Cyteir Therapeutics (CYT) 10-Q 7 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 03, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Registrant Name	Cyteir Therapeutics, Inc.
Entity Central Index Key	0001662244
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		35,438,912
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Security12b Title	Common Stock, par value $0.001 per share
Trading Symbol	CYT
Security Exchange Name	NASDAQ
Entity File Number	001-40499
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	45-5429901
Entity Address Address Line One	128 Spring St, Building A
Entity Address, Address Line Two	Suite 510
Entity Address City Or Town	Lexington
Entity Address State Or Province	MA
Entity Address Postal Zip Code	02421
City Area Code	857
Local Phone Number	285-4140
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 153,890	$ 189,723
Prepaid expenses and other current assets	3,458	3,354
Total current assets	157,348	193,077
Property and equipment, net	1,869	2,055
Other assets	2,479	256
Total assets	161,696	195,388
Current liabilities:
Accounts payable	1,666	1,785
Accrued expenses and other current liabilities	4,150	5,726
Total current liabilities	5,816	7,511
Deferred rent, net of current portion		384
Other long term liabilities	1,847	201
Total liabilities	7,663	8,096
Commitments and Contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.001 par value: 40,000,000 shares authorized as of September 30, 2022 and December 31, 2021; no shares issued and outstanding as of September 30, 2022 and December 31, 2021
Common stock, $0.001 par value: 280,000,000 shares authorized as of September 30, 2022 and December 31, 2021; 35,438,912 and 35,389,453 shares issued as of September 30, 2022 and December 31, 2021, respectively; 35,354,141 and 35,219,834 shares outstanding as of September 30, 2022 and December 31, 2021, respectively	35	35
Additional paid-in capital	283,319	279,310
Accumulated deficit	(129,321)	(92,053)
Total stockholders' equity	154,033	187,292
Total liabilities, redeemable convertible preferred stock and stockholders' equity	$ 161,696	$ 195,388

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	40,000,000	40,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	280,000,000	280,000,000
Common stock, shares issued	35,438,912	35,389,453
Common stock, shares outstanding	35,354,141	35,219,834

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating expenses:
Research and development	$ 8,272	$ 8,205	$ 27,154	$ 22,704
General and administrative	3,487	3,547	10,963	7,693
Total operating expenses	11,759	11,752	38,117	30,397
Loss from operations	(11,759)	(11,752)	(38,117)	(30,397)
Other income (expense):
Other income (expense)	714	48	849	86
Total other income (expense)	714	48	849	86
Net loss	$ (11,045)	$ (11,704)	$ (37,268)	$ (30,311)
Net loss per share--basic	$ (0.31)	$ (0.33)	$ (1.06)	$ (2.13)
Net loss per share--diluted	$ (0.31)	$ (0.33)	$ (1.06)	$ (2.13)
Weighted-average common stock outstanding--basic	35,329,137	35,062,900	35,283,454	14,229,834
Weighted-average common stock outstanding--diluted	35,329,137	35,062,900	35,283,454	14,229,834

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Series C Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2020	$ (48,031)				$ 2	$ 1,894	$ (49,927)
Redeemable convertible preferred stock, Shares at Dec. 31, 2020		5,817,996	55,200,000
Redeemable convertible preferred stock at Dec. 31, 2020	51,715	$ 5,696
Balance, Shares at Dec. 31, 2020					2,044,284
Exercise of common stock options	154					154
Exercise of common stock options, Shares					49,235
Issuance of Series C redeemable convertible preferred stock, net of issuance costs of $345				$ 79,655
Issuance of Series C redeemable convertible preferred stock, net of issuance costs of $345, Shares				21,784,885
Vesting of early exercised options	196					196
Vesting of early exercised options, Shares					172,640
Stock-based compensation expense	488					488
Net loss	(7,312)						(7,312)
Balance at Mar. 31, 2021	(54,505)				$ 2	2,732	(57,239)
Redeemable convertible preferred stock, Shares at Mar. 31, 2021		5,817,996	55,200,000	21,784,885
Redeemable convertible preferred stock at Mar. 31, 2021		$ 5,696	$ 51,715	$ 79,655
Balance, Shares at Mar. 31, 2021					2,266,159
Balance at Dec. 31, 2020	(48,031)				$ 2	1,894	(49,927)
Redeemable convertible preferred stock, Shares at Dec. 31, 2020		5,817,996	55,200,000
Redeemable convertible preferred stock at Dec. 31, 2020	51,715	$ 5,696
Balance, Shares at Dec. 31, 2020					2,044,284
Net loss	(30,311)
Balance at Sep. 30, 2021	197,842				$ 35	278,045	(80,238)
Balance, Shares at Sep. 30, 2021					35,105,537
Balance at Mar. 31, 2021	(54,505)				$ 2	2,732	(57,239)
Redeemable convertible preferred stock, Shares at Mar. 31, 2021		5,817,996	55,200,000	21,784,885
Redeemable convertible preferred stock at Mar. 31, 2021		$ 5,696	$ 51,715	$ 79,655
Balance, Shares at Mar. 31, 2021					2,266,159
Exercise of common stock options	40					40
Exercise of common stock options, Shares					15,987
Vesting of early exercised options	150					150
Vesting of early exercised options, Shares					131,861
Initial public offering, net of underwriting discounts, commissions and offering costs	121,627				$ 7	121,620
Initial public offering, net of underwriting discounts, commissions and offering costs, Shares					7,400,000
Conversion of convertible preferred stock into common stock upon initial public offering	137,066	$ (5,696)	$ (51,715)	$ (79,655)	$ 25	137,041
Conversion of convertible preferred stock into common stock upon initial public offering, Shares		(5,817,996)	(55,200,000)	(21,784,885)	24,290,875
Stock-based compensation expense	772					772
Net loss	(11,295)						(11,295)
Balance at Jun. 30, 2021	193,855				$ 34	262,355	(68,534)
Balance, Shares at Jun. 30, 2021					34,104,882
Exercise of common stock options	15					15
Exercise of common stock options, Shares					13,407
Vesting of early exercised options	110					110
Vesting of early exercised options, Shares					101,604
Initial public offering, net of underwriting discounts, commissions and offering costs	14,494				$ 1	14,493
Initial public offering, net of underwriting discounts, commissions and offering costs, Shares					885,644
Stock-based compensation expense	1,072					1,072
Net loss	(11,704)						(11,704)
Balance at Sep. 30, 2021	197,842				$ 35	278,045	(80,238)
Balance, Shares at Sep. 30, 2021					35,105,537
Balance at Dec. 31, 2021	187,292				$ 35	279,310	(92,053)
Balance, Shares at Dec. 31, 2021					35,219,834
Exercise of common stock options	19					19
Exercise of common stock options, Shares					19,575
Vesting of early exercised options	39					39
Vesting of early exercised options, Shares					32,605
Stock-based compensation expense	1,255					1,255
Net loss	(14,102)						(14,102)
Balance at Mar. 31, 2022	174,503				$ 35	280,623	(106,155)
Balance, Shares at Mar. 31, 2022					35,272,014
Balance at Dec. 31, 2021	$ 187,292				$ 35	279,310	(92,053)
Balance, Shares at Dec. 31, 2021					35,219,834
Exercise of common stock options, Shares	30,085
Net loss	$ (37,268)
Balance at Sep. 30, 2022	154,033				$ 35	283,319	(129,321)
Balance, Shares at Sep. 30, 2022					35,354,141
Balance at Mar. 31, 2022	174,503				$ 35	280,623	(106,155)
Balance, Shares at Mar. 31, 2022					35,272,014
Exercise of common stock options	5					5
Exercise of common stock options, Shares					4,398
Vesting of early exercised options	32					32
Vesting of early exercised options, Shares					26,732
Stock-based compensation expense	1,365					1,365
Net loss	(12,121)						(12,121)
Balance at Jun. 30, 2022	163,784				$ 35	282,025	(118,276)
Balance, Shares at Jun. 30, 2022					35,303,144
Exercise of common stock options	7					7
Exercise of common stock options, Shares					6,112
Vesting of early exercised options	30					30
Vesting of early exercised options, Shares					25,511
Issuance of common stock under ESPP	64					64
Issuance of common stock under ESPP, Shares					19,374
Stock-based compensation expense	1,193					1,193
Net loss	(11,045)						(11,045)
Balance at Sep. 30, 2022	$ 154,033				$ 35	$ 283,319	$ (129,321)
Balance, Shares at Sep. 30, 2022					35,354,141

