	(201,513)	(162,948)
Total stockholders’ equity	109,786	101,311
Total liabilities and stockholders’ equity	$ 114,207	$ 106,479

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Sep. 30, 2020	Dec. 31, 2019
Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	150,000	150,000
Common stock, shares issued	47,157	33,739
Common stock, shares outstanding	47,157	33,739

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Collaboration revenue	$ 257	$ 936	$ 1,564	$ 2,751
Type of Revenue [Extensible List]	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember
Operating expenses:
Research and development	$ 6,630	$ 11,761	$ 26,049	$ 33,732
General and administrative	5,050	4,523	14,719	14,419
Total operating expenses	11,680	16,284	40,768	48,151
Loss from operations	(11,423)	(15,348)	(39,204)	(45,400)
Other income	85	558	639	1,768
Net loss and comprehensive loss	$ (11,338)	$ (14,790)	$ (38,565)	$ (43,632)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.24)	$ (0.44)	$ (0.85)	$ (1.30)
Weighted-average number of common shares outstanding, basic and diluted (in shares)	46,978	33,646	45,503	33,510

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (38,565)	$ (43,632)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	316	345
Stock-based compensation expense	7,503	6,966
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(3,259)	(1,563)
Accounts receivable	187	117
Accounts payable	(559)	(139)
Accrued expenses and other liabilities	(66)	1,279
Net cash used in operating activities	(34,443)	(36,627)
Cash flows from investing activities:
Purchases of property and equipment	(214)	(43)
Net cash used in investing activities	(214)	(43)
Cash flows from financing activities:
Proceeds from stock options exercised	490	282
Proceeds from public offering, net of underwriters' discounts	33,672
Proceeds from at the market offering, net of sales commission	5,799
Payment of offering costs	(417)	(181)
Net cash provided by financing activities	39,544	101
Net increase (decrease) in cash, cash equivalents and restricted cash	4,887	(36,569)
Cash, cash equivalents and restricted cash, at beginning of period	99,194	151,128
Cash, cash equivalents and restricted cash, at end of period	$ 104,081	114,559
Supplemental disclosure of non-cash investing and financing activities:
Offering costs not yet paid		$ 17

Statements of Stockholders' Equ

Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	IPOCommon stock	IPOAdditional paid-in capital	IPO	At The Market Offering ProgramCommon stock	At The Market Offering ProgramAdditional paid-in capital	At The Market Offering Program	Common stock	Additional paid-in capital	Accumulated deficit	Total
Stockholders' (deficit) equity beginning balance at Dec. 31, 2018							$ 333	$ 254,516	$ (105,538)	$ 149,311
Stockholders' (deficit) equity shares beginning balance at Dec. 31, 2018							33,341,000
Stockholders' (Deficit) Equity Rollforward
Issuance of common stock upon vesting of restricted stock							$ 2	(2)
Issuance of common stock upon vesting of restricted stock (in shares)							193,000
Stock-based compensation								6,966		6,966
Issuance of common stock upon exercise of stock options							$ 2	280		282
Issuance of common stock upon exercise of stock options (in shares)							142,000
Net loss									(43,632)	(43,632)
Stockholders' (deficit) equity ending balance at Sep. 30, 2019							$ 337	261,760	(149,170)	112,927
Stockholders' (deficit) equity shares ending balance at Sep. 30, 2019							33,676,000
Stockholders' (deficit) equity beginning balance at Dec. 31, 2018							$ 333	254,516	(105,538)	149,311
Stockholders' (deficit) equity shares beginning balance at Dec. 31, 2018							33,341,000
Stockholders' (Deficit) Equity Rollforward
Issuance of stock, net of sales commission and other offering costs (in shares)						0
Stockholders' (deficit) equity ending balance at Dec. 31, 2019							$ 337	263,922	(162,948)	$ 101,311
Stockholders' (deficit) equity shares ending balance at Dec. 31, 2019							33,739,000			33,739,000
Stockholders' (deficit) equity beginning balance at Jun. 30, 2019							$ 336	259,090	(134,380)	$ 125,046
Stockholders' (deficit) equity shares beginning balance at Jun. 30, 2019							33,608,000
Stockholders' (Deficit) Equity Rollforward
Issuance of common stock upon vesting of restricted stock							$ 1	(1)
Issuance of common stock upon vesting of restricted stock (in shares)							54,000
Stock-based compensation								2,641		2,641
Issuance of common stock upon exercise of stock options								30		30
Issuance of common stock upon exercise of stock options (in shares)							14,000
Net loss									(14,790)	(14,790)
Stockholders' (deficit) equity ending balance at Sep. 30, 2019							$ 337	261,760	(149,170)	112,927
Stockholders' (deficit) equity shares ending balance at Sep. 30, 2019							33,676,000
Stockholders' (deficit) equity beginning balance at Dec. 31, 2019							$ 337	263,922	(162,948)	$ 101,311
Stockholders' (deficit) equity shares beginning balance at Dec. 31, 2019							33,739,000			33,739,000
Stockholders' (Deficit) Equity Rollforward
Issuance of common stock upon vesting of restricted stock (in shares)							23,000
Stock-based compensation								7,503		$ 7,503
Issuance of stock, net of sales commission and other offering costs	$ 117	$ 33,225	$ 33,342	$ 15	$ 5,690	$ 5,705
Issuance of stock, net of sales commission and other offering costs (in shares)	11,692,000			1,491,000		1,491,482
Issuance of common stock upon exercise of stock options							$ 2	488		490
Issuance of common stock upon exercise of stock options (in shares)							212,000
Net loss									(38,565)	(38,565)
Stockholders' (deficit) equity ending balance at Sep. 30, 2020							$ 471	310,828	(201,513)	$ 109,786
Stockholders' (deficit) equity shares ending balance at Sep. 30, 2020							47,157,000			47,157,000
Stockholders' (deficit) equity beginning balance at Jun. 30, 2020							$ 468	307,015	(190,175)	$ 117,308
Stockholders' (deficit) equity shares beginning balance at Jun. 30, 2020							46,850,000
Stockholders' (Deficit) Equity Rollforward
Stock-based compensation								2,669		2,669
Issuance of stock, net of sales commission and other offering costs				$ 3	$ 1,127	$ 1,130
Issuance of stock, net of sales commission and other offering costs (in shares)				299,000
Issuance of common stock upon exercise of stock options								17		17
Issuance of common stock upon exercise of stock options (in shares)							8,000
Net loss									(11,338)	(11,338)
Stockholders' (deficit) equity ending balance at Sep. 30, 2020							$ 471	$ 310,828	$ (201,513)	$ 109,786
Stockholders' (deficit) equity shares ending balance at Sep. 30, 2020							47,157,000			47,157,000

