Aptinyx (APTX) 10-Q 18 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 15, 2023
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-38535
Entity Registrant Name	Aptinyx Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4626057
Entity Address, Address Line One	909 Davis Street
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Evanston
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60201
City Area Code	847
Local Phone Number	871-0377
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	APTX
Security Exchange Name	NASDAQ
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		67,715,718
Entity Central Index Key	0001674365
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 44,573	$ 56,205
Short-term restricted cash	179	179
Prepaid expenses and other current assets	3,005	7,646
Total current assets	47,757	64,030
Other assets	206	2,622
Property and equipment, net		32
Total assets	47,963	66,684
Current liabilities:
Accounts payable	1,374	724
Accrued expenses and other current liabilities	1,157	2,772
Finance lease, current	1,138
Term loan, current	5,654	2,795
Total current liabilities	9,323	6,291
Finance lease, non-current	940
Term loan, non-current	19,444	22,108
Total liabilities	29,707	28,399
Commitments and contingencies (see Note 12)
Stockholders' equity:
Preferred stock, $0.01 par value, 10,000 shares authorized and no shares issued and outstanding as of March 31, 2023 and December 31, 2022
Common stock, $0.01 par value, 150,000 shares authorized as of March 31, 2023 and December 31, 2022, 67,716 issued and outstanding as of March 31, 2023 and December 31, 2022	677	677
Additional paid-in capital	391,381	390,344
Accumulated deficit	(373,802)	(352,736)
Total stockholders' equity	18,256	38,285
Total liabilities and stockholders' equity	$ 47,963	$ 66,684

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2023	Dec. 31, 2022
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	67,716	67,716
Common stock, shares outstanding	67,716	67,716

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating expenses:
Research and development	$ 16,093	$ 13,602
General and administrative	4,229	5,777
Total operating expenses	20,322	19,379
Loss from operations	(20,322)	(19,379)
Other (income) expense, net	(286)	(29)
Interest expense	1,030	477
Net loss and comprehensive loss	$ (21,066)	$ (19,827)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.31)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.31)	$ (0.29)
Weighted-average number of common shares outstanding, basic (in shares)	67,716	67,716
Weighted-average number of common shares outstanding, diluted (in shares)	67,716	67,716

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (21,066)	$ (19,827)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	32	38
Change in fair value of derivative liability associated with contingently issuable warrants		15
Non-cash interest expense related to term loan	196	139
Impairment of assets related to supply manufacturing agreements	8,199
Stock-based compensation expense	1,037	2,350
Changes in operating assets and liabilities:
Prepaid expenses and other assets	1,202	2,375
Accounts payable	664	1,075
Accrued expenses and other liabilities	(1,629)	(2,089)
Net cash used in operating activities	(11,365)	(15,924)
Cash flows from financing activities:
Repayment of principal portion of finance lease	(265)
Proceeds from issuance of term loan, net of issuance costs paid to lender		10,000
Payment of debt issuance costs	(2)	(13)
Payment of offering costs		(27)
Net cash provided by financing activities	(267)	9,960
Net decrease in cash, cash equivalents and restricted cash	(11,632)	(5,964)
Cash, cash equivalents and restricted cash, at beginning of period	56,384	106,321
Cash, cash equivalents and restricted cash, at end of period	44,752	100,357
Supplemental disclosure of cash flow information:
Cash paid for interest	822	298
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use asset recognized in exchange for finance lease obligations	$ 2,344
Deferred offering costs not yet paid		95
Debt issuance costs not yet paid		2
Issuance of warrants in connection with term loan financing		$ 206

Statements of Stockholders' Equ

Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common stock	Additional paid-in capital	Accumulated deficit	Total
Stockholders' (deficit) equity beginning balance at Dec. 31, 2021	$ 677	$ 381,966	$ (287,887)	$ 94,756
Stockholders' (deficit) equity shares beginning balance at Dec. 31, 2021	67,716
Stockholders' (Deficit) Equity Rollforward
Issuance of warrants in connection with term loan financing		206		206
Stock-based compensation		2,350		2,350
Net loss			(19,827)	(19,827)
Stockholders' (deficit) equity ending balance at Mar. 31, 2022	$ 677	384,522	(307,714)	77,485
Stockholders' (deficit) equity shares ending balance at Mar. 31, 2022	67,716
Stockholders' (deficit) equity beginning balance at Dec. 31, 2022	$ 677	390,344	(352,736)	$ 38,285
Stockholders' (deficit) equity shares beginning balance at Dec. 31, 2022	67,716			67,716
Stockholders' (Deficit) Equity Rollforward
Stock-based compensation		1,037		$ 1,037
Net loss			(21,066)	(21,066)
Stockholders' (deficit) equity ending balance at Mar. 31, 2023	$ 677	$ 391,381	$ (373,802)	$ 18,256
Stockholders' (deficit) equity shares ending balance at Mar. 31, 2023	67,716			67,716