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Series C Redeemable Convertible Preferred Stock
Stock issuance costs	$ 345

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss			$ (37,268)	$ (30,311)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	$ 200	$ 100	498	339
Stock-based compensation	1,193	1,072	3,813	2,332
Non-cash lease expense			551
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			(179)	(3,204)
Other assets				61
Accounts payable			(119)	1,587
Accrued expenses and other current liabilities			(2,912)	2,806
Other long term liabilities			1	(1)
Deferred rent				(24)
Net cash used in operating activities			(35,615)	(26,415)
Cash flows from investing activities:
Purchases of property and equipment			(312)	(686)
Net cash used in investing activities			(312)	(686)
Cash flows from financing activities:
Proceeds from issuance of preferred stock, net of issuance costs				79,655
Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts, commissions and offering costs of $12,412				136,121
Proceeds from issuance of common stock under ESPP			64
Proceeds from exercise of stock options			31	209
Net cash provided by financing activities			95	215,985
Net (decrease) increase in cash, cash equivalents, and restricted cash			(35,832)	188,884
Cash, cash equivalents and restricted cash at beginning of period			189,979	11,194
Cash, cash equivalents and restricted cash at end of period	154,147	200,078	154,147	200,078
Supplemental disclosure of noncash financing activities
Vesting of early exercised options			101	456
Initial public offering costs included in accounts payable and accrued expenses				608
Conversion of preferred stock to common stock upon initial public offering				137,066
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	153,890	199,822	153,890	199,822
Restricted cash (included in other assets)	$ 257	$ 256	$ 257	$ 256
Restricted Cash and Cash Equivalents, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 154,147	$ 200,078	$ 154,147	$ 200,078

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Statement of Cash Flows [Abstract]
Underwriting discounts, commissions and offering costs	$ 12,412

