Werewolf Therapeutics (HOWL) 10-Q 11 May 23 2023 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2023	May 05, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-40366
Entity Registrant Name	WEREWOLF THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-3523180
Entity Address, Address Line One	200 Talcott Ave
Entity Address, Address Line Two	2nd Floor
Entity Address, City or Town	Watertown
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02472
City Area Code	617
Local Phone Number	952‑0555(Former name, former address and former fiscal year, if changed since last report)
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	HOWL
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	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,611,355
Entity Central Index Key	0001785530
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 147,868	$ 129,315
Prepaid expenses and other current assets	2,439	3,957
Other receivables	6,255	6,928
Total current assets	156,562	140,200
Property and equipment, net	8,699	8,988
Restricted cash and cash equivalents	21,011	1,214
Operating lease right of use asset	8,127	8,463
Other non-current assets	670	1,380
Total assets	195,069	160,245
Current liabilities:
Accounts payable	2,106	1,221
Accrued expenses and other current liabilities	13,321	14,152
Operating lease liability, current	2,146	2,084
Deferred revenue, current	4,149	6,532
Total current liabilities	21,722	23,989
Operating lease liability, net of current portion	12,043	12,600
Deferred revenue, net of current portion	1,168	1,128
Notes payable, net of discount and issuance costs	39,063	0
Other liabilities	0	191
Total liabilities	73,996	37,908
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value, 5,000 shares authorized at March 31, 2023 and December 31, 2022; no shares issued or outstanding as of March 31, 2023 or December 31, 2022	0	0
Common stock, $0.0001 par value, 200,000 shares authorized as of March 31, 2023 and December 31, 2022; 35,339 and 31,515 shares issued as of March 31, 2023 and December 31, 2022, respectively; 35,301 and 31,434 shares outstanding as of March 31, 2023 and December 31, 2022, respectively	3	3
Additional paid-in capital	439,757	429,039
Accumulated deficit	(318,687)	(306,705)
Total stockholders’ equity	121,073	122,337
Total liabilities and stockholders’ equity	$ 195,069	$ 160,245

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock authorized (shares)	5,000,000
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Common stock par value (usd per share)	$ 0.0001	$ 0.0001
Common stock authorized (shares)	200,000,000
Common stock issued (shares)	35,339,000	31,515,000
Common stock outstanding (shares)	35,301,000	31,434,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue:
Collaboration revenue	$ 4,464	$ 0
Operating expenses:
Research and development	11,706	10,945
General and administrative	4,981	4,421
Total operating expenses	16,687	15,366
Operating loss	(12,223)	(15,366)
Other income:
Other expense, net	(1,106)	(16)
Interest income, net	1,347	39
Total other income	241	23
Net loss	$ (11,982)	$ (15,343)
Net loss per share attributable to common stockholders, basic and diluted
Net (loss) per share attributable to common stockholders, basic (usd per share)	$ (0.34)	$ (0.56)
Net (loss) per share attributable to common stockholders, diluted (usd per share)	$ (0.34)	$ (0.56)
Weighted-average common shares outstanding, basic and diluted
Weighted average common shares outstanding, basic (shares)	34,785	27,393
Weighted average common shares outstanding, diluted (shares)	34,785	27,393

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ (Deficit) Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Stockholders' equity, beginning balance (shares) at Dec. 31, 2021		27,608,000
Stockholders' equity, beginning balance at Dec. 31, 2021	$ 152,787	$ 2	$ 405,680	$ (252,895)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	1,745		1,745
Exercise of common stock options (shares)		46,000
Stock option exercises	129		129
Net income (loss)	(15,343)			(15,343)
Stockholders' equity, ending balance (shares) at Mar. 31, 2022		27,654,000
Stockholders' equity, ending balance at Mar. 31, 2022	139,318	$ 2	407,554	(268,238)
Stockholders' equity, beginning balance (shares) at Dec. 31, 2022		31,515,000
Stockholders' equity, beginning balance at Dec. 31, 2022	122,337	$ 3	429,039	(306,705)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from at the market offering, net of issuance costs (shares)		3,824,000
Issuance of common stock from at the market offering, net of issuance costs	8,610		8,610
Stock-based compensation expense	$ 2,108		2,108
Exercise of common stock options (shares)	0
Net income (loss)	$ (11,982)			(11,982)
Stockholders' equity, ending balance (shares) at Mar. 31, 2023		35,339,000
Stockholders' equity, ending balance at Mar. 31, 2023	$ 121,073	$ 3	$ 439,757	$ (318,687)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ (Deficit) Equity (unaudited) (Parentheticals) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 103

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities:
Net income (loss)	$ (11,982)	$ (15,343)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,108	1,745
Depreciation expense	425	98
Non-cash interest expense	13	0
Non-cash lease expense	336	383
Change in fair value of success payment liability	(1,021)	0
Amortization of debt issuance costs	60	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,443	1,789
Other receivables	673	0
Other non-current assets	(18)	0
Accounts payable	961	(674)
Accrued expenses and other current liabilities	133	(2,031)
Deferred revenue	(2,343)	0
Right of use assets and operating lease liability	(495)	82
Other liabilities	(191)	0
Net cash used in operating activities	(9,898)	(13,951)
Investing activities:
Purchases of property and equipment	(168)	(28)
Net cash used in investing activities	(168)	(28)
Financing activities:
Proceeds from at the market offering of common stock	8,713	0
Proceeds from drawdown of term loans	40,000	0
Payment of equity issuance costs	(90)	0
Proceeds from stock option exercises	0	159
Net cash provided by financing activities	48,623	159
Net increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents	38,557	(13,820)
Cash, cash equivalents and restricted cash and cash equivalents—beginning of period	130,529	158,830
Cash, cash equivalents and restricted cash and cash equivalents—end of period	169,086	145,010
Non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accrued expenses	79	1,552
Issuance costs in accounts payable and accrued expenses	17	0
Stock option exercise receivables in prepaid expenses and other current assets	$ 0	$ (30)