Statements of Stockholders' E_2

Statements of Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
IPO
Discount and other offering costs		$ 1,733
At The Market Offering Program
Discount and other offering costs	$ 37	$ 274

Organization

Organization	9 Months Ended
	Sep. 30, 2020
Organization
Organization	1. Organization Description of business Aptinyx Inc. (the “Company” or “Aptinyx”) was incorporated in Delaware on June 24, 2015 and maintains its headquarters in Evanston, Illinois. Aptinyx is a clinical‑stage biopharmaceutical company focused on the discovery, development, and commercialization of novel, proprietary, synthetic small molecules for the treatment of brain and nervous system disorders. Aptinyx has a platform for discovering proprietary compounds that work through a novel mechanism: modulation of N‑methyl‑D‑aspartate receptors (“NMDAr”), which are vital to normal and effective brain and nervous system functions. This mechanism has applicability across numerous brain and nervous system disorders. Liquidity and capital resources On January 14, 2020, the Company completed a follow-on public offering of its common stock pursuant to an effective registration statement on Form S-3. The Company sold an aggregate of 11,691,666 shares of common stock, which included the exercise in full of the underwriters’ option to purchase additional shares, at a public offering price of $3.00 per share. Net proceeds from the offering were approximately $33.3 million after deducting underwriting discounts and commissions as well as other offering expenses. On July 1, 2019, the Company entered into a Sales Agreement with Cowen and Company, LLC (“Cowen”) pursuant to which the Company may offer and sell shares of its common stock with an aggregate offering price of up to $50.0 million under an “at the market” offering program (the “ATM Offering”). The Sales Agreement provides that Cowen will be entitled to a sales commission equal to 3.0% of the gross sales price per share of all shares sold under the ATM Offering. No sales from the ATM occurred in 2019. For the nine months ended September 30, 2020, the Company sold an aggregate of 1,491,482 shares at a weighted-average price of $3.89 per share for net proceeds of $5.7 million after deducting sales commission and other offering expenses. As of September 30, 2020, the Company had cash and cash equivalents of $103.8 million, which the Company believes will be sufficient to funds its planned operations for a period of at least twelve months from the date of issuance of these condensed financial statements. On October 26, 2020, the Company completed a follow-on public offering of its common stock pursuant to an effective registration statement on Form S-3. The Company sold an aggregate of 16,100,000 shares of common stock, which included the exercise in full of the underwriters’ option to purchase additional shares, at a public offering price of $3.00 per share. Net proceeds from the offering were approximately $45.1 million after deducting underwriting discounts and commissions as well as estimated offering expenses.

Summary of significant accounti

Summary of significant accounting policies	9 Months Ended
	Sep. 30, 2020
Summary of significant accounting policies
Summary of significant accounting policies	2. Basis of presentation The condensed financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. The accompanying condensed financial statements reflect all adjustments consisting of normal, recurring adjustments that are necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods presented. Interim results are not necessarily indicative of results for a full year. Accordingly, these condensed financial statements should be read in conjunction with the financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 (the “Annual Report”) filed with the SEC on March 30, 2020. From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”), or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company, and has elected the extended transition period for complying with new or revised accounting standards, which delays the adoption of these accounting standards until they would apply to private companies. Use of estimates The condensed financial statements are prepared in conformity with GAAP. This process requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Risk and uncertainties The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, uncertainty of: the impact of COVID-19 on future clinical study results, the scope, timing, rate of progress, and expense of the Company’s ongoing as well as any additional preclinical studies, clinical studies, and other research and development activities, clinical study enrollment rate or design, the manufacturing of the Company’s product candidates, significant and changing government regulation, and the timing and receipt of any regulatory approvals. A novel strain of coronavirus (COVID-19) was first identified in December 2019, and subsequently declared a global pandemic by the World Health Organization on March 11, 2020. As a result of the outbreak, many companies have experienced disruptions in their operations and in markets served. On March 27, 2020, the Company suspended patient enrollment for certain ongoing Phase 2 clinical studies, including its NYX-2925 studies in painful diabetic peripheral neuropathy and fibromyalgia and its NYX-483 study in Parkinson’s disease cognitive impairment. The Company began re-enrollment in its NYX-2925 study in fibromyalgia in September 2020. The Company has initiated some and may take additional temporary precautionary measures intended to help ensure the well-being of its employees and minimize business disruption. The Company considered the impact of COVID-19 on the assumptions and estimates used and determined that there were no material adverse impacts on the Company’s results of operations and financial position at September 30, 2020. The full extent of the future impacts of COVID-19 on the Company’s operations is uncertain. A prolonged outbreak could have a material adverse impact on financial results and business operations of the Company, including the availability of capital, timing and ability of the Company to complete certain clinical studies, and other efforts required to advance the development of its targets. Significant accounting policies The Company’s significant accounting policies are described in Note 3, “Summary of significant accounting policies,” in the Annual Report. There have been no material changes to the significant accounting policies during the nine months ended September 30, 2020. Recently issued accounting pronouncement In February 2016, the FASB issued ASU No. 2016‑02, Leases (“ASU 2016‑02”), as amended, which requires a lessee to recognize assets and liabilities on the balance sheet for operating leases and changes many key definitions, including the definition of a lease. The new standard includes a short‑term lease exception for leases with a term of 12 months or less, as part of which a lessee can make an accounting policy election not to recognize lease assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases using classification criteria that are substantially similar to the previous guidance. The new standard will be effective for the Company for annual reporting periods beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company anticipates that the adoption of this standard will have an impact on its balance sheet due to the recognition of right-of-use assets and lease liabilities; however, the Company is currently evaluating the impact that the adoption of ASU 2016-02 may have on its condensed financial statements.