Organization

Organization	3 Months Ended
	Mar. 31, 2023
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 nervous system disorders. Liquidity, capital resources, and going concern The financial statements are prepared in accordance with generally accepted accounting principles applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has incurred operating losses and negative cash flows from operations since inception. As of March 31, 2023, the Company had an accumulated deficit of $373.8 million, cash and cash equivalents of $44.6 million, and total liabilities of $29.7 million. In February 2023, in light of its financial condition and the results of recent clinical studies that did not support continued development, the Company began implementation of a strategic restructuring plan to preserve capital and reduce operating costs. eliminated 60% of its workforce, leaving a core team of individuals to lead the strategic alternatives review process. On May 4, 2023, following the completion of the review of strategic alternatives, the Company’s board unanimously approved a plan of liquidation and dissolution of the Company, which plan is subject to stockholder approval. ​ These conditions and events raise substantial doubt about the Company’s ability to continue as a going concern. ​ The Company does not have plans to alleviate the substantial doubt about the Company’s ability to continue as a going concern. ​ The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Summary of significant accounti

Summary of significant accounting policies	3 Months Ended
	Mar. 31, 2023
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, 2022 (the “Annual Report”) filed with the SEC on March 30, 2023. 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 plans and expectations for the plan of liquidation and dissolution, Significant accounting policies The Company’s significant accounting policies are described herein and 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 three months ended March 31, 2023.

Supplemental financial informat

Supplemental financial information	3 Months Ended
	Mar. 31, 2023
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 (in thousands). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Cash and cash equivalents ​ $ 44,573 ​ $ 56,205 ​ Short-term restricted cash ​ 179 ​ 179 ​ Total cash, cash equivalents, and restricted cash shown in the statements of cash flows ​ $ 44,752 ​ $ 56,384 ​ ​ Prepaid expenses and other current assets ​ Prepaid expenses and other current assets consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Prepaid clinical $ 2,048 ​ $ 3,828 Prepaid insurance ​ ​ 579 ​ ​ 1,109 ​ Prepaid manufacturing costs ​ ​ — ​ ​ 2,380 ​ Other prepaid expenses and current assets 378 ​ 329 Total prepaid expenses and other current assets $ 3,005 ​ $ 7,646 ​ Accrued expenses and other current liabilities ​ Accrued expenses and other current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Employee-related expenses ​ $ 256 ​ $ 1,724 ​ Development costs and sponsored research ​ 151 ​ 84 ​ Clinical trials ​ — ​ 184 ​ Other ​ 750 ​ 780 ​ Total accrued expenses and other current liabilities ​ $ 1,157 ​ $ 2,772 ​ ​

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2023
Fair value measurements
Fair value measurements	4. Fair value measurements ASC 820, Fair Value Measurement ● 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 and liabilities measured at fair value on a recurring basis as of March 31, 2023, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ ​ ​ ​ ​ ​ ​ 2023 Level 1 Level 2 Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds, included in cash and cash equivalents ​ $ 42,071 ​ $ 42,071 ​ $ — ​ $ — Money market funds, included in restricted cash ​ ​ 179 ​ ​ 179 ​ — ​ — Total Assets ​ $ 42,250 ​ $ 42,250 ​ $ — ​ $ — ​ Assets measured at fair value on a recurring basis as of December 31, 2022, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ 2022 Level 1 Level 2 Level 3 Assets ​ ​ ​ ​ Money market funds, included in cash and cash equivalents ​ $ 55,686 ​ $ 55,686 ​ $ — ​ $ — Money market funds, included in restricted cash ​ ​ 179 ​ ​ 179 ​ — ​ — Total Assets ​ $ 55,865 ​ $ 55,865 ​ $ — ​ $ — ​

Property and equipment

Property and equipment	3 Months Ended
	Mar. 31, 2023
Property and equipment
Property and equipment	​ 5. Property and equipment, net Property and equipment are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 2022 Office equipment and furniture ​ 152 ​ 152 ​ Laboratory equipment ​ — ​ 401 ​ Leasehold improvements ​ 979 ​ 979 ​ Less accumulated depreciation ​ (1,131) ​ (1,500) ​ Property and equipment, net ​ $ — ​ $ 32 ​ ​ Depreciation expense was less than $0.1 million for each of the three months ended March 31, 2023 and 2022. The Company disposed of certain laboratory equipment that were fully depreciated at the time of disposal.