Description of Business, Organi

Description of Business, Organization, and Liquidity	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Organization, and Liquidity	Nature of Business Werewolf Therapeutics, Inc. (“Werewolf” or the “Company”) was incorporated in the state of Delaware in October 2017. The Company is an innovative biopharmaceutical company pioneering the development of therapeutics engineered to stimulate the body’s immune system for the treatment of cancer. The Company’s headquarters are located in Watertown, Massachusetts. Since inception, the Company has devoted substantially all of its time and efforts to performing research and development activities, raising capital and recruiting management and technical staff to support these operations. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, technical risks associated with the successful research, development and manufacturing of product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Current and future programs will require significant research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The Company had cash and cash equivalents of $147.9 million at March 31, 2023. The Company expects that its cash and cash equivalents will enable it to fund its operating expenses and capital expenditure requirements for at least twelve months from the filing date of this Quarterly Report. However, additional funding will be necessary beyond this point to fund future preclinical and clinical activities. The Company expects to finance its future cash needs through a combination of equity or debt financings, collaboration agreements, strategic alliances and licensing arrangements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements as of March 31, 2023 and December 31, 2022, and for the three months ended March 31, 2023 and 2022, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 filed with the SEC (the “Annual Report”). The information presented in the condensed consolidated financial statements and related notes as of March 31, 2023, and for the three months ended March 31, 2023 and 2022, is unaudited. The December 31, 2022 condensed consolidated balance sheet included herein was derived from the audited financial statements as of that date, but does not include all disclosures, including notes, required by GAAP for complete financial statements. Interim results for the three months ended March 31, 2023 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2023, or any future period. The accompanying condensed consolidated financial statements include the accounts of Werewolf Therapeutics, Inc. and its wholly-owned subsidiary, Werewolf Therapeutics Mass Securities, Inc. All intercompany transactions and balances have been eliminated in consolidation. Summary of Significant Accounting Policies The significant accounting policies and estimates used in the preparation of the condensed consolidated financial statements are described in the Company’s audited financial statements as of and for the year ended December 31, 2022, and the notes thereto, which are included in the Annual Report. There have been no material changes in the Company’s significant accounting policies during the three months ended March 31, 2023. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates which include, but are not limited to, the fair values of common stock and the fair value of the success payment liability. Actual results could differ from those estimates. Recent Accounting Pronouncements Accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.

Jazz Collaboration Agreement

Jazz Collaboration Agreement	3 Months Ended
	Mar. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Jazz Collaboration Agreement	Jazz Collaboration and License Agreement In April 2022, the Company entered into an exclusive global collaboration and license agreement (the “Collaboration Agreement”) with Jazz Pharmaceuticals Ireland Limited (“Jazz”) pursuant to which the Company granted Jazz certain licenses to develop and commercialize products containing the Company’s Interferon alpha (“IFNα”) INDUKINE™ molecule, JZP898 (formerly WTX-613), as well as products containing certain isolated recombinant polypeptides comprising IFNα that meet specified criteria (each such product, a “Licensed Product”). Under the Collaboration Agreement, the Company is responsible for certain pre-clinical development activities with respect to JZP898 (formerly WTX-613) and other development activities specified in mutually agreed upon development plans. Jazz will generally reimburse the Company for the cost of such activities. Jazz will be responsible for all other development and commercialization activities conducted to exploit the Licensed Products, including submission of an investigational new drug application (“IND”) to the U.S. Food and Drug Administration (the “FDA”). Under the terms of the Collaboration Agreement, the Company received a non-refundable upfront cash payment of $15.0 million in April 2022. Milestones and Royalties The Company is eligible to receive up to $520.0 million in development and regulatory milestones, and up to $740.0 million in sales-based milestones for all Licensed Products. In addition, the Company is eligible to receive tiered mid-single digit royalties based on Jazz’s, and any of its affiliates’ and sublicensees’ annual net sales of Licensed Products, subject to reduction in specified circumstances. Accounting Analysis under ASC 606 Identification of the Contract(s) The Company assessed the Collaboration Agreement and concluded that it represents a contract with a customer within the scope of ASC Topic 606, Revenue from Contracts with Customers . Identification of Promises and Performance Obligations The Company has concluded that the exclusive license to its intellectual property, JZP898 (formerly WTX-613), and the non-exclusive corresponding “know-how” are not capable of being distinct from the other promises within the contract, and as such, the Company has determined that the license and “know-how” combined with the other research and development services and supply represent a single combined performance obligation. Determination of Transaction Price The overall transaction price as of the inception of the contract was determined to be $32.3 million, which is comprised of the nonrefundable upfront payment of $15.0 million and the estimated costs for research services of $17.3 million. Outside of the estimated costs for research services, there is no other variable consideration included in the transaction price at inception. The Company used the most likely amount method to estimate variable consideration and estimated that the most likely amount for each potential development and regulatory milestone payment under this agreement is zero, as achievement of those milestones is uncertain and highly susceptible to factors outside the Company’s control. Accordingly, all such milestone payments were excluded from the transaction price. Management will reevaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, will adjust the transaction price as necessary. Sales based royalties, including milestones based on the level of sales, were also excluded from the transaction price, as the license is deemed to be the predominant item to which the royalties relate. The Company will recognize such revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The upfront payment of $15.0 million was recorded as deferred revenue and, along with payments related to the Company’s conduct of research services under the Collaboration Agreement, will be recognized as revenue over approximately 3.7 years using an input-based measurement of actual costs incurred as a percentage of the estimated total costs expected to be incurred over the expected term of conduct of the research services. The Company believes this input-based method to recognize revenue best reflects the transfer of value to Jazz. Recognition of Revenue For the three months ended March 31, 2023, using the cost-to-cost input method, which best depicts the research services performed for the customer, the Company recognized $4.5 million of revenue related to the Collaboration Agreement. As of March 31, 2023, there is $4.1 million and $1.2 million of current and long-term deferred revenue, respectively, related to the Collaboration Agreement. All costs associated with the Collaboration Agreement are recorded in research and development expense in the condensed consolidated statements of operations. “Unbilled receivables” of $1.8 million and $4.1 million was included within “Other receivables” in the accompanying condensed consolidated balance sheets as of March 31, 2023 and December 31, 2022, respectively. The following table presents changes in the Company’s contract liabilities during the three months ended March 31, 2023 (in thousands): Balance as of Balance as of December 31, 2022 Additions Reductions March 31, 2023 Contract liabilities: Deferred revenue $ 7,660 $ — $ (2,343) $ 5,317 Totals $ 7,660 $ — $ (2,343) $ 5,317 As of March 31, 2023, the Company had not received any milestone or royalty payments under the Collaboration Agreement.