Supplemental financial informat

Supplemental financial information	9 Months Ended
	Sep. 30, 2020
Supplemental financial information
Supplemental financial information	3. Supplemental financial information Cash, cash equivalents and restricted cash Cash and cash equivalents consist of cash and, if applicable, highly liquid investments with an original maturity of three months or less when purchased. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that sum to the total of the same such amounts shown in the condensed statements of cash flows (amounts in thousands). As of As of September 30, December 31, Cash and cash equivalents $ 103,810 $ 98,849 Short-term and long-term restricted cash 271 345 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows $ 104,081 $ 99,194 Prepaid expenses and other current assets Prepaid expenses and other current assets consist of the following (in thousands): As of As of September 30, December 31, Prepaid clinical $ 6,465 $ 3,719 Prepaid insurance 1,470 994 Prepaid manufacturing costs 558 558 Other prepaid expenses and current assets 343 366 Total prepaid expenses and other current assets $ 8,836 $ 5,637 Accrued expenses and other current liabilities Accrued expenses and other current liabilities consist of the following (in thousands): As of As of September 30, December 31, Employee-related expenses $ 1,483 $ 1,925 Development costs and sponsored research 843 652 Clinical trials 190 410 Professional services 328 206 Other 437 148 Total accrued expenses and other current liabilities $ 3,281 $ 3,341

Research collaboration agreemen

Research collaboration agreement with Allergan	9 Months Ended
	Sep. 30, 2020
Research collaboration agreement with Allergan
Research collaboration agreement with Allergan	4. Research collaboration agreement with Allergan On July 24, 2015, the Company entered into a Research Collaboration Agreement (“RCA”) with Naurex Inc., a subsidiary of Allergan plc (“Allergan”), which became a wholly owned subsidiary of AbbVie Inc. in May 2020. The RCA is focused on the research and discovery of small molecules that modulate NMDArs. The collaboration is supervised by a Joint Steering Committee (“JSC”) comprising an equal number of representatives from both the Company and Allergan. Under the terms of the agreement, the RCA will terminate upon the earlier of (i) 180 days after a predetermined anniversary of the effective date of the RCA and (ii) the date on which Allergan exercises the last of three options to acquire molecules from a pool of eligible compounds in both cases (clauses (i) and (ii)) subject to potential extension if and as required for the Company to transfer to Allergan information and technology related to compounds that were licensed by Allergan. The jointly funded research activities under the RCA and the associated payments by Allergan to the Company came to their contractual conclusion in accordance with the agreement in the third quarter of 2020. Under the terms of the agreement, Allergan will pay the Company $1.0 million for each option exercised by Allergan. On May 16, 2018, Allergan exercised its option to acquire exclusive rights to develop and commercialize AGN-241751 within a predefined set of indications. The Company concluded that Allergan meets the definition of a customer, and therefore concluded that the RCA represents a contract with a customer that falls within the scope of ASC 606. Performance obligations The Company identified the following promised goods or services within the RCA: · Research Licenses – the Company provides access to exclusive licenses under all of the Company’s NMDAr technologies, during the research term for the sole purpose of conducting research and development activities (the “Research Licenses”). Historically, the Company’s licenses have held no value to the customer on a standalone basis, as the research compounds were in the early discovery phase and required the Company’s expertise for further development. Accordingly, the Research Licenses are not considered distinct. · Research and Development Services – the Company provides research and development services that are performed on behalf of, or with, Allergan (the “Research and Development Services”). As discussed within Research Licenses above, the Company’s licenses have historically held no value without the specialized Research and Development Services. As the Company generally only provides Research and Development Services for internally generated small molecules that modulate NMDArs which require a license to be utilized by a third party, the Research and Development Services are not considered distinct. · Joint Steering Committee – the Company actively participates in a joint steering committee, which allows the Company and its collaboration partner to direct the progression and prioritization of the joint discovery programs. As the JSC would not occur or benefit the customer without the use of the Research Licenses and the related Research and Development Services, and given the Company’s proprietary knowledge of the Research Licenses and the NMDAr technologies, this is not considered distinct. The Company also evaluated whether the option granted to the customer to acquire additional goods or services represented a material right at contract inception. Upon Allergan’s exercise of one of its options, the Company is obligated to transfer control of all intellectual property relating to the optioned compound to Allergan, after which the Company has no further interest in, or continuing involvement with, such optioned compound. The Company evaluated the customer options for material rights, that is, whether the option was to acquire additional goods or services for free or at a discount, and concluded that the options are priced, at contract inception, at standalone selling price. Consequently, the customer options do not represent a performance obligation at the outset of the arrangement since they are contingent upon the option exercise which is outside of the Company’s control. The Company has concluded that there is a single combined performance obligation (comprising the Research Licenses, Research and Development Services, and participation in the JSC) which is satisfied over time, as the Research and Development Services are performed. The exercise of the option to acquire exclusive rights to develop and commercialize AGN-241751 or any future options exercised are not considered a performance obligation until the time of option exercise. Transaction price The RCA includes both fixed and variable consideration. Fixed payments, such as contractually defined fees per full-time employee (“FTE”), are included in the transaction price at contract inception, while variable consideration, such as reimbursement for Research and Development Services, are estimated and then evaluated for constraints upon inception of the contract and evaluated on a quarterly basis thereafter. Research and Development Services are updated for actual invoices. There were no capitalized costs associated with obtaining the contract. The Company concluded that it will use an input method to measure proportional performance and to calculate the corresponding amount of revenue to recognize. The Company uses fixed FTE efforts and variable out-of-pocket costs as actual costs incurred relative to the annual budget research plan to measure progress towards fulfillment of the performance obligation. An input method of revenue recognition requires management to make estimates of costs to complete the Company’s performance obligations. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete the Company’s performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated. The Company does not anticipate significant changes as the research plan is reviewed and adjusted annually and approved by the JSC. There are no significant financing components in the contract. The Company has determined that the option fee is representative of standalone selling price and concluded that it will recognize revenue for the option fee at a point in time, on the date of exercise, due to the significant uncertainty of whether or not Allergan would exercise the option. The Company recognizes the option fee at a point in time because control of the underlying intellectual property transfers to the customer, and the customer is able to use and benefit from the license. The Company has no further rights, interests, or remaining performance obligations associated with any optioned compound, once exercised. During the three months ended September 30, 2020 and 2019, the Company recorded expenses of $0.6 million and $1.9 million, respectively, for certain development activities in accordance with the terms of the RCA, of which 50% was reimbursed by Allergan. The Company received reimbursements of $0.3 million and $0.9 million during the three months ended September 30, 2020 and 2019, respectively. During the nine months ended September 30, 2020 and 2019, the Company recorded expenses of $3.1 million and $5.5 million, respectively, for certain development activities in accordance with the terms of the RCA, of which 50% was reimbursed by Allergan. The Company received reimbursements of $1.6 million and $2.8 million during the nine months ended September 30, 2020 and 2019, respectively. Such reimbursements were reported within revenue in the condensed statements of operations. All of the Company’s accounts receivable as of both September 30, 2020 and December 31, 2019 relate to amounts owed by Allergan under the RCA.