Debt

Debt	3 Months Ended
	Mar. 31, 2023
Debt
Debt	6. Debt On September 15, 2021, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with K2 HealthVentures LLC (the “Lender”). The Lender agreed to make available to the Company term loans in an aggregate principal amount of up to $50.0 million under the Loan Agreement. The Company planned to use the proceeds of the term loans to support clinical development as well as for working capital and general corporate purposes. The Loan Agreement provided a term loan commitment of $50.0 million in four potential tranches: (i) a $15.0 million term loan facility funded on September 15, 2021 (the “First Tranche Term Loan”); (ii) a $10.0 million term loan facility (the “Second Tranche Term Loan”) funded on March 14, 2022; (iii) a $10.0 million term loan facility (the “Third Tranche Term Loan”) available at the Company’s option between July 1, 2022, and December 1, 2022, subject to the draw of the Second Tranche Term Loan and positive Phase 2 clinical data from NYX-2925 or NYX-458 and progression of another clinical asset; and (iv) a $15.0 million term loan facility (the “Fourth Tranche Term Loan”) available through July 1, 2023, at the Company’s option but subject to review of financial and clinical plans and Lender’s Investment Committee approval. All four of these term loans had a maturity date of September 1, 2025. Borrowings under all four term loan facilities bore interest at a floating per annum rate equal to the greater of (i) 7.95% and (ii) the Prime Rate plus 4.70% . The Company was permitted to make interest-only payments on the First Tranche Term Loan for the first 24 months following the funding date. The interest-only period could be extended by an additional 12 months , subject to the funding of the Second Tranche Term Loan and the funding of the Third Tranche Term Loan. The term of the combined facility would have been 48 months , with repayment in monthly installments commencing at the end of the resulting interest-only period as outlined above through the end of the 48-month term. The Company was obligated to pay a final fee equal to 6.45% of the aggregate amount of the term loans funded (“Exit Fee”), to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans. The Company had the option to prepay all, but not less than all, of the outstanding principal balance of the term loans under the Loan Agreement. If the Company prepaid all of the term loans prior to the maturity date, it would pay the Lender a prepayment penalty fee based on a percentage of the outstanding principal balance, equal to 3% if the payment occurred on or before 24 months after the initial funding date, 2% if the prepayment occurred more than 24 months after, but on or before 36 months after the initial funding date, or 1% if the prepayment occurred more than 36 months after the initial funding date. The Company also is obligated to pay the Lender an origination fee of 0.8% of all term loans funded at the time of funding. The Lender could, at its option, elect to convert any portion of no more than $4 million of the then outstanding term loan amount and all accrued and unpaid interest thereon into shares of the Company’s common stock at a conversion price of the lesser of $4.25 per share and the price per share of the common stock in the Company’s next equity offering in which the Company receives at least $20.0 million of gross proceeds . The Company determined that the embedded conversion option is not required to be separated from the term loan. The embedded conversion option meets the derivative accounting scope exception since the embedded conversion option is indexed to the Company’s own common stock and qualifies for classification within stockholders’ equity. The Company’s obligations under the Loan Agreement were secured by a first priority security interest in substantially all of its assets. The Loan Agreement contained customary representations and warranties, and also includes customary events of default, including payment default, breach of covenants, change of control, and material adverse effects. The Loan Agreement restricted certain activities, such as disposing of the Company’s business or certain assets, incurring additional debt or liens or making payments on other debt, making certain investments and declaring dividends, acquiring or merging with another entity, engaging in transactions with affiliates or encumbering intellectual property, among others. There were no financial covenants associated with the Loan Agreement. The Company was in compliance with all non-financial covenants under the Loan Agreement as of March 31, 2023. Upon the occurrence of an event of default, a default interest rate of an additional 5% per annum could have been applied to the outstanding loan balances, and the Lender may declare all outstanding obligations immediately due and payable and exercise all of its rights and remedies as set forth in the Loan Agreement and under applicable law. On April 21, 2023, the Company completed voluntary prepayment under the Loan Agreement, and the Loan Agreement and all other documents entered into in connection with the Loan Agreement were terminated, as described in Note 12. The Company recorded interest expense related to the Loan Agreement of $1.0 million and $0.5 million for the three months ended March 31, 2023 and 2022, respectively. Future principal debt payments of the term loans funded as of March 31, 2023, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ 2023 ​ $ 2,782 2024 ​ 12,048 2025 ​ 10,170 2026 ​ — Total principal payments ​ 25,000 Exit Fee ​ ​ 1,613 Total principal payments and Exit Fee ​ ​ 26,613 Less: Unamortized debt discount related to warrants ​ ​ (300) Less: Unamortized debt discount related to Exit Fee ​ ​ (954) Less: Unamortized debt issuance costs ​ (261) Term loan, net ​ ​ 25,098 Less: current portion of term loan ​ ​ (5,654) Term loan, non-current ​ $ 19,444 ​