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	Financial Instruments and Fair Value Measurements Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value is determined based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect certain market assumptions. As a basis for considering such assumptions, GAAP establishes a three-tier value hierarchy, which prioritizes the inputs used to develop the assumptions and for measuring fair value as follows: (Level 1) observable inputs such as quoted prices in active markets for identical assets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The Company’s financial instruments that are measured at fair value on a recurring basis consist of money market funds, classified as cash, cash equivalents and restricted cash and cash equivalents on the Company’s condensed consolidated balance sheets, and a success payment liability pursuant to an amended and restated loan and security agreement (the “Loan Agreement”) with Pacific Western Bank (“PWB”) (see Note 7, Term Loan ). The Company measures the fair value of money market funds based on quoted prices in active markets for identical securities. The carrying amounts reflected in the condensed consolidated balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values, due to their short-term nature. Assets and liabilities measured at fair value on a recurring basis as of March 31, 2023 were as follows (in thousands): Quoted Price in Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Money market funds $ 167,379 $ — $ — $ 167,379 Total assets $ 167,379 $ — $ — $ 167,379 Liabilities Success payment liability $ — $ — $ 1,591 $ 1,591 Total liabilities $ — $ — $ 1,591 $ 1,591 The success payment liability was included within “Accrued expenses and other current liabilities” in the accompanying condensed consolidated balance sheets as of March 31, 2023 and December 31, 2022. Assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 were as follows (in thousands): Quoted Price in Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Money market funds $ 128,812 $ — $ — $ 128,812 Total assets $ 128,812 $ — $ — $ 128,812 Liabilities Success payment liability $ — $ — $ 570 $ 570 Total liabilities $ — $ — $ 570 $ 570 There were no changes in valuation techniques during the three months ended March 31, 2023. Success Payment Liability The Company is obligated to pay to PWB a one-time success payment upon the occurrence of the Company achieving certain conditions defined in the Loan Agreement. The maximum aggregate success payment that could be payable by the Company is $1.6 million. The following table reconciles the change in fair value of the success payment liability during the three months ended March 31, 2023 based on Level 3 inputs (in thousands): Three Months Ended Balance at December 31, 2022 $ 570 Additions — Change in fair value 1,021 Balance at March 31, 2023 $ 1,591 The success payment liability is stated at fair value and is considered Level 3 because its fair value measurement is based, in part, on significant inputs not observed in the market. The Company models the value of the liability based on several key variables, including probability of event occurrence and timing of event occurrence. The fair value of the success payment liability was determined using a probability weighted expected return method, in which the probability and timing of potential future events is considered in order to estimate the fair value of the success payment liability as of each valuation date. Management determined the fair value of the success payment liability as of March 31, 2023 using the following significant unobservable inputs: March 31, 2023 Probability of Success Fee Event 100 % Expected term (in years) 0.1 Discount rate 6.9 % Significant increases (decreases) in these inputs could result in a significantly lower or higher fair value measurement. The Company remeasured the liability at fair value with a corresponding increase of $1.0 million recorded to other expense, net for the three months ended March 31, 2023.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2023
Cash and Cash Equivalents [Abstract]
Restricted Cash	Restricted Cash and Cash Equivalents The Company maintained restricted cash and cash equivalents of $21.2 million and $1.2 million at March 31, 2023 and December 31, 2022, respectively. At March 31, 2023, $20.0 million of the restricted cash and cash equivalents balance represents an obligation under the term loan facility for the required minimum cash balance in PWB accounts. This became effective upon imminent achievement of the funding goal as required by the terms of the Loan Agreement (see Note 7, Term Loan ). The remaining restricted cash amounts are comprised solely of letters of credit required pursuant to the Company’s leased office spaces. At March 31, 2023, $0.2 million of the Company’s restricted cash balance was included within “Prepaid expenses and other current assets” in the accompanying condensed consolidated balance sheets. Three Months Ended March 31, 2023 Three Months Ended March 31, 2022 (in thousands) Beginning of Period End of Period Beginning of Period End of Period Cash and cash equivalents $ 129,315 $ 147,868 $ 157,531 $ 143,711 Restricted cash and cash equivalents, current — 207 91 91 Restricted cash and cash equivalents, non-current 1,214 21,011 1,208 1,208 Cash, cash equivalents and restricted cash and cash equivalents $ 130,529 $ 169,086 $ 158,830 $ 145,010

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities as of March 31, 2023 and December 31, 2022 were comprised as follows (in thousands): March 31, December 31, Manufacturing $ 6,402 $ 6,674 Contract research 2,466 2,990 Employee compensation and benefits 1,400 3,135 Professional fees 816 613 Success payment liability 1,591 570 Other 646 170 Total accrued expenses and other current liabilities $ 13,321 $ 14,152

Term Loan

Term Loan	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Term Loan	Term Loan In April 2022, the Company entered into the Loan Agreement with PWB. Under the terms of the Loan Agreement, PWB made available a term loan in an aggregate principal amount of up to $20.0 million (“Tranche I Loan”) available at any time after the closing date until February 28, 2024 as extended to August 31, 2024 upon the satisfaction of certain conditions set forth in the Loan Agreement (such date, the “Amortization Date”). Based on the satisfaction of certain conditions defined in the Loan Agreement, PWB was also obligated to make available an additional term loan in the aggregate principal amount of up to $20.0 million (“Tranche II Loan”, or collectively with the Tranche I Loan, the “Term Loans”) available at any time after the closing date until the Amortization Date upon the acceptance by the U.S. Food and Drug Administration (the “FDA”) of two investigational new drug (“IND”) submissions on or before March 31, 2023. As of March 31, 2023, the Company has drawn down $40.0 million of the Term Loans. The outstanding notes payable balance under the Term Loans as of March 31, 2023 consists of the following (in thousands): March 31, 2023 Principal $ 40,000 Unamortized debt discount and issuance costs (937) Net carrying amount $ 39,063 Subsequent to the interest-only period which ends on August 31, 2024, the Company is required to make equal monthly principal payments plus interest until the Term Loans mature on August 31, 2026. The Term Loans will bear interest on the outstanding daily balance at a floating annual rate equal to greater of: (i) 0.5% above the prime rate then in effect or (ii) 4.5%. If the prime rate changes throughout the term, the interest rate will be adjusted effective on the date of the prime rate change. All interest chargeable under the Loan Agreement is computed on a 360-day year for the actual number of days elapsed, with interest payable monthly. The Company recognized interest expense related to the Loan Agreement of $0.2 million during the three months ended March 31, 2023. The Company did not incur interest expense during the three months ended March 31, 2022. The Company is obligated to pay PWB a fee in the event of certain corporate transactions equal to either (i) the greater of (a) $0.2 million and (b) 2.0% of the amount drawn under the Term Loans, for a transaction occurring on or before March 31, 2023, or (ii) for any transaction occurring thereafter, the greater of (a) $0.4 million and (b) 4.0% of the amount drawn under the Term Loans (the “Success Fee”). The Success Fee will survive ten years from the date of payment of the Term Loans in full, such that, if the Loan Agreement is terminated prior to the payment of the Success Fee the Company will remain obligated to pay the Success Fee upon the occurrence of a Success Fee Event (as defined in the Loan Agreement) during such ten-year period. The Company determined that the Success Fee constitutes a freestanding financial instrument and should be accounted for as a liability in connection with ASC 815, Derivatives and Hedging . The Company determined that the fair value of the Success Fee upon the closing date of the Loan Agreement and then marked to market the fair value of the Success Fee as of March 31, 2023. All outstanding obligations under the Loan Agreement are secured by the Company’s personal property (exclusive of any intellectual property) and are subject to acceleration in the event of default. In the event of a late payment or default, the Company is obligated to pay a fee equal to 5.0% of such unpaid amounts. In connection with the Loan Agreement, the Company is required to comply with certain negative covenants, which among other things, restrict the Company from (i) incurring future debt or granting liens, (ii) effectuating a merger or consolidation with or into any other business organization, (iii) paying dividends or making certain other distributions, (iv) selling or otherwise transferring its assets, (v) making investments in any entities or instruments other than certain investments specified in the Loan Agreement and (vi) making capitalized expenditures in excess of 125% of the amount provided for in the annual budget approved by the board of directors. The Loan Agreement also contains standard affirmative covenants, including with respect to the issuance of audited consolidated financial statements, insurance, and maintenance of good standing and government compliance in the Company’s state of formation. On or before September 30, 2023, the Company was required to raise aggregate gross cash process of at least $50.0 million from the sale or issuance of the Company’s equity or from strategic partnerships or any similar transaction. From after receipt of those proceeds, the Company would be required to maintain at all times at least $20.0 million of otherwise unrestricted cash in accounts with PWB, included within “Restricted cash and cash equivalents” on our Balance Sheets. On April 17, 2023, the Company achieved the $50.0 million funding milestone, triggering the corresponding $20.0 million cash covenant, full payment of the Success Fee of $1.6 million, and the updated Amortization Date of August 31, 2024. PWB has the right to accelerate all outstanding obligations of the Company under the Loan Agreement or terminate any remaining Term Loan commitments in the event of a material adverse effect on (i) the operations, business or financial condition of the Company, (ii) the Company’s ability to repay any portion of the Term Loans or perform any of its other obligations under the Loan Agreement, and (iii) the Company’s interest in, or the value, perfection or priority of PWB’s security interest in the collateral. As of March 31, 2023, the Company had drawn both Term Loans and had $40.0 million outstanding principal.