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Nature Of the Business	1. Nature of the business Cyteir Therapeutics, Inc., (the “Company”) is a clinical-stage biotechnology company focused on discovering and developing the next-generation of precision oncology medicines that cause cancer cell death in specific subsets of cancer patients through a therapeutic strategy known as synthetic lethality. Synthetic lethality is a clinically validated approach to drug development and arises when the occurrence of two cellular conditions is lethal when occurring simultaneously but tolerated when occurring individually. The Company was formed as a Delaware corporation on June 4, 2012, pursuant to the General Corporation Law of the State of Delaware. The Company has a principal office in Lexington, Massachusetts. Liquidity The Company has incurred net operating losses since inception and has funded its operations primarily with proceeds from the sale of redeemable convertible preferred stock and the issuance of common stock in the IPO. As of September 30, 2022, the Company had cash and cash equivalents of $ 153.9 million and an accumulated deficit of $ 129.3 million. The Company expects its operating losses and negative operating cash flows to continue into the foreseeable future as it continues to expand its research and development efforts. The Company expects that its cash and cash equivalents as of September 30, 2022 will be sufficient to fund its operating expenses and capital expenditure requirements for at least twelve months from the date these condensed consolidated financial statements are available to be issued. The Company will need additional funding to support its planned operating activities. There can be no assurances, however, that the current operating plan will be achieved or that additional funding will be available on terms acceptable to the Company, or at all. If the Company is unable to obtain sufficient funding, it could be required to delay its development efforts, limit activities and reduce research and development costs, which could adversely affect its business prospects. COVID-19 considerations The development of the Company’s product candidates could be disrupted and materially adversely affected in by a pandemic, epidemic or outbreak of an infectious disease, such as the ongoing COVID-19 pandemic. The ongoing COVID-19 pandemic and the measures taken by the governments of countries affected by it could disrupt the supply chain and the manufacture or shipment of both drug substance and finished drug product for the Company’s product candidates for preclinical testing or clinical trials, cause diversion of healthcare resources away from the conduct of preclinical and clinical trial matters to focus on pandemic concerns, limit travel in a manner that interrupts key trial activities, such as trial site initiations and monitoring, delay regulatory filings with regulatory agencies in affected areas or adversely affect the Company’s ability to obtain regulatory approvals. These disruptions could also affect other facets of the Company’s business, including, but not limited to, the Company’s ability to recruit employees from outside of the United States, the ability of the Company’s CROs to conduct clinical trials and preclinical studies in countries outside of the United States, the Company’s ability to import materials from outside of the United States, including raw materials required to manufacture its drug candidates, the Company’s ability to export materials to its CROs and other third-parties located outside of the United States, the Company’s ability to identify suitable clinical sites or open those sites for enrollment due to competing business needs, the Company’s ability to enroll patients due to their fear of coming into medical facilities and their perceived risk of becoming infected at such facilities, and the Company’s ability to monitor the clinical data generated at its clinical sites, required for completion of clinical trials. The COVID-19 pandemic and mitigation measures also may have an adverse impact on global economic conditions, which could adversely impact the Company’s business, financial condition or results of operations. Additionally, the COVID-19 pandemic has resulted in significant financial market volatility and uncertainty. A continuation or worsening of the levels of market disruption and volatility as a result of the COVID-19 pandemic could have an adverse effect on the Company’s ability to access capital and on the market price of its common stock. The Company cannot presently predict the scope and severity of any potential business shutdowns or disruptions, but if the Company or any of the third parties on whom it relies on or with whom it conducts business, were to experience shutdowns or other business disruptions, the Company’s ability to conduct business in the manner and on the timelines presently planned could be materially and adversely impacted.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies The Company's significant accounting policies are disclosed in the audited consolidated financial statements for the years ended December 31, 2021 and 2020 ("audited financial statements"), which are included in the Company's Annual Report on Form 10-K that was filed with the SEC on March 16, 2022. Since the date of the financial statements, there have been no changes to the Company's significant accounting policies, except as noted below. Interim Financial Information The accompanying condensed consolidated balance sheet at September 30, 2022, and the condensed consolidated statements of operations, statements of redeemable convertible preferred stock and changes in stockholders’ equity (deficit) for the three and nine months ended September 30, 2022 and 2021 and condensed consolidated statements of cash flows for the nine months ended September 30, 2022 and 2021 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position at September 30, 2022 and the results of its operations for the three and nine months ended September 30, 2022 and 2021 and its cash flows for the nine months ended September 30, 2022 and 2021. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2022 and 2021 are also unaudited. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of results to be expected for the full year or for any other subsequent interim period. Leases Prior to January 1, 2022, the Company accounted for leases in accordance with Accounting Standards Codification (“ASC”) 840, Leases. At lease inception, the Company determined if an arrangement was an operating or capital lease. For operating leases, the Company recognized rent expense, inclusive of rent escalations and lease incentives, on a straight-line basis over the lease term. Effective January 1, 2022, the Company adopted ASC 842, Leases (“ASC 842”), and elected to apply the modified retrospective transition approach using the effective date as the initial date of application. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. At the lease commencement date, when control of the underlying asset is transferred from the lessor to the Company, the Company classifies a lease as either an operating or finance lease and recognizes a right-of-use (“ROU”) asset and a current and non-current lease liability, as applicable, on the consolidated balance sheet if the lease has a term greater than one year. As permitted under ASC 842, the Company has made an accounting policy election, for all classes of underlying assets, to not recognize ROU assets and lease liabilities for leases having a term of twelve months or less. When it determines the appropriate classification and accounting for a lease arrangement, the Company typically only considers the committed lease term. Options to extend a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will either renew or not cancel, respectively. At the lease commencement date, the operating lease liability and corresponding ROU asset are recorded at the present value of future lease payments over the expected remaining lease term using the discount rate implicit in the lease, if it is readily determinable, or the Company’s incremental borrowing rate. The Company’s incremental borrowing rate reflects the fixed rate at which the Company could borrow the amount of lease payments in the same currency on a collateralized basis, for a similar term in a similar economic environment. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. In addition, certain adjustments to the ROU asset may be required for items such as lease prepayments, incentives received, or initial direct costs. The Company enters into contracts that contain both lease and non-lease components. Non-lease components include costs that do not provide a right-to-use a leased asset but instead provide a service, such as maintenance costs. After its adoption of ASC 842, the Company has elected to combine the lease and non-lease components together as a single lease component for all existing classes of underlying assets. Variable costs associated with the lease, such as maintenance and utilities, are not included in the measurement of right-to-use assets and lease liabilities but rather are expensed when the events determining the amount of variable consideration to be paid have occurred. Upon its adoption of ASC 842 on January 1, 2022 , the Company recorded a lease liability and its corresponding ROU asset based on the present value of lease payments over the remaining lease term. The adoption of ASC 842 resulted in the recognition of an operating lease liability of $ 3.2 million and ROU assets of $ 2.8 million, with the offset attributed to the net derecognition of prepaid rent and the unamortized deferred rent liability, inclusive of tenant improvement allowances on the Company’s balance sheet as of January 1, 2022. The adoption of ASC 842 did not have a material impact on the Company’s statements of operations and comprehensive loss or statements of cash flows. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued Accounting Standards Update No. 2019-12 (ASU 2019-12) Simplifying the Accounting for Income Tax. The standard contains several provisions that reduce financial statement complexity including removing the exception to the incremental approach for intra-period tax expense allocation when a company has a loss from continuing operations and income from other items not included in continuing operations. The new guidance is effective for the year beginning January 1, 2022 with optional adoption prior to the effective date. The Company adopted ASU 2019-12 on January 1, 2022 . There was no material impact to the Company’s consolidated financial statements as a result of adopting this new standard.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurement	3. Fair value measurement The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): September 30, 2022 Assets: Total Quoted prices in Significant Significant Cash equivalents: Money market funds $ 153,678 $ 153,678 $ — $ — Total assets $ 153,678 $ 153,678 $ $ December 31, 2021 Assets Total Quoted prices in Significant Significant Cash equivalents: Money market funds $ 189,488 $ 189,488 $ — $ — Total assets $ 189,488 $ 189,488 $ — $ — During the nine months ended September 30, 2022 and the year ended December 31, 2021 , there were no transfers between levels. The fair values of the Company’s cash equivalents, consisting of its standard checking accounts and money market funds, are based on quoted market prices in active markets without any valuation adjustment. The Company uses the carrying amounts of its restricted cash, prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities to approximate their fair value due to the short-term nature of these amounts.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	4. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands): September 30, December 31, Prepaid research and development expenses $ 1,524 $ 1,549 Prepaid insurance 1,512 1,397 Payroll tax credit 17 38 Prepaid other 405 370 Total $ 3,458 $ 3,354