Fair value measurements

Fair value measurements	9 Months Ended
	Sep. 30, 2020
Fair value measurements
Fair value measurements	5. Fair value measurements ASC 820, Fair Value Measurement (“ASC 820”), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: · Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; · Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; and · Level 3 inputs are unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The carrying values reported in the Company’s balance sheets for cash and cash equivalents, restricted cash, accounts receivable, accounts payable, and accrued expenses are reasonable estimates of their fair values due to the short-term nature of these items. Assets measured at fair value as of September 30, 2020 are as follows (in thousands): September 30, Level 1 Level 2 Level 3 Assets Money market funds, included in cash and cash equivalents $ 102,710 $ 102,710 $ — $ — Money market funds, included in restricted cash 179 179 — — Money market funds, included in other assets 92 92 — — $ 102,981 $ 102,981 $ — $ — Assets measured at fair value as of December 31, 2019 are as follows (in thousands): December 31, Level 1 Level 2 Level 3 Assets Money market funds, included in cash and cash equivalents $ 97,998 $ 97,998 $ — $ — Money market funds, included in restricted cash 179 179 — — Money market funds, included in other assets 166 166 — — $ 98,343 $ 98,343 $ — $ —

Property and equipment, net

Property and equipment, net	9 Months Ended
	Sep. 30, 2020
Property and equipment, net
Property and equipment, net	6 . Property and equipment, net Property and equipment are as follows (in thousands): As of As of September 30, December 31, Computer software and equipment $ 15 $ 15 Office equipment and furniture 176 176 Laboratory equipment 1,801 1,597 Leasehold improvements 1,062 1,051 Construction-in-progress — 11 Less accumulated depreciation (2,021) (1,646) Property and equipment, net $ 1,033 $ 1,204 Depreciation expense was $0.1 million for each of the three months ended September 30, 2020 and 2019, respectively, and $0.4 million for each of the nine months ended September 30, 2020 and 2019, respectively .