Common and Preferred Stock

Common and Preferred Stock	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Common and Preferred Stock	Common and Preferred Stock Common Stock The Company is authorized to issue 200.0 million shares of common stock. Common stockholders are entitled to dividends if and when declared by the Company’s board of directors. As of March 31, 2023, no dividends on common stock had been declared by the Company. On May 10, 2022, the Company entered into a Sales Agreement (the “Sales Agreement”) with SVB Securities LLC (“SVB”), 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 (the “ATM Offering”). The Sales Agreement provides that SVB 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. As of March 31, 2023, the Company had sold an aggregate of 7,651,816 shares under the ATM Offering at an average price of $3.35 per share for net proceeds of $24.3 million after deducting sales commissions and offering expenses. Preferred Stock The Company is authorized to issue 5.0 million shares of undesignated preferred stock in one or more series. As of March 31, 2023, no shares of preferred stock were issued or outstanding. Shares Reserved for Future Issuance The Company had reserved shares of common stock for issuance as of March 31, 2023 and December 31, 2022 as follows (in thousands): As of March 31, As of December 31, 2023 2022 Shares reserved for exercises of outstanding stock options 6,665 5,244 Shares reserved for vesting of restricted stock units 323 323 Shares reserved for exercises of warrants 59 59 Shares reserved for future issuance under the 2021 Stock Incentive Plan 1,094 939 Total shares reserved for future issuance 8,141 6,565