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5. Property and equipment, net Property and equipment, net consisted of the following (in thousands): September 30, December 31, Laboratory and computer equipment $ 1,846 $ 1,541 Leasehold improvements 1,675 1,668 Total property and equipment 3,521 3,209 Less: accumulated depreciation and amortization ( 1,652 ) ( 1,154 ) Property and equipment, net $ 1,869 $ 2,055 For the three months ended September 30, 2022 and 2021 , depreciation and amortization expense related to property and equipment was $ 0.2 million and $ 0.1 million, respectively. For the nine months ended September 30, 2022 and 2021 , depreciation and amortization expense related to property and equipment was $ 0.5 million and $ 0.3 million, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued expenses and other current liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, Accrued research and development expenses $ 934 $ 3,448 Accrued compensation 1,920 1,660 Accrued other 396 618 Operating lease liabilities 900 — Total accrued expenses and other current liabilities $ 4,150 $ 5,726

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Common Stock	7. Common stock The voting, dividend and liquidation rights of the holders of the Company’s common stock are subject to and qualified by the rights, powers and preferences of the holders of the preferred stock as set forth in our Form 10-K for the fiscal year ended December 31, 2021. The holders of the common stock are entitled to one vote for each share of common stock held submitted to a vote of stockholders (and written actions in lieu of meetings), and there are not any cumulative voting rights. Holders of common stock are entitled to received proportionately any dividends as may be declared by our board of directors subject to any preferential dividend rights of any series of preferred stock that we may designate and issue in the future. As of September 30, 2022 and December 31, 2021, the Company has reserved the following shares of common stock for the potential exercise of stock options: September 30, December 31, 2022 2021 Options to purchase common stock 3,659,788 2,778,963 Remaining shares reserved for future issuance 5,644,236 5,670,560 Total 9,304,024 8,449,523