Stock incentive plan

Stock incentive plan	3 Months Ended
	Mar. 31, 2023
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. 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 months ended March 31, 2023 and 2022, was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ ​ ​ March 31, ​ ​ 2023 2022 Research and development ​ $ 165 ​ $ 375 ​ General and administrative ​ 872 ​ 1,975 ​ Total stock‑based compensation expense ​ $ 1,037 ​ $ 2,350 ​ ​ 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, 2022 11,836 ​ $ 4.96 7.31 ​ $ — Granted 2,533 ​ 0.36 ​ Exercised ​ — ​ ​ — ​ ​ ​ ​ ​ Forfeited and canceled (1,061) ​ 2.09 ​ Outstanding, March 31, 2023 ​ 13,308 ​ $ 4.31 ​ 7.10 ​ $ — Vested and expected to vest at March 31, 2023 ​ 13,308 ​ $ 4.31 ​ 7.10 ​ $ — Exercisable at March 31, 2023 8,002 ​ $ 5.87 5.90 ​ $ — ​ During the three months ended March 31, 2023 and 2022, the Company granted 2.5 million and 1.7 million stock options, respectively, and these options had a weighted-average grant-date fair value of $0.29 and $2.74 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 three months ended March 31, 2023, were similar to those as described in the Annual Report, except for the manner in which the expected volatility was determined. The expected volatility for the Company’s options granted during the three months ended March 31, 2023, is based on a weighted-average of the historical volatility of share values of publicly traded companies within the biotechnology industry, which includes the historical volatility of the Company’s stock since the Company’s initial public offering. As of March 31, 2023, there was $7.7 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.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2023
Warrants
Warrants	8. Warrants ​ Warrants ​ On September 15, 2021, the Company entered into the Loan Agreement with the Lender pursuant to which the Lender may provide the Company with term loans in an aggregate principal amount of up to $50.0 million. ​ On September 15, 2021, in connection with the funding of the First Tranche Term Loan, the Company issued a warrant exercisable for 147,600 shares of the Company’s common stock at an exercise price of $2.29 per share. The warrant is immediately exercisable for 147,600 shares and expires on September 15, 2031. ​ On March 14, 2022, in connection with the funding of the Second Tranche Term Loan, the Company issued a warrant exercisable for 98,399 shares of the Company’s common stock at an exercise price of $2.29 per share. The warrant is immediately exercisable for 98,399 shares and expires on September 15, 2031. ​ No warrants had been exercised as of March 31, 2023. Any shares of the Company’s common stock issued upon exercise of the warrants are permitted to be settled in unregistered shares. The warrants are classified as equity as they meet all of the conditions under GAAP for equity classification. The Company has calculated the fair value of the warrants for initial measurement and date of funding of the Second Tranche Term Loan, and reassesses whether equity classification for the warrants is appropriate upon any changes to the warrants or capital structure, at each balance sheet date. ​ The Company determined that the fair value of the warrants issued in connection with the First Tranche Term Loan and Second Tranche Term Loan was $0.3 million and $0.2 million, respectively. The specific assumptions used to determine the initial measurement of fair value of the warrants were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First Tranche ​ Second Tranche ​ ​ Term Loan ​ Term Loan ​ ​ ​ ​ ​ ​ ​ Expected volatility 95 % ​ 93 % Expected dividends None ​ ​ None ​ Expected term 5.00 Years ​ ​ 5.00 Years ​ Risk-free rate 0.81 % ​ 2.10 % ​

Net loss per share

Net loss per share	3 Months Ended
	Mar. 31, 2023
Net loss per share
Net loss per share	9. Net loss per share Basic and diluted net loss per share attributable to common stockholders was calculated as follows for the three months ended March 31, 2023 and 2022 (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ ​ ​ March 31, ​ ​ 2023 2022 Numerator: ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (21,066) ​ $ (19,827) ​ Denominator: ​ ​ ​ ​ Weighted-average common shares outstanding—basic and diluted ​ 67,716 ​ 67,716 ​ Net loss per share attributable to common stockholders—basic and diluted ​ $ (0.31) ​ $ (0.29) ​ ​ The following common stock equivalents outstanding as of March 31, 2023 and 2022, 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 ​ ​ March 31, ​ 2023 2022 Stock options issued and outstanding 13,308 12,428 Warrants ​ 246 ​ 246 Total 13,554 12,674 ​