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation 2017 Stock Incentive Plan In December 2017, the Company adopted the 2017 Stock Incentive Plan (the “2017 Plan”), as amended and restated, under which it could grant incentive stock options (“ISOs”), non-qualified stock options, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), stock appreciation rights and other stock-based awards to eligible employees, officers, directors and consultants. The terms of stock options and RSAs, including vesting requirements, are determined by the board of directors, subject to the provisions of the 2017 Plan. 2021 Stock Incentive Plan In April 2021, the board of directors adopted and the Company’s stockholders approved the 2021 Stock Incentive Plan (the “2021 Plan”), which became effective immediately prior to the effectiveness of the Company’s initial public offering (“IPO”). As a result of the adoption of the 2021 Plan, no further awards will be made under the 2017 Plan. The 2021 Plan provides for the grant of ISOs, non-qualified stock options, RSAs, RSUs, stock appreciation rights and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors are eligible to receive awards under the 2021 Plan. The terms of awards, including vesting requirements, are determined by the board of directors, subject to the provisions of the 2021 Plan. The Company initially registered 3,352,725 shares of common stock under the 2021 Plan, pursuant to a Registration Statement on Form S-8 filed with the SEC on April 30, 2021, which was comprised of (i) 2,843,116 shares of common stock reserved for issuance under the 2021 Plan, (ii) 31,884 shares of common stock originally reserved for issuance under the 2017 Plan that became available for issuance under the 2021 Plan upon the completion of the IPO, and (iii) 477,725 shares of unvested restricted stock subject to repurchase by the Company that may become issuable under the 2021 Plan following such repurchase. The 2021 Plan also provides that an additional number of shares will be added annually to the shares authorized for issuance under the 2021 Plan on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2022 and continuing until, and including, the fiscal year ended December 31, 2031. The number of shares added each year will be equal to the lesser of (i) 5% of the number of outstanding common stock on such date and (ii) such amount as determined by the board of directors. Effective January 1, 2022 and 2023, 1,380,397 and 1,575,753 additional shares, respectively, were automatically added to the shares reserved for issuance under the 2021 Plan pursuant to this evergreen provision. As of March 31, 2023, there were 1,093,993 shares available for future issuance under the 2021 Plan. 2021 Employee Stock Purchase Plan In April 2021, the board of directors adopted and the Company’s stockholders approved the 2021 Employee Stock Purchase Plan (the “2021 ESPP”), which became effective immediately prior to the effectiveness of the IPO. The Company initially reserved 244,000 shares of common stock for future issuance under the 2021 ESPP. The 2021 ESPP provides that an additional number of shares will automatically be added to the shares reserved for issuance on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2022 and continuing for each fiscal year until, and including, the fiscal year ending on December 31, 2032. The number of shares added each year will be equal to the lowest of (i) 488,000 shares of common stock, (ii) 1% of the number of shares of outstanding common stock on such date, and (iii) such amount as determined by the board of directors. Effective January 1, 2023, 315,150 additional shares were automatically added to the shares reserved for issuance under the 2021 ESPP pursuant to the evergreen provision. The Company initiated its first offering period under the 2021 ESPP in December 2022. The 2021 ESPP provides that eligible employees may contribute up to 15% of their eligible earnings toward the semi-annual purchase of the Company’s common stock. The 2021 ESPP is qualified under Section 423 of the Internal Revenue Code. The employee’s purchase price is derived from a formula based on the closing price of the common stock on the first day of the offering period versus the closing price on the last date of purchase (or, if not a trading day, on the immediately preceding trading day). The offering period under the 2021 ESPP has a duration of six months, and the purchase price with respect to each offering period beginning on or after such date is, until otherwise amended, equal to 85% of the lesser of (i) the fair market value of the Company’s common stock at the commencement of the applicable six-month offering period or (ii) the fair market value of the Company’s common stock on the purchase date. The Company estimate the fair value of the common stock under the 2021 ESPP using a Black-Scholes valuation model. The fair value was estimate on the date of grant using the Black-Scholes option valuation model and the straight-line attribution approach with the following assumptions: risk-free interest rate (4.7%); expected term (0.5 years); expected volatility (77.0%); and an expected dividend yield (—%). The Company recorded less than $0.1 million of stock-based compensation under the 2021 ESPP for the three months ended March 31, 2023. As of March 31, 2023, there was unrecognized stock-based compensation expense of less than $0.1 million related to the current ESPP offering period, which ends May 31, 2023. Stock-Based Compensation Expense Total stock-based compensation expense recognized in the condensed consolidated statements of operations for the three months ended March 31, 2023 and 2022 was as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 1,020 $ 781 General and administrative 1,088 964 Total stock-based compensation $ 2,108 $ 1,745 RSA Activity The Company may, at its discretion, repurchase unvested shares of restricted stock issued pursuant to the 2017 Plan at the initial purchase price if the employees or non-employees terminate their service relationship with the Company. The following table summarizes RSA activity during the three months ended March 31, 2023 (in thousands, except per share amounts): Shares/Units Weighted-Average Unvested at December 31, 2022 81 $ 1.38 Granted — $ — Vested (43) $ 1.37 Forfeited — $ — Unvested at March 31, 2023 38 $ 1.38 As of March 31, 2023, there was unrecognized stock-based compensation expense related to unvested RSAs of less than $0.1 million, which the Company expects to recognize over a weighted-average period of approximately 0.2 years. The aggregate fair value of RSAs that vested during the three months ended March 31, 2023 and 2022, based upon the fair values of the stock underlying the RSAs on the day of vesting, was $0.1 million and $0.5 million, respectively. RSU Activity The Company has also granted RSUs to its employees under the 2021 Plan. The following table summarizes RSU activity during the three months ended March 31, 2023 (in thousands, except per share amounts): Shares/Units Weighted-Average Unvested at December 31, 2022 323 $ 4.32 Granted — $ — Vested — $ — Forfeited — $ — Unvested at March 31, 2023 323 $ 4.32 As of March 31, 2023, there was unrecognized stock-based compensation expense related to unvested RSUs of $0.8 million, which the Company expects to recognize over a weighted-average period of approximately 1.0 year. No RSUs vested during the three months ended March 31, 2023 or 2022. Stock Option Activity During the three months ended September 30, 2022, the Company granted performance-based stock options to certain executive officers for the purchase of an aggregate of 883,352 shares of common stock with a grant date fair value of $3.36 per share. These stock options vest only upon achievement of specified performance targets related to certain business objectives. As of March 31, 2023, none of these options were vested because none of the specified performance targets had been achieved. Because achievement of the specified performance targets was not deemed probable as of September 30, 2022, the Company did not record any expense for these stock options from the date of issuance through March 31, 2023. The fair value of stock options granted during the three months ended March 31, 2023 and 2022 was calculated on the date of grant using the following weighted-average assumptions: Three Months Ended 2023 2022 Risk-free interest rate 3.9 % 1.6 % Expected term (in years) 6.0 6.0 Dividend yield — % — % Expected volatility 82.6 % 76.0 % Using the Black-Scholes option pricing model, the weighted-average grant date fair value of stock options granted during the three months ended March 31, 2023 and 2022 was $1.48 and $7.54 per share, respectively. The following table summarizes stock option activity during the three months ended March 31, 2023 (in thousands, except per share amounts): Options Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Outstanding at December 31, 2022 5,244 $ 7.86 8.34 Granted 1,429 $ 2.05 Exercised — $ — Cancelled (8) $ 15.45 Outstanding at March 31, 2023 6,665 $ 6.60 8.61 Exercisable at March 31, 2023 2,011 $ 7.87 7.96 There were no stock option exercises during the three months ended March 31, 2023. The aggregate intrinsic fair value of stock options exercised during the three months ended March 31, 2022 was $0.3 million. As of March 31, 2023, there was unrecognized stock-based compensation expense related to unvested stock options of $18.6 million, which the Company expects to recognize over a weighted-average period of approximately 2.1 years.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2023
Related Party Transactions [Abstract]
Related Parties	Related Parties In May 2022, the Company entered into a sublease agreement with Crossbow Therapeutics, Inc. (“Crossbow”), for which entities affiliated with MPM Capital (“MPM Capital”) are also beneficial owners, to sublease the entirety of its office and laboratory space in Cambridge, Massachusetts. Luke Evnin, Ph.D., the chair of the Company’s board of directors, co-founded MPM Capital and serves as Managing Director of MPM Capital. Briggs Morrison, who serves on the Company’s board of directors, serves as Executive Partner of MPM Capital and Chief Executive Officer of Crossbow. The term of the sublease agreement commenced in June 2022 and ends in March 2024, with no option to extend. The Company received cash payments under its sublease of approximately $0.4 million during the three months ended March 31, 2023. In addition, the Company received $0.2 million from Crossbow in June 2022 as a security deposit that is included within “Accrued expenses and other current liabilities” in the accompanying condensed consolidated balance sheets as of March 31, 2023.

Net Loss Attributable to Common

Net Loss Attributable to Common Stockholders per Share	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Loss Attributable to Common Stockholders per Share	Net Loss Attributable to Common Stockholders per ShareFor purposes of the diluted net loss attributable to common stockholders per share calculation, outstanding stock options, unvested RSAs, unvested RSUs and warrants to purchase common stock are considered to be potentially dilutive securities, however the following weighted- average amounts were excluded from the calculation of diluted net loss attributable to common stockholders per share because their effect would be anti-dilutive (in thousands): March 31, 2023 2022 Outstanding stock options 6,665 4,133 Unvested RSAs 38 234 Unvested RSUs 323 — Warrants to purchase common stock 59 59 Total 7,085 4,426

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsIn April 2023, the Success Fee Event occurred and, as such, the Company was obligated to pay the corresponding Success Fee to PWB, in accordance with the terms of the Loan Agreement. The Company removed the corresponding financial instrument for the success fee liability and paid the total $1.6 million upon occurrence of the Success Fee Event. Upon occurrence of the Success Fee Event, the Amortization Date was extended to August 31, 2024, thereby extending the due date for all unpaid principal and accrued and unpaid interest with respect to the Term Loans to August 31, 2026.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements as of March 31, 2023 and December 31, 2022, and for the three months ended March 31, 2023 and 2022, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 filed with the SEC (the “Annual Report”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates which include, but are not limited to, the fair values of common stock and the fair value of the success payment liability. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.
Subsequent Events	Subsequent EventsThe Company has evaluated subsequent events and transactions that occurred in the period from the balance sheet date to the date that the financial statements were issued.