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	8. Stock-based compensation 2012 Stock Incentive Plan The Company adopted the 2012 Stock Incentive Plan (the “2012 Plan”) in February 2016 pursuant to which the Company can issue incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and other stock awards. Recipients of stock options or stock appreciate rights shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to the estimated fair market value of such stock on the date of grant. The exercise price may be less than fair market value if the stock award is granted pursuant to an assumption or substitution for another stock award in the event of a merger or sale of the Company. The maximum term of options granted under the 2012 Plan is ten years , and stock options typically vest over a four-year period. The Board may assign vesting terms to the stock option grants as deemed appropriate. The Company also has the right of refusal to purchase any proposed disposition of shares issued under the 2012 Plan. The 2012 Plan allows for early exercise of all stock option grants if authorized by the Board at the time of grant. The shares of common stock issued from the early exercise of stock options are restricted and vest over time. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. At the discretion of the Board, unvested shares held by employees may accelerate vesting in the event of a change of control of the Company unless assumed or substituted by the acquirer or surviving entity. The 2012 Plan has been subsequently amended and provides for the issuance of up to 6,941,421 shares of common stock as of September 30, 2022 , of which 2,732,632 shares of common stock remained available for future grant under the 2012 Plan upon the effectiveness of the 2021 Equity Incentive Plan (the “2021 Plan”) and were made available for future issuance under the 2021 Plan. 2021 Equity Incentive Plan In June 2021, the Company’s board of directors adopted and the Company’s stockholders approved the 2021 Plan, which became effective immediately prior to the effectiveness of the registration statement for the initial public offering. The 2021 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. Upon effectiveness of the 2021 Plan, the number of shares of common stock reserved for issuance under the 2021 Plan was 5,932,632 , which represents 3,200,000 shares along with 2,732,632 shares of common stock reserved for issuance under the 2012 Plan that remained available for grant under the 2012 Plan immediately prior to the effectiveness of the 2021 Plan. Shares of the Company's common stock subject to outstanding awards granted under the 2012 Plan that expire unexercised or are terminated, surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right will become available for issuance under the 2021 Plan. Upon adoption of the 2021 Plan, the Company ceased the grant of additional awards under the 2012 Plan. The 2021 Plan includes an "evergreen" provision, which provides for an annual increase to be added on January 1st of each year beginning in 2022 and continuing through and including 2031 by the lesser of (i) 5 % of the number of shares of Stock outstanding as of such date and (ii) an amount determined by the board of directors. On January 1, 2022, the number of shares of Common Stock reserved and available for issuance under the 2021 Plan increased by 884,585 shares. At September 30, 2022, 5,644,236 shares of common stock remained available for future grant under the 2021 Plan. 2021 Employee Stock Purchase Plan In June 2021, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2021 Employee Stock Purchase Plan (the “ESPP”), which became effective immediately prior to the effectiveness of the registration statement for the initial public offering. The ESPP is administered by the compensation committee of the Company’s board of directors, except that the Company’s board of directors may at any time act as the administrator of the ESPP. The ESPP provides participating employees with the opportunity to purchase shares of common stock, with an initial aggregate share pool of 300,000 shares of common stock. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1st of each year beginning in 2022 and continuing through and including 2031 by the least of (i) 1% of the number of shares of Stock outstanding as of such date, (ii) 600,000 shares of Stock and (iii) the number of shares of Stock determined by the Company’s board of directors on or prior to such date for such year, up to a maximum of 6,300,000 shares in the aggregate. The ESPP allows eligible employees to authorize payroll deductions of between 1% and 15% of their regular base salary or wages to be applied toward the purchase of shares of the Company's common stock on the last trading day of the offering period, subject to certain limitations contained in the ESPP. Participating employees will purchase shares of the Company's common stock at a discount of 15% on the lesser of the closing price of the Company's common stock on the Nasdaq Global Select Market (i) on the first trading day of the offering period or (ii) the last trading day of the offering period. The Company utilizes the Black Scholes option pricing model to compute the fair market value of the shares subject to outstanding options under the ESPP and compensation expense is recognized over the offering period. Participation in the ESPP is voluntary. Eligible employees become participants in the ESPP by enrolling in the plan and authorizing payroll deductions in accordance with the terms of the ESPP. At the end of each offering period, accumulated payroll deductions are used to purchase the Company’s shares at the discounted price. The Company makes no contributions to the ESPP. A participant may withdraw from the ESPP or reduce contributions to the ESPP during an offering period. If the participant elects to withdraw during an offering period, all contributions are refunded as soon as administratively practicable. If a participant elects to withdraw during an offering period, the participant may not re-enroll in the current offering but may elect to participate in future offerings, subject to the terms of the ESPP. Only whole shares of the Company may be purchased under the ESPP. The Company issued 19,374 common shares under the ESPP during the nine months ended September 30, 2022 at an average price per share of $ 3.32 . Cash received from purchases under the ESPP for the nine months ended September 30, 2022 wa s $ 0.1 million. The Company recognized $ 0.1 million of compensation expense for the ESPP during the nine months ended September 30, 2022. Early exercise of unvested stock options Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding shares until those shares vest according to their respective vesting schedules. Cash received from employee exercises of unvested options is included in long-term liabilities on the condensed consolidated balance sheets. Amounts recorded are reclassified to common stock and additional paid-in capital as the shares vest. As of September 30, 2022 and December 31, 2021, there wer e 84,771 and 169,919 unvested shares related to early exercises of stock options, respectively. Stock option valuation The assumptions that the Company used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted were as follows: September 30, December 31, Risk-free interest rate range 1.89 - 3.38 % 0.75 - 1.35 % Dividend yield 0.0 % 0.0 % Expected life of options (years) 6.0 5.5 - 6.1 Volatility rate range 92.4 %- 93.7 % 93.6 %- 97.1 % The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2022: Number of Weighted average Weighted average Aggregate intrinsic Outstanding as of December 31, 2021 2,778,963 $ 5.80 8.76 $ 17,102 Granted 1,037,159 $ 4.63 — — Exercised ( 30,085 ) $ 1.03 — — Forfeited or cancelled ( 126,249 ) $ 6.35 — — Outstanding as of September 30, 2022 3,659,788 $ 5.50 8.36 $ 752 Options vested and exercisable as of September 30, 2022 1,385,082 $ 5.49 7.85 $ 427 As of September 30, 2022 , there was $8.7 million of unrecognized stock-based compensation expense related to the share-based compensation arrangements under the 2012 Plan. The Company expects to recognize this amount over a weighted-average period of 2.2 years. The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the reporting period. The weighted-average grant date fair value of the Company’s stock options granted during the three months ended September 30, 2022 and 2021 was $ 1.78 and $ 15.05 , respectively. The total fair value of options vested during the three months ended September 30, 2022 and 2021 was $1.8 million and $ 0.6 million, respectively. Stock-based compensation expense Stock-based compensation expense included in the Company’s condensed consolidated statements of operations is as follows (in thousands): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Research and development $ 505 $ 349 $ 1,393 $ 775 General and administrative 688 723 2,420 1,557 Total stock-based compensation expense $ 1,193 $ 1,072 $ 3,813 $ 2,332

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net loss per share The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following shares from the computation of diluted net loss per share attributable to common stockholders as of September 30, 2022 and 2021 because including them would have had an anti-dilutive effect: Nine Months Ended 2022 2021 Options to purchase common stock 3,659,788 2,714,532 Unvested shares from early exercises 84,771 267,835

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Legal proceedings From time to time, in the ordinary course of business, the Company is subject to litigation and regulatory examinations as well as information gathering requests, inquiries and investigations. As of September 30, 2022, there were no matters which would have a material impact on the Company’s financial results.