Stock incentive plan

Stock incentive plan	9 Months Ended
	Sep. 30, 2020
Stock incentive plan
Stock incentive plan	7. Stock incentive plans On June 5, 2018, the Company’s stockholders approved the 2018 Stock Option and Incentive Plan (the “2018 Plan”), which became effective on June 20, 2018. The 2018 Plan provides for an annual increase, to be added on the first day of each fiscal year, of up to 4% of the Company’s outstanding shares of common stock as of the last day of the prior year. On January 1, 2020, 1,349,165 shares of common stock were added to the 2018 Plan. The number of shares available for grant under the Company’s 2018 Plan as of September 30, 2020 was 2,226,327. Stock‑based compensation expense Non-cash stock-based compensation expense recognized in the accompanying condensed statements of operations relating to stock options, restricted stock awards, and restricted stock units for the three and nine months ended September 30, 2020 and 2019 was as follows (in thousands): Three months ended Nine months ended September 30, September 30, Research and development $ 645 $ 816 $ 1,660 $ 2,181 General and administrative 2,024 1,825 5,843 4,785 Total stock‑based compensation expense $ 2,669 $ 2,641 $ 7,503 $ 6,966 Stock options The table below summarizes activity related to stock options (in thousands, except per share amounts): Weighted‑ Weighted‑ average average remaining Aggregate exercise contractual intrinsic Options Shares price term value Outstanding, December 31, 2019 4,798 $ 8.75 8.29 $ 1,159 Granted 2,405 3.12 Exercised (212) 2.32 Forfeited and canceled (326) 8.96 Outstanding, September 30, 2020 6,665 $ 6.91 8.25 $ 1,547 Vested and expected to vest at September 30, 2020 6,665 $ 6.91 8.25 $ 1,547 Exercisable at September 30, 2020 3,022 $ 7.15 7.55 $ 826 During the nine months ended September 30, 2020 and 2019, the Company granted 2.4 million and 1.7 million stock options, respectively and these options had a weighted-average grant-date fair value of $2.06 and $8.36 per share, respectively. The weighted-average grant-date fair value of options was determined using the Black-Scholes option-pricing model. The assumptions used in the Black-Scholes option-pricing model for options granted during the nine months ended September 30, 2020 were similar to those as described in the Annual Report. As of September 30, 2020, there was $15.3 million of total unrecognized stock-based compensation expense related to non-vested stock options which is expected to be recognized over a weighted-average period of 2.3 years. The options have a ten-year life and generally vest over a period of four years, subject to continuous employment. Restricted stock awards During the nine months ended September 30, 2020, the Company issued 6,392 restricted stock awards to a board member that vested immediately on the date of grant. Non-cash restricted stock award expense recognized in the accompanying condensed statements of operations was less than $0.1 million for the nine months ended September 30, 2020 and $0.3 million for the nine months ended September 30, 2019 . The total fair value of the shares that vested was less than $0.1 million in the nine months ended September 30, 2020 and $0.2 million in the nine months ended September 30, 2019. At September 30, 2020, there are no unvested restricted stock awards. Restricted stock units In June 2020 and May 2019, the Company issued an aggregate of 205,200 and 1,183,400 restricted stock units, respectively, to employees. The restricted stock units issued in 2020 vest ten months from the date of grant. The restricted stock units issued in 2019 vest two years from the date of grant. The Company at any time may accelerate the vesting of the restricted stock units. Such shares are not accounted for as outstanding until they vest. The table below summarizes activity related to restricted stock units (in thousands, except per share amounts): Weighted‑ average grant date fair value Shares per share Unvested as of December 31, 2019 1,032 $ 3.63 Issued 205 $ 3.61 Vested (21) 3.63 Forfeited and canceled (88) 3.63 Unvested as of September 30, 2020 1,128 $ 3.63 Non-cash restricted stock unit award expense recognized in the accompanying condensed statements of operations was $0.6 million for each of the three months ended September 30, 2020 and 2019, respectively, and $1.5 million and $0.8 million for the nine months ended September 30, 2020 and 2019, respectively. At September 30, 2020, there was $1.5 million of unrecognized stock-based compensation related to 1,128,300 unvested restricted stock units that will be recognized as expense over a weighted-average period of 0.6 years.

Net loss per share

Net loss per share	9 Months Ended
	Sep. 30, 2020
Net loss per share
Net loss per share	8. Net loss per share Basic and diluted net loss per share attributable to common stockholders was calculated as follows for the three and nine months ended September 30, 2020 and 2019 (in thousands, except per share data): Three months ended Nine months ended September 30, September 30, Numerator: Net loss attributable to common stockholders $ (11,338) $ (14,790) $ (38,565) $ (43,632) Denominator: Weighted-average common shares outstanding—basic and diluted 46,978 33,646 45,503 33,510 Net loss per share attributable to common stockholders—basic and diluted $ (0.24) $ (0.44) $ (0.85) $ (1.30) The following common stock equivalents outstanding as of September 30, 2020 and 2019, were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti‑dilutive (in thousands): As of September 30, Stock options issued and outstanding 6,665 4,958 Unvested restricted stock 1,128 1,159 Total 7,793 6,117

Income taxes

Income taxes	9 Months Ended
	Sep. 30, 2020
Income taxes
Income taxes	9. Income taxes Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, including its net operating losses. Based on its history of operating losses, the Company believes that it is more likely than not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of September 30, 2020 and December 31, 2019. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted in the United States. The CARES Act, among other things, permits net operating loss (“NOL”) carryovers and carrybacks to offset 100% of taxable income for taxable years beginning before 2021. Previously, NOLs generated after December 31, 2017 were limited to 80% of taxable income in future years. In addition, the CARES Act allows NOLs incurred in 2018, 2019 and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. The NOL carryback provision of the CARES Act had no impact on the Company due to its tax losses generated during all prior years.

Commitments and contingencies

Commitments and contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and contingencies
Commitments and contingencies	10. Commitments and contingencies Contingencies From time to time, the Company may be subject to occasional lawsuits, investigations, and claims arising out of the normal conduct of business. The Company has no significant pending or threatened litigation as of September 30, 2020. Indemnifications In the normal course of business, the Company enters into contracts that contain a variety of indemnifications with its employees, licensors, suppliers and service providers. Further, the Company indemnifies its directors and officers who are, or were, serving at the Company’s request in such capacities. The Company’s maximum exposure under these arrangements is unknown at September 30, 2020. The Company does not anticipate recognizing any significant losses relating to these arrangements. Leases The Company enters into various non-cancelable, operating lease agreements for its facilities and equipment in order to conduct its operations. The Company expenses rent on a straight-line basis over the life of the lease and has recorded deferred rent on the Company’s balance sheets within both accrued expenses and other current liabilities and other long-term liabilities. Total rent expense, inclusive of lease incentives, under all the operating lease agreements amounted to $0.3 million and $0.2 million for the three months ended September 30, 2020 and 2019, respectively, and $0.7 million and $0.6 million for the nine months ended September 30, 2020 and 2019, respectively .