Jazz Collaboration Agreement (T

Jazz Collaboration Agreement (Tables)	3 Months Ended
	Mar. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Contract with Customer, Contract Asset, Contract Liability, and Receivable	The following table presents changes in the Company’s contract liabilities during the three months ended March 31, 2023 (in thousands): Balance as of Balance as of December 31, 2022 Additions Reductions March 31, 2023 Contract liabilities: Deferred revenue $ 7,660 $ — $ (2,343) $ 5,317 Totals $ 7,660 $ — $ (2,343) $ 5,317

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis as of March 31, 2023 were as follows (in thousands): Quoted Price in Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Money market funds $ 167,379 $ — $ — $ 167,379 Total assets $ 167,379 $ — $ — $ 167,379 Liabilities Success payment liability $ — $ — $ 1,591 $ 1,591 Total liabilities $ — $ — $ 1,591 $ 1,591 The success payment liability was included within “Accrued expenses and other current liabilities” in the accompanying condensed consolidated balance sheets as of March 31, 2023 and December 31, 2022. Assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 were as follows (in thousands): Quoted Price in Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Money market funds $ 128,812 $ — $ — $ 128,812 Total assets $ 128,812 $ — $ — $ 128,812 Liabilities Success payment liability $ — $ — $ 570 $ 570 Total liabilities $ — $ — $ 570 $ 570
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table reconciles the change in fair value of the success payment liability during the three months ended March 31, 2023 based on Level 3 inputs (in thousands): Three Months Ended Balance at December 31, 2022 $ 570 Additions — Change in fair value 1,021 Balance at March 31, 2023 $ 1,591
Fair Value, Liabilities Measured on Recurring Basis	Management determined the fair value of the success payment liability as of March 31, 2023 using the following significant unobservable inputs: March 31, 2023 Probability of Success Fee Event 100 % Expected term (in years) 0.1 Discount rate 6.9 %

Restricted Cash (Tables)

Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2023
Cash and Cash Equivalents [Abstract]
Restrictions on Cash and Cash Equivalents	At March 31, 2023, $0.2 million of the Company’s restricted cash balance was included within “Prepaid expenses and other current assets” in the accompanying condensed consolidated balance sheets. Three Months Ended March 31, 2023 Three Months Ended March 31, 2022 (in thousands) Beginning of Period End of Period Beginning of Period End of Period Cash and cash equivalents $ 129,315 $ 147,868 $ 157,531 $ 143,711 Restricted cash and cash equivalents, current — 207 91 91 Restricted cash and cash equivalents, non-current 1,214 21,011 1,208 1,208 Cash, cash equivalents and restricted cash and cash equivalents $ 130,529 $ 169,086 $ 158,830 $ 145,010

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses	Accrued expenses and other current liabilities as of March 31, 2023 and December 31, 2022 were comprised as follows (in thousands): March 31, December 31, Manufacturing $ 6,402 $ 6,674 Contract research 2,466 2,990 Employee compensation and benefits 1,400 3,135 Professional fees 816 613 Success payment liability 1,591 570 Other 646 170 Total accrued expenses and other current liabilities $ 13,321 $ 14,152

Common and Preferred Stock (Tab

Common and Preferred Stock (Tables)	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Schedule of Common Stock Reserved for Issuance	The Company had reserved shares of common stock for issuance as of March 31, 2023 and December 31, 2022 as follows (in thousands): As of March 31, As of December 31, 2023 2022 Shares reserved for exercises of outstanding stock options 6,665 5,244 Shares reserved for vesting of restricted stock units 323 323 Shares reserved for exercises of warrants 59 59 Shares reserved for future issuance under the 2021 Stock Incentive Plan 1,094 939 Total shares reserved for future issuance 8,141 6,565

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation Expense Recognized	Total stock-based compensation expense recognized in the condensed consolidated statements of operations for the three months ended March 31, 2023 and 2022 was as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 1,020 $ 781 General and administrative 1,088 964 Total stock-based compensation $ 2,108 $ 1,745
Restricted Stock Awards Activity	The following table summarizes RSA activity during the three months ended March 31, 2023 (in thousands, except per share amounts): Shares/Units Weighted-Average Unvested at December 31, 2022 81 $ 1.38 Granted — $ — Vested (43) $ 1.37 Forfeited — $ — Unvested at March 31, 2023 38 $ 1.38 Shares/Units Weighted-Average Unvested at December 31, 2022 323 $ 4.32 Granted — $ — Vested — $ — Forfeited — $ — Unvested at March 31, 2023 323 $ 4.32
Weighted -average Valuation Assumptions	The fair value of stock options granted during the three months ended March 31, 2023 and 2022 was calculated on the date of grant using the following weighted-average assumptions: Three Months Ended 2023 2022 Risk-free interest rate 3.9 % 1.6 % Expected term (in years) 6.0 6.0 Dividend yield — % — % Expected volatility 82.6 % 76.0 %
Summary of Stock Option Activity	The following table summarizes stock option activity during the three months ended March 31, 2023 (in thousands, except per share amounts): Options Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Outstanding at December 31, 2022 5,244 $ 7.86 8.34 Granted 1,429 $ 2.05 Exercised — $ — Cancelled (8) $ 15.45 Outstanding at March 31, 2023 6,665 $ 6.60 8.61 Exercisable at March 31, 2023 2,011 $ 7.87 7.96

Net (Loss) Income Attributable

Net (Loss) Income Attributable to Common Stockholders per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of (Loss) Income per Share	For purposes of the diluted net loss attributable to common stockholders per share calculation, outstanding stock options, unvested RSAs, unvested RSUs and warrants to purchase common stock are considered to be potentially dilutive securities, however the following weighted- average amounts were excluded from the calculation of diluted net loss attributable to common stockholders per share because their effect would be anti-dilutive (in thousands): March 31, 2023 2022 Outstanding stock options 6,665 4,133 Unvested RSAs 38 234 Unvested RSUs 323 — Warrants to purchase common stock 59 59 Total 7,085 4,426

Description of Business, Orga_2

Description of Business, Organization, and Liquidity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 147,868	$ 129,315	$ 143,711	$ 157,531