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	11. Leases Operating Lease In August 2018, the Company entered into an operating lease agreement for office and laboratory space within the building complex located in Lexington, Massachusetts. The lease commenced in November 2018, and as subsequently amended, is approximately 14,636 rentable square feet (“Original Premises”) and has a maturity date of October 31, 2023 . In July 2021, the Company entered into the second amendment of the lease and expanded the office space by approximately 5,531 square feet (the “Expansion Premises”), and extended the maturity date to December 31, 2025 for both the Original Premises and Expansion Premises. Lease payments are made monthly, subject to a 3 % annual rent increase, and the Company pays for its proportionate share of building operating costs such as maintenance, utilities, and insurance that are treated as variable costs and excluded from the measurement of the lease. The following table summarizes the presentation of the Company's operating leases on its consolidated balance sheet: Leases Balance sheet classification September 30, 2022 Assets Operating lease assets Other assets $ 2,222 Liabilities Current Operating lease liabilities Accrued expenses and other current liabilities $ 900 Noncurrent Operating lease liabilities Other long term liabilities 1,746 Total lease liabilities $ 2,646 The components of lease cost under ASC 842 included in the Company’s consolidated statement of operations for the three and nine months ended September 30, 2022 were as follows: Three Months Ended Nine Months Ended Lease Cost Statement of operations classification September 30, 2022 September 30, 2022 Operating lease cost Research and development $ 143 $ 447 Operating lease cost General and administrative 44 124 Variable lease cost Research and development 100 344 Variable lease cost General and administrative 31 96 Total lease cost $ 318 $ 1,011 The weighted average remaining lease term and weighted average discount rate of the operating leases was 3.3 years and 5.0 %, respectively, at September 30, 2022 . The Company made cash payments for amounts included in the measurement of operating liabilities of $ 0.6 million for the nine months ended September 30, 2022. Future minimum lease payments under non-cancellable operating leases as of September 30, 2022 were as follows (in thousands): Maturity of lease liabilities Amount 2022 (excluding the nine months ended September 30, 2022) $ 228 2023 910 2024 883 2025 833 2026 — Total lease payments 2,854 Less: interest ( 208 ) Present value of operating lease liabilities $ 2,646 In accordance with ASC 840, rent expense for the three months ended September 30, 2021 was $ 0.1 million. Future minimum payments required under the lease as of December 31, 2021 were as follows (in thousands): Year Ending December 31, Amount 2022 $ 899 2023 913 2024 881 2025 908 $ 3,601

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Interim Financial Information	Interim Financial Information The accompanying condensed consolidated balance sheet at September 30, 2022, and the condensed consolidated statements of operations, statements of redeemable convertible preferred stock and changes in stockholders’ equity (deficit) for the three and nine months ended September 30, 2022 and 2021 and condensed consolidated statements of cash flows for the nine months ended September 30, 2022 and 2021 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position at September 30, 2022 and the results of its operations for the three and nine months ended September 30, 2022 and 2021 and its cash flows for the nine months ended September 30, 2022 and 2021. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2022 and 2021 are also unaudited. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of results to be expected for the full year or for any other subsequent interim period.
Leases	Leases Prior to January 1, 2022, the Company accounted for leases in accordance with Accounting Standards Codification (“ASC”) 840, Leases. At lease inception, the Company determined if an arrangement was an operating or capital lease. For operating leases, the Company recognized rent expense, inclusive of rent escalations and lease incentives, on a straight-line basis over the lease term. Effective January 1, 2022, the Company adopted ASC 842, Leases (“ASC 842”), and elected to apply the modified retrospective transition approach using the effective date as the initial date of application. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. At the lease commencement date, when control of the underlying asset is transferred from the lessor to the Company, the Company classifies a lease as either an operating or finance lease and recognizes a right-of-use (“ROU”) asset and a current and non-current lease liability, as applicable, on the consolidated balance sheet if the lease has a term greater than one year. As permitted under ASC 842, the Company has made an accounting policy election, for all classes of underlying assets, to not recognize ROU assets and lease liabilities for leases having a term of twelve months or less. When it determines the appropriate classification and accounting for a lease arrangement, the Company typically only considers the committed lease term. Options to extend a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will either renew or not cancel, respectively. At the lease commencement date, the operating lease liability and corresponding ROU asset are recorded at the present value of future lease payments over the expected remaining lease term using the discount rate implicit in the lease, if it is readily determinable, or the Company’s incremental borrowing rate. The Company’s incremental borrowing rate reflects the fixed rate at which the Company could borrow the amount of lease payments in the same currency on a collateralized basis, for a similar term in a similar economic environment. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. In addition, certain adjustments to the ROU asset may be required for items such as lease prepayments, incentives received, or initial direct costs. The Company enters into contracts that contain both lease and non-lease components. Non-lease components include costs that do not provide a right-to-use a leased asset but instead provide a service, such as maintenance costs. After its adoption of ASC 842, the Company has elected to combine the lease and non-lease components together as a single lease component for all existing classes of underlying assets. Variable costs associated with the lease, such as maintenance and utilities, are not included in the measurement of right-to-use assets and lease liabilities but rather are expensed when the events determining the amount of variable consideration to be paid have occurred. Upon its adoption of ASC 842 on January 1, 2022 , the Company recorded a lease liability and its corresponding ROU asset based on the present value of lease payments over the remaining lease term. The adoption of ASC 842 resulted in the recognition of an operating lease liability of $ 3.2 million and ROU assets of $ 2.8 million, with the offset attributed to the net derecognition of prepaid rent and the unamortized deferred rent liability, inclusive of tenant improvement allowances on the Company’s balance sheet as of January 1, 2022. The adoption of ASC 842 did not have a material impact on the Company’s statements of operations and comprehensive loss or statements of cash flows.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In December 2019, the FASB issued Accounting Standards Update No. 2019-12 (ASU 2019-12) Simplifying the Accounting for Income Tax. The standard contains several provisions that reduce financial statement complexity including removing the exception to the incremental approach for intra-period tax expense allocation when a company has a loss from continuing operations and income from other items not included in continuing operations. The new guidance is effective for the year beginning January 1, 2022 with optional adoption prior to the effective date. The Company adopted ASU 2019-12 on January 1, 2022 . There was no material impact to the Company’s consolidated financial statements as a result of adopting this new standard.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): September 30, 2022 Assets: Total Quoted prices in Significant Significant Cash equivalents: Money market funds $ 153,678 $ 153,678 $ — $ — Total assets $ 153,678 $ 153,678 $ $ December 31, 2021 Assets Total Quoted prices in Significant Significant Cash equivalents: Money market funds $ 189,488 $ 189,488 $ — $ — Total assets $ 189,488 $ 189,488 $ — $ —

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): September 30, December 31, Prepaid research and development expenses $ 1,524 $ 1,549 Prepaid insurance 1,512 1,397 Payroll tax credit 17 38 Prepaid other 405 370 Total $ 3,458 $ 3,354