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events
Subsequent Events	11. On October 26, 2020, the Company completed a follow-on public offering of its common stock pursuant to an effective registration statement on Form S-3. The Company sold an aggregate of 16,100,000 shares of common stock, which included the exercise in full of the underwriters’ option to purchase additional shares, at a public offering price of $3.00 per share. Net proceeds from the offering were approximately $45.1 million after deducting underwriting discounts and commissions as well as estimated offering expenses.

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2020
Summary of significant accounting policies
Use of estimates	Use of estimates The condensed financial statements are prepared in conformity with GAAP. This process requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.
Risk and uncertainties	Risk and uncertainties The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, uncertainty of: the impact of COVID-19 on future clinical study results, the scope, timing, rate of progress, and expense of the Company’s ongoing as well as any additional preclinical studies, clinical studies, and other research and development activities, clinical study enrollment rate or design, the manufacturing of the Company’s product candidates, significant and changing government regulation, and the timing and receipt of any regulatory approvals. A novel strain of coronavirus (COVID-19) was first identified in December 2019, and subsequently declared a global pandemic by the World Health Organization on March 11, 2020. As a result of the outbreak, many companies have experienced disruptions in their operations and in markets served. On March 27, 2020, the Company suspended patient enrollment for certain ongoing Phase 2 clinical studies, including its NYX-2925 studies in painful diabetic peripheral neuropathy and fibromyalgia and its NYX-483 study in Parkinson’s disease cognitive impairment. The Company began re-enrollment in its NYX-2925 study in fibromyalgia in September 2020. The Company has initiated some and may take additional temporary precautionary measures intended to help ensure the well-being of its employees and minimize business disruption. The Company considered the impact of COVID-19 on the assumptions and estimates used and determined that there were no material adverse impacts on the Company’s results of operations and financial position at September 30, 2020. The full extent of the future impacts of COVID-19 on the Company’s operations is uncertain. A prolonged outbreak could have a material adverse impact on financial results and business operations of the Company, including the availability of capital, timing and ability of the Company to complete certain clinical studies, and other efforts required to advance the development of its targets.
Recent adopted and issued accounting pronouncements	Recently issued accounting pronouncement In February 2016, the FASB issued ASU No. 2016‑02, Leases (“ASU 2016‑02”), as amended, which requires a lessee to recognize assets and liabilities on the balance sheet for operating leases and changes many key definitions, including the definition of a lease. The new standard includes a short‑term lease exception for leases with a term of 12 months or less, as part of which a lessee can make an accounting policy election not to recognize lease assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases using classification criteria that are substantially similar to the previous guidance. The new standard will be effective for the Company for annual reporting periods beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company anticipates that the adoption of this standard will have an impact on its balance sheet due to the recognition of right-of-use assets and lease liabilities; however, the Company is currently evaluating the impact that the adoption of ASU 2016-02 may have on its condensed financial statements.

Supplemental financial inform_2

Supplemental financial information (Tables)	9 Months Ended
	Sep. 30, 2020
Supplemental financial information
Schedule of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that sum to the total of the same such amounts shown in the condensed statements of cash flows (amounts in thousands). As of As of September 30, December 31, Cash and cash equivalents $ 103,810 $ 98,849 Short-term and long-term restricted cash 271 345 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows $ 104,081 $ 99,194
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consist of the following (in thousands): As of As of September 30, December 31, Prepaid clinical $ 6,465 $ 3,719 Prepaid insurance 1,470 994 Prepaid manufacturing costs 558 558 Other prepaid expenses and current assets 343 366 Total prepaid expenses and other current assets $ 8,836 $ 5,637
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): As of As of September 30, December 31, Employee-related expenses $ 1,483 $ 1,925 Development costs and sponsored research 843 652 Clinical trials 190 410 Professional services 328 206 Other 437 148 Total accrued expenses and other current liabilities $ 3,281 $ 3,341

Fair value measurements (Tables

Fair value measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair value measurements
Schedule of assets measured at fair value	Assets measured at fair value as of September 30, 2020 are as follows (in thousands): September 30, Level 1 Level 2 Level 3 Assets Money market funds, included in cash and cash equivalents $ 102,710 $ 102,710 $ — $ — Money market funds, included in restricted cash 179 179 — — Money market funds, included in other assets 92 92 — — $ 102,981 $ 102,981 $ — $ — Assets measured at fair value as of December 31, 2019 are as follows (in thousands): December 31, Level 1 Level 2 Level 3 Assets Money market funds, included in cash and cash equivalents $ 97,998 $ 97,998 $ — $ — Money market funds, included in restricted cash 179 179 — — Money market funds, included in other assets 166 166 — — $ 98,343 $ 98,343 $ — $ —

Property and equipment, net (Ta

Property and equipment, net (Tables)	9 Months Ended
	Sep. 30, 2020
Property and equipment, net
Schedule of property and equipment, net	Property and equipment are as follows (in thousands): As of As of September 30, December 31, Computer software and equipment $ 15 $ 15 Office equipment and furniture 176 176 Laboratory equipment 1,801 1,597 Leasehold improvements 1,062 1,051 Construction-in-progress — 11 Less accumulated depreciation (2,021) (1,646) Property and equipment, net $ 1,033 $ 1,204

Stock incentive plan (Tables)