Jazz Collaboration Agreement -

Jazz Collaboration Agreement - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Collaboration revenue		$ 4,464	$ 0
Research and development		11,706	$ 10,945
Deferred revenue, current		4,149		$ 6,532
Deferred revenue, net of current portion		1,168		1,128
Unbilled receivables		$ 1,800		$ 4,100
Jazz Collaboration Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable upfront cash payment received	$ 15,000
Development and regulatory milestones (up to)	520,000
Sales-Based Milestones (up to)	740,000
Transaction price	32,300
Estimated future reimbursable costs	$ 17,300
Collaboration agreement, term	3 years 8 months 12 days

Jazz Collaboration Agreement _2

Jazz Collaboration Agreement - Contract with Customer, Contract Asset, Contract Liability, and Receivable (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Contract liabilities:
Deferred revenue, beginning balance	$ 7,660
Additions	0
Reductions	(2,343)
Deferred revenue, ending balance	$ 5,317

Financial Instruments and Fai_3

Financial Instruments and Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Success payment liability	$ 1,591	$ 570
Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	167,379	128,812
Success payment liability	1,591	570
Total liabilities	1,591	570
Money market funds | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	167,379	128,812
Quoted Price in Active Markets (Level 1) | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	167,379	128,812
Success payment liability	0	0
Total liabilities	0	0
Quoted Price in Active Markets (Level 1) | Money market funds | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	167,379	128,812
Significant Other Observable Inputs (Level 2) | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	0	0
Success payment liability	0	0
Total liabilities	0	0
Significant Other Observable Inputs (Level 2) | Money market funds | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	0	0
Significant Unobservable Inputs (Level 3) | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	0	0
Success payment liability	1,591	570
Total liabilities	1,591	570
Significant Unobservable Inputs (Level 3) | Money market funds | Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	$ 0	$ 0

Financial Instruments and Fai_4

Financial Instruments and Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Success payment liability	$ 1,591	$ 570
Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Success payment liability	1,591	570
Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Success payment liability	1,591	$ 570
Change in fair value	1,021
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Success payment liability	$ 1,600

Financial Instruments and Fai_5

Financial Instruments and Fair Value Measurements - Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Recurring $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contract liabilities, beginning balance	$ 570
Contract liabilities, ending balance	1,591
Significant Unobservable Inputs (Level 3)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contract liabilities, beginning balance	570
Additions	0
Change in fair value	1,021
Contract liabilities, ending balance	$ 1,591

Financial Instruments and Fai_6

Financial Instruments and Fair Value Measurements - Unobservable Inputs (Details) - Recurring	Mar. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Probability of Success Fee Event	1
Discount rate	0.069
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected term (in years)	1 month 6 days

Restricted Cash - Narrative (De

Restricted Cash - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Non-current restricted cash	$ 21,200	$ 1,200
Restricted cash included in "Prepaid expenses and other current assets"	207	$ 0	$ 91	$ 91
Term Loans | Term loan
Restricted Cash and Cash Equivalents Items [Line Items]
Non-current restricted cash	$ 20,000

Restricted Cash - Summary of Re

Restricted Cash - Summary of Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 147,868	$ 129,315	$ 143,711	$ 157,531
Restricted cash and cash equivalents, current	207	0	91	91
Restricted cash and cash equivalents, non-current	21,011	1,214	1,208	1,208
Cash, cash equivalents and restricted cash and cash equivalents	$ 169,086	$ 130,529	$ 145,010	$ 158,830

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Manufacturing	$ 6,402	$ 6,674
Employee compensation and benefits	1,400	3,135
Professional fees	816	613
Contract research	2,466	2,990
Success payment liability	1,591	570
Other	646	170
Accrued expenses and other current liabilities	$ 13,321	$ 14,152

Term Loan (Details)

Term Loan (Details) - USD ($)		1 Months Ended		3 Months Ended
	Apr. 17, 2023	May 05, 2023	Apr. 30, 2022	Mar. 31, 2023	Mar. 31, 2022
Debt Instrument [Line Items]
Floating rate spread in effect (greater than) (percent)			4.50%
Proceeds from at the market offering of common stock				$ 8,713,000	$ 0
Debt instrument, conditional fee, liability				1,600,000
Subsequent Event
Debt Instrument [Line Items]
Success fee liability paid	$ 1,600,000	$ 1,600,000
Prime Rate
Debt Instrument [Line Items]
Floating rate spread in effect (greater than) (percent)			0.50%
Term loan | Period One
Debt Instrument [Line Items]
Delayed draw fee			$ 200,000
Success Fee (percent)			2%
Term loan | Period Two
Debt Instrument [Line Items]
Delayed draw fee			$ 400,000
Success Fee (percent)			4%
Term loan | Tranche I Loan
Debt Instrument [Line Items]
Term loan available			$ 20,000,000
Term loan | Tranche II Loan
Debt Instrument [Line Items]
Term loan available			$ 20,000,000
Term loan | Term Loans
Debt Instrument [Line Items]
Drawings on Term Loans				40,000,000
Outstanding borrowings				40,000,000
Default payment fee (percent)			5%
Maximum annual capital expenditures			1.25
Proceeds from at the market offering of common stock				50,000,000
Unrestricted cash				$ 20,000,000
Term loan | Term Loans | Subsequent Event
Debt Instrument [Line Items]
Proceeds from at the market offering of common stock	$ 50,000,000

Common and Preferred Stock - Na

Common and Preferred Stock - Narrative (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares	Mar. 31, 2022 USD ($)	Dec. 31, 2022 shares	May 10, 2022 USD ($)
Class of Stock [Line Items]
Common stock authorized (shares)	200,000,000
Dividends declared | $	$ 0
Proceeds from at the market offering of common stock | $	$ 8,713,000	$ 0
Preferred stock authorized (shares)	5,000,000
Preferred stock issued (shares)	0		0
Preferred stock outstanding (shares)	0		0
ATM Offering
Class of Stock [Line Items]
Sales commissions, percentage				0.030
Issuance of common stock from at the market offering, net of issuance costs (shares)	7,651,816
Price per share (in usd per share) | $ / shares	$ 3.35
Proceeds from at the market offering of common stock | $	$ 24,300,000
Maximum | ATM Offering
Class of Stock [Line Items]
Common stock, amount authorized | $				$ 50,000,000

Common and Preferred Stock - Sc

Common and Preferred Stock - Schedule of Common Stock Reserved for Issuance (Details) - shares shares in Thousands	Mar. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock available for issuance (shares)	8,141	6,565
Shares reserved for exercises of outstanding stock options
Class of Stock [Line Items]
Common stock available for issuance (shares)	6,665	5,244
Shares reserved for vesting of restricted stock units
Class of Stock [Line Items]
Common stock available for issuance (shares)	323	323
Warrants to purchase common stock
Class of Stock [Line Items]
Common stock available for issuance (shares)	59	59
Shares reserved for future issuance under the 2021 Stock Incentive Plan
Class of Stock [Line Items]
Common stock available for issuance (shares)	1,094	939