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): September 30, December 31, Laboratory and computer equipment $ 1,846 $ 1,541 Leasehold improvements 1,675 1,668 Total property and equipment 3,521 3,209 Less: accumulated depreciation and amortization ( 1,652 ) ( 1,154 ) Property and equipment, net $ 1,869 $ 2,055

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, Accrued research and development expenses $ 934 $ 3,448 Accrued compensation 1,920 1,660 Accrued other 396 618 Operating lease liabilities 900 — Total accrued expenses and other current liabilities $ 4,150 $ 5,726

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Schedule of Common Stock for Potential Exercise of Stock Options	As of September 30, 2022 and December 31, 2021, the Company has reserved the following shares of common stock for the potential exercise of stock options: September 30, December 31, 2022 2021 Options to purchase common stock 3,659,788 2,778,963 Remaining shares reserved for future issuance 5,644,236 5,670,560 Total 9,304,024 8,449,523

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Assumptions Used in Black Scholes Option-Pricing Model to Determine Grant Fair Value of Stock Option	The assumptions that the Company used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted were as follows: September 30, December 31, Risk-free interest rate range 1.89 - 3.38 % 0.75 - 1.35 % Dividend yield 0.0 % 0.0 % Expected life of options (years) 6.0 5.5 - 6.1 Volatility rate range 92.4 %- 93.7 % 93.6 %- 97.1 %
Schedule of Stock Option Activity	The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2022: Number of Weighted average Weighted average Aggregate intrinsic Outstanding as of December 31, 2021 2,778,963 $ 5.80 8.76 $ 17,102 Granted 1,037,159 $ 4.63 — — Exercised ( 30,085 ) $ 1.03 — — Forfeited or cancelled ( 126,249 ) $ 6.35 — — Outstanding as of September 30, 2022 3,659,788 $ 5.50 8.36 $ 752 Options vested and exercisable as of September 30, 2022 1,385,082 $ 5.49 7.85 $ 427
Schedule of Stock Based Compensation Expense	Stock-based compensation expense included in the Company’s condensed consolidated statements of operations is as follows (in thousands): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Research and development $ 505 $ 349 $ 1,393 $ 775 General and administrative 688 723 2,420 1,557 Total stock-based compensation expense $ 1,193 $ 1,072 $ 3,813 $ 2,332

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Computation of Diluted Net Loss per Share Attributable to Common Stockholders	The Company excluded the following shares from the computation of diluted net loss per share attributable to common stockholders as of September 30, 2022 and 2021 because including them would have had an anti-dilutive effect: Nine Months Ended 2022 2021 Options to purchase common stock 3,659,788 2,714,532 Unvested shares from early exercises 84,771 267,835

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Summary of Operating Leases on Consolidated Balance Sheet	The following table summarizes the presentation of the Company's operating leases on its consolidated balance sheet: Leases Balance sheet classification September 30, 2022 Assets Operating lease assets Other assets $ 2,222 Liabilities Current Operating lease liabilities Accrued expenses and other current liabilities $ 900 Noncurrent Operating lease liabilities Other long term liabilities 1,746 Total lease liabilities $ 2,646
Components of Lease Cost	The components of lease cost under ASC 842 included in the Company’s consolidated statement of operations for the three and nine months ended September 30, 2022 were as follows: Three Months Ended Nine Months Ended Lease Cost Statement of operations classification September 30, 2022 September 30, 2022 Operating lease cost Research and development $ 143 $ 447 Operating lease cost General and administrative 44 124 Variable lease cost Research and development 100 344 Variable lease cost General and administrative 31 96 Total lease cost $ 318 $ 1,011
Schedule of Future Minimum Payments Required Under Non-cancellable Operating Leases	Future minimum lease payments under non-cancellable operating leases as of September 30, 2022 were as follows (in thousands): Maturity of lease liabilities Amount 2022 (excluding the nine months ended September 30, 2022) $ 228 2023 910 2024 883 2025 833 2026 — Total lease payments 2,854 Less: interest ( 208 ) Present value of operating lease liabilities $ 2,646
Future Minimum Payments under Leases	Future minimum payments required under the lease as of December 31, 2021 were as follows (in thousands): Year Ending December 31, Amount 2022 $ 899 2023 913 2024 881 2025 908 $ 3,601

Nature of the Business - Additi

Nature of the Business - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Subsidiary or Equity Method Investee [Line Items]
Accumulated deficit	$ (129,321)	$ (92,053)
Cash and cash equivalents	$ 153,890	$ 189,723	$ 199,822

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jan. 01, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Operating lease liability	$ 2,646
Operating lease ROU assets	$ 2,222
ASU 2016-02
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
Change in accounting principle, accounting standards update, immaterial effect [true false]	true
Operating lease liability		$ 3,200
Operating lease ROU assets		$ 2,800
ASU 2019-12
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
Change in accounting principle, accounting standards update, immaterial effect [true false]	true

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets:
Total assets	$ 153,678	$ 189,488
Money Market Funds
Assets:
Cash equivalents	153,678	189,488
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets	153,678	189,488
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Assets:
Cash equivalents	$ 153,678	$ 189,488

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair value of assets, Level 1 to Level 2 transfers, amount	$ 0	$ 0
Fair value of assets, Level 2 to Level 1 transfers, amount	$ 0	$ 0

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid research and development expenses	$ 1,524	$ 1,549
Prepaid insurance	1,512	1,397
Payroll tax credit	17	38
Prepaid other	405	370
Total	$ 3,458	$ 3,354

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Total property and equipment	$ 3,521	$ 3,209
Less: accumulated depreciation and amortization	(1,652)	(1,154)
Property and equipment, net	1,869	2,055
Laboratory and Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	1,846	1,541
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 1,675	$ 1,668

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 200	$ 100	$ 498	$ 339

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 934	$ 3,448
Accrued compensation	1,920	1,660
Accrued other	396	618
Operating lease liabilities	900
Total accrued expenses and other current liabilities	$ 4,150	$ 5,726

Common Stock - Additional Infor

Common Stock - Additional Information (Details)	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Common stock, voting rights	The holders of the common stock are entitled to one vote for each share of common stock held submitted to a vote of stockholders (and written actions in lieu of meetings), and there are not any cumulative voting rights.