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2023
Income taxes
Income taxes	10. 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 March 31, 2023, and December 31, 2022. ​ ​

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and contingencies
Commitments and contingencies	11. 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 March 31, 2023. 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 as of March 31, 2023. The Company does not anticipate recognizing any significant losses relating to these arrangements. Operating 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 the related right of use lease asset and lease liability on the Company’s balance sheets. In 2021, the Company entered into an agreement with a contract manufacturing organization for manufacturing of materials for research and development purposes, including manufacturing of clinical trial materials. This agreement is valid for a period of five years , unless terminated earlier by the Company. The Company has determined that the agreement includes an embedded lease. There are no contractual minimum purchase obligations associated with this agreement. All payments associated with this agreement are variable. Total rent expense under all the operating lease agreements amounted to $0.3 million and $0.2 million for the three months ended March 31, 2023 and 2022, respectively. Finance lease On January 1, 2023, a clinical supply manufacturing agreement commenced with a minimum order commitment of $2.6 million and a minimum lease term of two years.

Restructuring and Impairment Ch

Restructuring and Impairment Charges	3 Months Ended
	Mar. 31, 2023
Restructuring and Impairment Charges
Restructuring and impairment charges	12. Restructuring and impairment charges Employee termination benefits Employees affected by the reduction in workforce (footnote 1) received involuntary termination benefits that provided a one-time benefit arrangement and have no requirements to provide future service. Costs associated with the reduction in workforce amounted to $1.4 million for the three months ended March 31, 2023 of which $1.3 million were recognized within research and development and $0.1 million were recognized within general and administrative in the condensed statement of operations. Impairment of long-lived clinical supply manufacturing prepayments The Company determined that its inability to advance its development programs indicated impairment on its clinical supply manufacturing prepayments and right of use assets in the amount of $8.2 million for the three months ended March 31, 2023, and recognized within research and development in the condensed statement of operations. ​

Subsequent events

Subsequent events	3 Months Ended
	Mar. 31, 2023
Subsequent events
Subsequent Event	13. Subsequent events ​ Debt prepayment ​ On April 21, 2023, the Company completed voluntary prepayment of all outstanding principal, accrued and unpaid interest, fees, costs and expenses, equal to $27.5 million in the aggregate under the Loan and Security Agreement dated as of September 15, 2021. Upon receipt by the Lender, all obligations, covenants, debts and liabilities of the Company under the Loan Agreement were satisfied and discharged in full, and the Loan Agreement and all other documents entered into in connection with the Loan Agreement were terminated. ​ Dissolution ​ On May 4, 2023, following the conclusion of the Company's review of strategic alternatives, the Company's Board of Directors unanimously approved the dissolution and liquidation of the Company pursuant to a plan of complete liquidation and dissolution, which plan is subject to stockholder approval.

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2023
Summary of significant accounting policies
Basis of presentation	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, 2022 (the “Annual Report”) filed with the SEC on March 30, 2023. 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	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 plans and expectations for the plan of liquidation and dissolution,

Supplemental financial inform_2

Supplemental financial information (Tables)	3 Months Ended
	Mar. 31, 2023
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 (in thousands). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Cash and cash equivalents ​ $ 44,573 ​ $ 56,205 ​ Short-term restricted cash ​ 179 ​ 179 ​ Total cash, cash equivalents, and restricted cash shown in the statements of cash flows ​ $ 44,752 ​ $ 56,384 ​ ​
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Prepaid clinical $ 2,048 ​ $ 3,828 Prepaid insurance ​ ​ 579 ​ ​ 1,109 ​ Prepaid manufacturing costs ​ ​ — ​ ​ 2,380 ​ Other prepaid expenses and current assets 378 ​ 329 Total prepaid expenses and other current assets $ 3,005 ​ $ 7,646 ​
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 2022 Employee-related expenses ​ $ 256 ​ $ 1,724 ​ Development costs and sponsored research ​ 151 ​ 84 ​ Clinical trials ​ — ​ 184 ​ Other ​ 750 ​ 780 ​ Total accrued expenses and other current liabilities ​ $ 1,157 ​ $ 2,772 ​