Stock incentive plan (Tables)	9 Months Ended
	Sep. 30, 2020
Stock incentive plan
Allocation of stock-based compensation expenses	Non-cash stock-based compensation expense recognized in the accompanying condensed statements of operations relating to stock options, restricted stock awards, and restricted stock units for the three and nine months ended September 30, 2020 and 2019 was as follows (in thousands): Three months ended Nine months ended September 30, September 30, Research and development $ 645 $ 816 $ 1,660 $ 2,181 General and administrative 2,024 1,825 5,843 4,785 Total stock‑based compensation expense $ 2,669 $ 2,641 $ 7,503 $ 6,966
Schedule of restricted stock unit activity	The table below summarizes activity related to restricted stock units (in thousands, except per share amounts): Weighted‑ average grant date fair value Shares per share Unvested as of December 31, 2019 1,032 $ 3.63 Issued 205 $ 3.61 Vested (21) 3.63 Forfeited and canceled (88) 3.63 Unvested as of September 30, 2020 1,128 $ 3.63
Summary of stock option activity	The table below summarizes activity related to stock options (in thousands, except per share amounts): Weighted‑ Weighted‑ average average remaining Aggregate exercise contractual intrinsic Options Shares price term value Outstanding, December 31, 2019 4,798 $ 8.75 8.29 $ 1,159 Granted 2,405 3.12 Exercised (212) 2.32 Forfeited and canceled (326) 8.96 Outstanding, September 30, 2020 6,665 $ 6.91 8.25 $ 1,547 Vested and expected to vest at September 30, 2020 6,665 $ 6.91 8.25 $ 1,547 Exercisable at September 30, 2020 3,022 $ 7.15 7.55 $ 826

Net loss per share (Tables)

Net loss per share (Tables)	9 Months Ended
	Sep. 30, 2020
Net loss per share
Schedule of basic and diluted net loss per share attributable to common stockholders calculation	Basic and diluted net loss per share attributable to common stockholders was calculated as follows for the three and nine months ended September 30, 2020 and 2019 (in thousands, except per share data): Three months ended Nine months ended September 30, September 30, Numerator: Net loss attributable to common stockholders $ (11,338) $ (14,790) $ (38,565) $ (43,632) Denominator: Weighted-average common shares outstanding—basic and diluted 46,978 33,646 45,503 33,510 Net loss per share attributable to common stockholders—basic and diluted $ (0.24) $ (0.44) $ (0.85) $ (1.30)
Schedule of anti-dilutive securities excluded from computation of diluted net loss per share	The following common stock equivalents outstanding as of September 30, 2020 and 2019, were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti‑dilutive (in thousands): As of September 30, Stock options issued and outstanding 6,665 4,958 Unvested restricted stock 1,128 1,159 Total 7,793 6,117

Organization (Details)

Organization (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 26, 2020	Jan. 14, 2020	Jul. 01, 2019	Sep. 30, 2020	Dec. 31, 2019
Organization
Common stock issued and sold in public offering (in shares)		11,691,666
Public offering price of the shares sold		$ 3
Proceeds from public offering, net of underwriters' discounts		$ 33,300		$ 5,799
Cash and cash equivalents				$ 103,810	$ 98,849
Expected period of sufficient funds for planned operations				12 months
Subsequent Event
Organization
Common stock issued and sold in public offering (in shares)	16,100,000
Public offering price of the shares sold	$ 3
Proceeds from public offering, net of underwriters' discounts	$ 45,100
At The Market Offering Program
Organization
Common stock issued and sold in public offering (in shares)				1,491,482	0
Public offering price of the shares sold				$ 3.89
Proceeds from public offering, net of underwriters' discounts				$ 5,700
Threshold shares agreed to be sold			$ 50,000
Sales commission percentage			3.00%

Supplemental financial inform_3

Supplemental financial information - Cash, cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Supplemental financial information
Cash and cash equivalents	$ 103,810	$ 98,849
Short-term and long-term restricted cash	271	345
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 104,081	$ 99,194	$ 114,559	$ 151,128

Supplemental financial inform_4

Supplemental financial information - Prepaid expenses and other current assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Supplemental financial information
Prepaid clinical	$ 6,465	$ 3,719
Prepaid insurance	1,470	994
Prepaid Manufacturing Cost	558	558
Other prepaid expenses and current assets	343	366
Total prepaid expenses and other current assets	$ 8,836	$ 5,637

Supplemental financial inform_5

Supplemental financial information - Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Supplemental financial information
Employee-related expenses	$ 1,483	$ 1,925
Development costs and sponsored research	843	652
Clinical trials	190	410
Professional services	328	206
Other	437	148
Total accrued expenses and other current liabilities	$ 3,281	$ 3,341

Research collaboration agreem_2

Research collaboration agreement with Allergan (Details) $ in Thousands	Jul. 24, 2015USD ($)Option	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Research collaboration agreement with Allergan
Research and development		$ 6,630	$ 11,761	$ 26,049	$ 33,732
RCA
Research collaboration agreement with Allergan
Agreement term	180 days
Number of options to acquire molecules | Option	3
Payment of option exercise fee	$ 1,000
Capitalized contract costs		0		0
Research and development		$ 600	$ 1,900	$ 3,100	$ 5,500
Development activities reimbursement percentage		50.00%	50.00%	50.00%	50.00%
Development activities expenses reimbursed		$ 300	$ 900	$ 1,600	$ 2,800

Fair value measurements (Detail

Fair value measurements (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair value measurements
Assets measured at fair value	$ 102,981	$ 98,343
Money market funds, included in cash and cash equivalents
Fair value measurements
Money market funds	102,710	97,998
Money market funds, included in restricted cash
Fair value measurements
Money market funds	179	179
Money market funds, included in other assets
Fair value measurements
Money market funds	92	166
Level 1
Fair value measurements
Assets measured at fair value	102,981	98,343
Level 1 | Money market funds, included in cash and cash equivalents
Fair value measurements
Money market funds	102,710	97,998
Level 1 | Money market funds, included in restricted cash
Fair value measurements
Money market funds	179	179
Level 1 | Money market funds, included in other assets
Fair value measurements
Money market funds	$ 92	$ 166