Common Stock - Schedule of Comm

Common Stock - Schedule of Common Stock for Potential Exercise of Stock Options (Details) - shares	Sep. 30, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common stock issuable upon conversion	9,304,024	8,449,523
Options to Purchase Common Stock
Class Of Stock [Line Items]
Common stock issuable upon conversion	3,659,788	2,778,963
Remaining Shares Reserved for Future Issuance
Class Of Stock [Line Items]
Common stock issuable upon conversion	5,644,236	5,670,560

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Jan. 01, 2022	Jun. 21, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			9,304,024		9,304,024		8,449,523
Weighted average exercise price			$ 5.50		$ 5.50		$ 5.80
Compensation expense			$ 1,193	$ 1,072	$ 3,813	$ 2,332
Weighted-average grant date fair value of stock options granted			$ 1.78	$ 15.05
Weighted-average period					2 years 2 months 12 days
Total fair value of options vested				$ 600
Unvested Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares related to early exercises of stock options			84,771		84,771		169,919
2012 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum term of options granted					10 years
Vesting period					4 years
Common stock available for future grant			2,732,632		2,732,632
2012 Stock Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			6,941,421		6,941,421
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			5,932,632		5,932,632
Common stock available for future grant			5,644,236		5,644,236
Percentage of number of shares of stock outstanding		5%
Increase in common stock reserved and available for issuance	884,585
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from ESPP					$ 100
Compensation expense					$ 100
2021 Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued					19,374
Weighted average exercise price			$ 3.32		$ 3.32
Current Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			3,200,000		3,200,000
2012 Shares Made Available Under 2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			2,732,632		2,732,632

Stock-based Compensation - Assu

Stock-based Compensation - Assumptions Used in Black Scholes Option-Pricing Model to Determine Grant Fair Value of Stock Option (Details) - Stock Option	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate range, minimum	1.89%	0.75%
Risk-free interest rate range, maximum	3.38%	1.35%
Dividend yield	0%	0%
Expected life of options (years)	6 years
Volatility rate range, minimum	92.40%	93.60%
Volatility rate range, maximum	93.70%	97.10%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)		5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)		6 years 1 month 6 days

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of shares, beginning balance	2,778,963
Number of shares, Granted	1,037,159
Number of shares, Exercised	(30,085)
Number of shares, Forfeited or cancelled	(126,249)
Number of shares, ending balance	3,659,788	2,778,963
Number of shares, Options vested and exercisable	1,385,082
Weighted average exercise price, beginning balance	$ 5.80
Weighted average exercise price, Granted	4.63
Weighted average exercise price, Exercised	1.03
Weighted average exercise price, Forfeited or cancelled	6.35
Weighted average exercise price, ending balance	5.50	$ 5.80
Weighted average exercise price, Options vested and exercisable	$ 5.49
Weighted average remaining contractual term (in years), balance	8 years 4 months 9 days	8 years 9 months 3 days
Weighted average remaining contractual term (in years), Options vested and exercisable	7 years 10 months 6 days
Aggregate intrinsic value, beginning balance	$ 17,102
Aggregate intrinsic value, ending balance	752	$ 17,102
Aggregate intrinsic value, Options vested and exercisable	$ 427

Stock-based Compensation - Sc_2

Stock-based Compensation - Schedule of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,193	$ 1,072	$ 3,813	$ 2,332
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	505	349	1,393	775
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 688	$ 723	$ 2,420	$ 1,557

Net Loss per Share - Computatio

Net Loss per Share - Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	3,659,788	2,714,532
Unvested Shares from Early Exercises
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	84,771	267,835

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended
	Jul. 31, 2021 ft²	Aug. 31, 2018 ft²	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Rent expense | $			$ 0.1
Operating lease, weighted average remaining lease term				3 years 3 months 18 days
Operating lease, weighted average discount rate				5%
Operating lease, payments | $				$ 0.6
Premises | Massachusetts
Lessee, Lease, Description [Line Items]
Total rentable area | ft²		14,636
Lease expiration date		Oct. 31, 2023
Number of square feet expanding | ft²	5,531
Operating lease extended maturity date	Dec. 31, 2025
Description of option to extend operating lease				In July 2021, the Company entered into the second amendment of the lease and expanded the office space by approximately 5,531 square feet (the “Expansion Premises”), and extended the maturity date to December 31, 2025 for both the Original Premises and Expansion Premises.
Existence option to extend operating lease	true
Increase in annual rent percentage	3%

Leases - Summary of Operating L

Leases - Summary of Operating Leases on Consolidated Balance Sheet (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Assets
Operating lease assets	$ 2,222
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent
Liabilities
Operating lease liabilities, Current	$ 900
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Other Accrued Liabilities, Current
Operating lease liabilities, Noncurrent	$ 1,746
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent
Total lease liabilities	$ 2,646

Leases - Components of Lease Co

Leases - Components of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Lessee, Lease, Description [Line Items]
Total lease cost	$ 318	$ 1,011
Research and Development
Lessee, Lease, Description [Line Items]
Operating lease cost	143	447
Variable lease cost	100	344
General and Administrative
Lessee, Lease, Description [Line Items]
Operating lease cost	44	124
Variable lease cost	$ 31	$ 96

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Payments Required Under Non-cancellable Operating Leases (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Lessee, Operating Lease, Liability, to be Paid [Abstract]
2022 (excluding the nine months ended September 30, 2022)	$ 228
2023	910
2024	883
2025	833
2026	0
Operating lease liabilities, net of current portion	2,854
Less: interest	(208)
Present value of operating lease liabilities	$ 2,646

Leases - Future Minimum Payment

Leases - Future Minimum Payments under Leases (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2022	$ 899
2023	913
2024	881
2025	908
Total minimum lease payments	$ 3,601