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair value measurements
Schedule of assets and liabilities measured at fair value	Assets and liabilities measured at fair value on a recurring basis as of March 31, 2023, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ ​ ​ ​ ​ ​ ​ 2023 Level 1 Level 2 Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds, included in cash and cash equivalents ​ $ 42,071 ​ $ 42,071 ​ $ — ​ $ — Money market funds, included in restricted cash ​ ​ 179 ​ ​ 179 ​ — ​ — Total Assets ​ $ 42,250 ​ $ 42,250 ​ $ — ​ $ — ​ Assets measured at fair value on a recurring basis as of December 31, 2022, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ 2022 Level 1 Level 2 Level 3 Assets ​ ​ ​ ​ Money market funds, included in cash and cash equivalents ​ $ 55,686 ​ $ 55,686 ​ $ — ​ $ — Money market funds, included in restricted cash ​ ​ 179 ​ ​ 179 ​ — ​ — Total Assets ​ $ 55,865 ​ $ 55,865 ​ $ — ​ $ —

Property and equipment (Tables)

Property and equipment (Tables)	3 Months Ended
	Mar. 31, 2023
Property and equipment
Schedule of property and equipment, net	Property and equipment are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 2022 Office equipment and furniture ​ 152 ​ 152 ​ Laboratory equipment ​ — ​ 401 ​ Leasehold improvements ​ 979 ​ 979 ​ Less accumulated depreciation ​ (1,131) ​ (1,500) ​ Property and equipment, net ​ $ — ​ $ 32 ​ ​

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2023
Debt
Schedule of maturities of long-term debt	Future principal debt payments of the term loans funded as of March 31, 2023, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ 2023 ​ $ 2,782 2024 ​ 12,048 2025 ​ 10,170 2026 ​ — Total principal payments ​ 25,000 Exit Fee ​ ​ 1,613 Total principal payments and Exit Fee ​ ​ 26,613 Less: Unamortized debt discount related to warrants ​ ​ (300) Less: Unamortized debt discount related to Exit Fee ​ ​ (954) Less: Unamortized debt issuance costs ​ (261) Term loan, net ​ ​ 25,098 Less: current portion of term loan ​ ​ (5,654) Term loan, non-current ​ $ 19,444

Stock incentive plan (Tables)

Stock incentive plan (Tables)	3 Months Ended
	Mar. 31, 2023
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 months ended March 31, 2023 and 2022, was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ ​ ​ March 31, ​ ​ 2023 2022 Research and development ​ $ 165 ​ $ 375 ​ General and administrative ​ 872 ​ 1,975 ​ Total stock‑based compensation expense ​ $ 1,037 ​ $ 2,350 ​ ​
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, 2022 11,836 ​ $ 4.96 7.31 ​ $ — Granted 2,533 ​ 0.36 ​ Exercised ​ — ​ ​ — ​ ​ ​ ​ ​ Forfeited and canceled (1,061) ​ 2.09 ​ Outstanding, March 31, 2023 ​ 13,308 ​ $ 4.31 ​ 7.10 ​ $ — Vested and expected to vest at March 31, 2023 ​ 13,308 ​ $ 4.31 ​ 7.10 ​ $ — Exercisable at March 31, 2023 8,002 ​ $ 5.87 5.90 ​ $ — ​

Warrants (Tables)

Warrants (Tables)	3 Months Ended
	Mar. 31, 2023
Loan agreement
Class of Warrant or Right [Line Items]
Schedule of fair value of the warrants or rights	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First Tranche ​ Second Tranche ​ ​ Term Loan ​ Term Loan ​ ​ ​ ​ ​ ​ ​ Expected volatility 95 % ​ 93 % Expected dividends None ​ ​ None ​ Expected term 5.00 Years ​ ​ 5.00 Years ​ Risk-free rate 0.81 % ​ 2.10 %

Net loss per share (Tables)

Net loss per share (Tables)	3 Months Ended
	Mar. 31, 2023
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 months ended March 31, 2023 and 2022 (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ ​ ​ March 31, ​ ​ 2023 2022 Numerator: ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders ​ $ (21,066) ​ $ (19,827) ​ Denominator: ​ ​ ​ ​ Weighted-average common shares outstanding—basic and diluted ​ 67,716 ​ 67,716 ​ Net loss per share attributable to common stockholders—basic and diluted ​ $ (0.31) ​ $ (0.29) ​ ​
Schedule of anti-dilutive securities excluded from computation of diluted net loss per share	The following common stock equivalents outstanding as of March 31, 2023 and 2022, 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 ​ ​ March 31, ​ 2023 2022 Stock options issued and outstanding 13,308 12,428 Warrants ​ 246 ​ 246 Total 13,554 12,674