Property and equipment, net (De

Property and equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Property and equipment
Less accumulated depreciation	$ (2,021)		$ (2,021)		$ (1,646)
Property and equipment, net	1,033		1,033		1,204
Depreciation	100	$ 100	400	$ 400
Computer software and equipment
Property and equipment
Property and equipment, gross	15		15		15
Office equipment and furniture
Property and equipment
Property and equipment, gross	176		176		176
Laboratory equipment
Property and equipment
Property and equipment, gross	1,801		1,801		1,597
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 1,062		$ 1,062		1,051
Construction-in-progress
Property and equipment
Property and equipment, gross					$ 11

Stock incentive plan (Details)

Stock incentive plan (Details) - 2018 Plan	9 Months Ended
	Sep. 30, 2020shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of increase in number of shares outstanding	4.00%
Common stock added to plan	1,349,165
Awards available for future grant	2,226,327

Stock incentive plan - Stock-ba

Stock incentive plan - Stock-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,669	$ 2,641	$ 7,503	$ 6,966
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	645	816	1,660	2,181
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,024	$ 1,825	$ 5,843	$ 4,785

Stock incentive plan - Activity

Stock incentive plan - Activity related to stock options (Details) - Stock options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Shares
Outstanding, at the beginning of the period	4,798
Granted	2,405	1,700
Exercised	(212)
Forfeited and canceled	(326)
Outstanding, at the end of the period	6,665		4,798
Vested and expected to vest	6,665
Exercisable	3,022
Weighted-average exercise price
Outstanding, at the beginning of the period	$ 8.75
Granted	3.12
Exercised	2.32
Forfeited and canceled	8.96
Outstanding, at the end of the period	6.91		$ 8.75
Vested and expected to vest	6.91
Exercisable at the end of the period	$ 7.15
Weighted-average remaining contractual term
Weighted-average remaining contractual term	8 years 3 months		8 years 3 months 15 days
Vested and expected to vest	8 years 3 months
Exercisable	7 years 6 months 18 days
Aggregate intrinsic value
Outstanding, at the beginning of the period	$ 1,159
Outstanding, at the end of the period	1,547		$ 1,159
Vested and expected to vest	1,547
Exercisable	$ 826
Weighted-average grant date fair value per share	$ 2.06	$ 8.36
Unrecognized stock-based compensation related to non-vested stock options	$ 15,300
Expenses recognized over a weighted-average period (in years)	2 years 3 months 18 days
Term of award	10 years
Vesting period	4 years

Stock incentive plan - Restrict

Stock incentive plan - Restricted stock awards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash restricted stock unit award expense recognized	$ 2,669	$ 2,641	$ 7,503	$ 6,966
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash restricted stock unit award expense recognized				300
Fair value of shares vested				$ 200
Unvested restricted stock outstanding	0		0
Restricted stock awards | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			6,392
Restricted stock awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash restricted stock unit award expense recognized			$ 100
Fair value of shares vested			$ 100

Stock incentive plan - Restri_2

Stock incentive plan - Restricted stock units (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2020	May 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Weighted-average grant date fair value per share
Non-cash restricted stock unit award expense recognized			$ 2,669	$ 2,641	$ 7,503	$ 6,966
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	10 months	2 years
Shares
Unvested at beginning of period (in shares)					1,032,000
Issued (in shares)	205,200	1,183,400			205,000
Vested					(21,000)
Forfeited and canceled (in shares)					(88,000)
Unvested at end of period (in shares)			1,128,300		1,128,300
Weighted-average grant date fair value per share
Unvested at beginning of period (in dollars per share)					$ 3.63
Issued (in dollars per share)					3.61
Vested (in dollars per share)					3.63
Forfeited and canceled (in dollars per share)					3.63
Unvested at end of period (in dollars per share)			$ 3.63		$ 3.63
Non-cash restricted stock unit award expense recognized			$ 600	$ 600	$ 1,500	$ 800
Unrecognized compensation related to unvested restricted stock units			$ 1,500		$ 1,500
Expenses recognized over a weighted-average period (in years)					7 months 6 days

Net loss per share (Details)

Net loss per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss attributable to common stockholders	$ (11,338)	$ (14,790)	$ (38,565)	$ (43,632)
Denominator:
Weighted-average common shares outstanding—basic and diluted	46,978	33,646	45,503	33,510
Net loss per share attributable to common stockholders—basic and diluted	$ (0.24)	$ (0.44)	$ (0.85)	$ (1.30)

Net loss per share - Anti-dilut

Net loss per share - Anti-dilutive securities (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Common stock equivalents outstanding excluded from the computation of diluted net loss per share attributable to common stockholders
Outstanding anti-dilutive securities excluded from computation of diluted net loss per share	7,793	6,117
Stock options
Common stock equivalents outstanding excluded from the computation of diluted net loss per share attributable to common stockholders
Outstanding anti-dilutive securities excluded from computation of diluted net loss per share	6,665	4,958
Unvested restricted stock
Common stock equivalents outstanding excluded from the computation of diluted net loss per share attributable to common stockholders
Outstanding anti-dilutive securities excluded from computation of diluted net loss per share	1,128	1,159

Commitments and contingencies (

Commitments and contingencies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Commitments and contingencies
Rent expense inclusive of lease incentives	$ 0.3	$ 0.2	$ 0.7	$ 0.6

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 26, 2020	Jan. 14, 2020	Sep. 30, 2020
Subsequent Event [Line Items]
Number of common stock shares newly issued		11,691,666
Public offering price of the shares sold		$ 3
Proceeds from public offering, net of underwriters' discounts		$ 33,300	$ 5,799
Subsequent Event
Subsequent Event [Line Items]
Number of common stock shares newly issued	16,100,000
Public offering price of the shares sold	$ 3
Proceeds from public offering, net of underwriters' discounts	$ 45,100