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2021 shares	Mar. 31, 2023 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Jan. 01, 2023 shares	Dec. 31, 2022 shares	Jan. 01, 2022 shares
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock available for issuance (shares)		8,141,000			6,565,000
Weighted-average grant date fair value of awards (in usd per share) | $ / shares		$ 1.48	$ 7.54
Share-based compensation expense not yet recognized | $		$ 18,600
Total stock-based compensation | $		$ 2,108	$ 1,745
Exercise of common stock options (shares)		0
Aggregate intrinsic fair value of options exercised | $			$ 300
2021 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Maximum number of shares to be added annually, as a percentage of outstanding shares (percent)	5%
2017 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock available for issuance (shares)		1,093,993
2021 Stock Employee Stock Purchase Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense not yet recognized | $		$ 100
Offering period	6 months
Employee Stock Ownership Plan, Purchase Price, Percent	0.85
Risk-free interest rate	4.70%
Expected term (in years)	6 months
Expected volatility	77%
Dividend yield	0%
Total stock-based compensation | $		100
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	15%
Common Stock
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock authorized to be issued (shares)	3,352,725
Exercise of common stock options (shares)			46,000
Common Stock | 2021 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock authorized to be issued (shares)	2,843,116			1,575,753		1,380,397
Common Stock | 2017 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock authorized to be issued (shares)	31,884
Unvested RSAs | 2017 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense not yet recognized | $		$ 100
Share-based compensation not yet recognized, recognition period		2 months 12 days
Aggregate fair value of awards that vested | $		$ 100	$ 500
Vested (shares)		43,000
Granted (shares)		0
Weighted Average Grant Date Fair Value - Granted (in usd per share) | $ / shares		$ 0
Unvested RSAs | 2021 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock authorized to be issued (shares)	477,725
Stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation not yet recognized, recognition period		2 years 1 month 6 days
Risk-free interest rate		3.90%	1.60%
Expected term (in years)		6 years	6 years
Expected volatility		82.60%	76%
Dividend yield		0%	0%
Employee stock | 2021 Stock Employee Stock Purchase Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock authorized to be issued (shares)	244,000			315,150
Maximum number of shares to be added annually, as a percentage of outstanding shares (percent)	1%
Employee stock | 2021 Stock Employee Stock Purchase Plan | Minimum
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Maximum number of shares to be added annually, as a percentage of outstanding shares (shares)	488,000
Shares reserved for vesting of restricted stock units | 2021 Stock Incentive Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense not yet recognized | $		$ 800
Share-based compensation not yet recognized, recognition period		1 year
Vested (shares)		0
Granted (shares)		0
Weighted Average Grant Date Fair Value - Granted (in usd per share) | $ / shares		$ 0
Performance Shares
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Vested (shares)		0
Granted (shares)		883,352
Weighted Average Grant Date Fair Value - Granted (in usd per share) | $ / shares		$ 3.36

Stock-based Compensation - Expe

Stock-based Compensation - Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 2,108	$ 1,745
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	1,020	781
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 1,088	$ 964

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Award Activity (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Unvested RSAs | 2017 Stock Incentive Plan
Shares/Units
Unvested at beginning of period (shares) | shares	81,000
Granted (shares) | shares	0
Vested (shares) | shares	(43,000)
Forfeited (shares) | shares	0
Unvested at end of period (shares) | shares	38,000
Weighted-Average Grant Date Fair Value Per Share
Weighted Average Grant Date Fair Value - Unvested at beginning of period (in usd per share) | $ / shares	$ 1.38
Weighted Average Grant Date Fair Value - Granted (in usd per share) | $ / shares	0
Weighted Average Grant Date Fair Value - Vested (in usd per share) | $ / shares	1.37
Weighted Average Grant Date Fair Value - Forfeited (in usd per share) | $ / shares	0
Weighted Average Grant Date Fair Value - Unvested at end of period (in usd per share) | $ / shares	$ 1.38
Unvested RSUs | 2021 Stock Incentive Plan
Shares/Units
Unvested at beginning of period (shares) | shares	323,000
Granted (shares) | shares	0
Vested (shares) | shares	0
Forfeited (shares) | shares	0
Unvested at end of period (shares) | shares	323,000
Weighted-Average Grant Date Fair Value Per Share
Weighted Average Grant Date Fair Value - Unvested at beginning of period (in usd per share) | $ / shares	$ 4.32
Weighted Average Grant Date Fair Value - Granted (in usd per share) | $ / shares	0
Weighted Average Grant Date Fair Value - Vested (in usd per share) | $ / shares	0
Weighted Average Grant Date Fair Value - Forfeited (in usd per share) | $ / shares	0
Weighted Average Grant Date Fair Value - Unvested at end of period (in usd per share) | $ / shares	$ 4.32

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Assumptions (Details) - Stock options	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Risk-free interest rate	3.90%	1.60%
Expected term (in years)	6 years	6 years
Dividend yield	0%	0%
Expected volatility	82.60%	76%

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Details) - $ / shares	3 Months Ended	6 Months Ended
	Mar. 31, 2023	Jun. 30, 2022
Number of Options
Outstanding at beginning of period (shares)	5,244,000
Granted (shares)	1,429,000
Exercised (shares)	0
Cancelled (shares)	(8,000)
Outstanding at end of period (shares)	6,665,000
Exercisable at end of period (shares)	2,011,000
Weighted-Average Exercise Price
Weighted-Average Exercise Price - Outstanding at beginning of period (in usd per share)	$ 7.86
Weighted-Average Exercise Price - Granted (in usd per share)	2.05
Weighted-Average Exercise Price - Exercised (in usd per share)	0
Weighted-Average Exercise Price - Cancelled (in usd per share)	15.45
Weighted-Average Exercise Price - Outstanding at end of period (in usd per share)	6.60
Weighted-Average Exercise Price - Exercisable at end of period (in usd per share)	$ 7.87
Weighted-Average Remaining Contractual Life (in years)
Weighted Average Remaining Contractual Life - Outstanding	8 years 7 months 9 days	8 years 4 months 2 days
Weighted Average Remaining Contractual Life - Exercisable	7 years 11 months 15 days

Related Parties (Details)

Related Parties (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Related Party Transactions [Abstract]
Sublease income	$ (0.4)
Security deposit liability	$ 0.2

Net (Loss) Income Attributabl_2

Net (Loss) Income Attributable to Common Stockholders per Share - Antidilutive Shares (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	7,085,000	4,426,000
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	6,665,000	4,133,000
Unvested RSAs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	38,000	234,000
Unvested RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	323,000	0
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	59,000	59,000

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Millions		1 Months Ended
	Apr. 17, 2023	May 05, 2023
Subsequent Event
Subsequent Event [Line Items]
Success fee liability paid	$ 1.6	$ 1.6