Organization (Details)

Organization (Details) - USD ($) $ in Thousands	1 Months Ended
	Feb. 28, 2023	Mar. 31, 2023	Dec. 31, 2022
Organization
Accumulated deficit		$ (373,802)	$ (352,736)
Cash and cash equivalents		44,573	56,205
Total liabilities		$ 29,707	$ 28,399
Employee Severance | Separation of Workforce
Organization
Percentage of eliminating workforce	60%

Supplemental financial inform_3

Supplemental financial information - Cash, cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Supplemental financial information
Cash and cash equivalents	$ 44,573	$ 56,205
Short-term restricted cash	179	179
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 44,752	$ 56,384	$ 100,357	$ 106,321

Supplemental financial inform_4

Supplemental financial information - Prepaid expenses and other current assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Supplemental financial information
Prepaid clinical	$ 2,048	$ 3,828
Prepaid insurance	579	1,109
Prepaid manufacturing costs		2,380
Other prepaid expenses and current assets	378	329
Total prepaid expenses and other current assets	$ 3,005	$ 7,646

Supplemental financial inform_5

Supplemental financial information - Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Supplemental financial information
Employee-related expenses	$ 256	$ 1,724
Development costs and sponsored research	151	84
Clinical trials		184
Other	750	780
Total accrued expenses and other current liabilities	$ 1,157	$ 2,772

Fair value measurements (Detail

Fair value measurements (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair value measurements
Total Assets	$ 42,250	$ 55,865
Money market funds, included in cash and cash equivalents
Fair value measurements
Money market funds	42,071	55,686
Money market funds, included in restricted cash
Fair value measurements
Money market funds	179	179
Level 1
Fair value measurements
Total Assets	42,250	55,865
Level 1 | Money market funds, included in cash and cash equivalents
Fair value measurements
Money market funds	42,071	55,686
Level 1 | Money market funds, included in restricted cash
Fair value measurements
Money market funds	$ 179	$ 179

Property and equipment (Details

Property and equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Property and equipment
Less accumulated depreciation	$ (1,131)		$ (1,500)
Property and equipment, net			32
Maximum
Property and equipment
Depreciation	100	$ 100
Office equipment and furniture
Property and equipment
Property and equipment, gross	152		152
Laboratory equipment
Property and equipment
Property and equipment, gross			401
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 979		$ 979

Debt (Details)

Debt (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Mar. 14, 2022 USD ($)	Sep. 15, 2021 USD ($) tranche $ / shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of term loan				$ 10,000
Interest expense			$ 1,030	477
Loan agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 50,000
Number of tranches | tranche		4
Interest rate		7.95%
Term of debt		48 months
Final fee percentage		6.45%
Origination fee		0.80%
Conversion price | $ / shares		$ 4.25
Equity offering proceeds threshold to set debt conversion price		$ 20,000
Additional default interest rate		5%
Interest expense			$ 1,000	$ 500
Loan agreement | Minimum
Debt Instrument [Line Items]
Threshold amount for conversion		$ 4,000
Loan agreement | Prepayment occurs on or before 24 months after initial funding
Debt Instrument [Line Items]
Prepayment penalty percentage		3%
Threshold period in which prepayment occurs		24 months
Loan agreement | Prepayment occurs more than 24 months and on or before 36 months after initial funding
Debt Instrument [Line Items]
Prepayment penalty percentage		2%
Loan agreement | Prepayment occurs more than 24 months and on or before 36 months after initial funding | Minimum
Debt Instrument [Line Items]
Threshold period in which prepayment occurs		24 months
Loan agreement | Prepayment occurs more than 24 months and on or before 36 months after initial funding | Maximum
Debt Instrument [Line Items]
Threshold period in which prepayment occurs		36 months
Loan agreement | Prepayment occurs more than 36 months after initial funding
Debt Instrument [Line Items]
Prepayment penalty percentage		1%
Threshold period in which prepayment occurs		36 months
Loan agreement | Prime
Debt Instrument [Line Items]
Spread (as a percent)		4.70%
First Tranche Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of term loan		$ 15,000
Period for which interest only payment is permitted		24 months
Additional period for which interest only payment can be extended		12 months
Second Tranche Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of term loan	$ 10,000
Third Tranche Term Loan Facility
Debt Instrument [Line Items]
Principal amount		$ 10,000
Third Tranche Term Loan For 15 Million [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 15,000

Debt - Future Principal Debt Pa

Debt - Future Principal Debt Payments on The Loan Payable (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Future Principal Debt Payments
2023	$ 2,782
2024	12,048
2025	10,170
Total principal payments	25,000
Exit Fee	1,613
Total principal payments and Exit Fee	26,613
Less: Unamortized debt discount related to warrants	(300)
Less: Unamortized debt discount related to Exit Fee	(954)
Less: Unamortized debt issuance costs	(261)
Term loan, net	25,098
Less: current portion of term loan	(5,654)	$ (2,795)
Term loan, non-current	$ 19,444	$ 22,108

Stock incentive plan - Stock-ba

Stock incentive plan - Stock-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,037	$ 2,350
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	165	375
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 872	$ 1,975

Stock incentive plan - Activity

Stock incentive plan - Activity related to stock options (Details) - Stock options - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Shares
Outstanding, at the beginning of the period	11,836
Granted	2,533	1,700
Forfeited and canceled	(1,061)
Outstanding, at the end of the period	13,308		11,836
Vested and expected to vest	13,308
Exercisable	8,002
Weighted-average exercise price
Outstanding, at the beginning of the period	$ 4.96
Granted	0.36
Forfeited and canceled	2.09
Outstanding, at the end of the period	4.31		$ 4.96
Vested and expected to vest	4.31
Exercisable at the end of the period	$ 5.87
Weighted-average remaining contractual term
Weighted-average remaining contractual term	7 years 1 month 6 days		7 years 3 months 21 days
Vested and expected to vest	7 years 1 month 6 days
Exercisable	5 years 10 months 24 days
Weighted-average grant date fair value per share	$ 0.29	$ 2.74
Unrecognized stock-based compensation related to non-vested stock options	$ 7.7
Expenses recognized over a weighted-average period (in years)	2 years 3 months 18 days
Term of award	10 years
Vesting period	4 years

Warrants (Details)

Warrants (Details)	3 Months Ended
	Mar. 31, 2023 shares	Mar. 14, 2022 USD ($) $ / shares shares	Sep. 15, 2021 USD ($) $ / shares shares
Class of Warrant or Right [Line Items]
Warrants exercised | shares	0
Loan agreement
Class of Warrant or Right [Line Items]
Maximum borrowing capacity			$ 50,000,000
First Tranche Term Loan
Class of Warrant or Right [Line Items]
Issued warrant exercisable | shares			147,600
Exercise price | $ / shares			$ 2.29
Derivative liability, included in other long-term liabilities			$ 300,000
First Tranche Term Loan | Expected volatility
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input			95
First Tranche Term Loan | Expected dividends
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input			0
First Tranche Term Loan | Expected term
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input			5
First Tranche Term Loan | Risk-free rate
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input			0.81
Second Tranche Term Loan
Class of Warrant or Right [Line Items]
Issued warrant exercisable | shares		98,399
Exercise price | $ / shares		$ 2.29
Derivative liability, included in other long-term liabilities		$ 200,000
Second Tranche Term Loan | Expected volatility
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input		93
Second Tranche Term Loan | Expected dividends
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input		0
Second Tranche Term Loan | Expected term
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input		5
Second Tranche Term Loan | Risk-free rate
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input		2.10

Net loss per share (Details)

Net loss per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss attributable to common stockholders	$ (21,066)	$ (19,827)
Denominator:
Weighted-average number of common shares outstanding, basic (in shares)	67,716	67,716
Weighted-average number of common shares outstanding, diluted (in shares)	67,716	67,716
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.31)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.31)	$ (0.29)

Net loss per share - Anti-dilut

Net loss per share - Anti-dilutive securities (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
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	13,554	12,674
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	13,308	12,428
Warrants.
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	246	246

Commitments and contingencies (

Commitments and contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Jan. 01, 2023	Dec. 31, 2021
Commitments and contingencies
Lease term				5 years
Lease payments	$ 0.3	$ 0.2
Purchase obligation			$ 2.6
Finance lease, lease term			2 years

Restructuring and Impairment _2

Restructuring and Impairment Charges (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Restructuring Cost and Reserve [Line Items]
Impairment of assets related to supply manufacturing agreements	$ 8,199
Employee Severance | Separation of Workforce
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	1,400
Employee Severance | Separation of Workforce | Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	1,300
Employee Severance | Separation of Workforce | General and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 100

Subsequent events (Details)

Subsequent events (Details) $ in Millions	Apr. 24, 2023 USD ($)
Subsequent events. | Loan agreement
Subsequent Event [Line Items]
Repayments of Debt	$ 27.5