Stoke Therapeutics (STOK) 10-K 6 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Feb. 23, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Registrant Name	Stoke Therapeutics, Inc.
Entity Central Index Key	0001623526
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well Known Seasoned Issuer	No
Entity Public Float			$ 297
Entity Common Stock, Shares Outstanding		44,147,687
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-38938
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	47-1144582
Entity Address, Address Line One	45 Wiggins Ave
Entity Address City Or Town	Bedford
Entity Address State Or Province	MA
Entity Address Postal Zip Code	01730
City Area Code	781
Local Phone Number	430-8200
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Auditor Firm ID	185
Auditor Name	KPMG LLP
Auditor Location	Boston, MA USA
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	STOK
Security Exchange Name	NASDAQ
Documents Incorporated by Reference	Portions of the registrant’s Definitive Proxy Statement relating to the 2023 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein. The Definitive Proxy Statement will be filed within 120 days of the Registrant’s fiscal year ended December 31, 2022. Except with respect to information specifically incorporated by reference in this Form 10-K, the Definitive Proxy Statement is not deemed to be filed as part of this Form 10-K. Auditor Firm Id: 185 Auditor Name: KPMG LLP Auditor Location: Boston, MA USA

Consolidated balance sheets

Consolidated balance sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 113,556	$ 144,895
Marketable securities	116,039	74,915
Prepaid expenses	10,932	6,943
Other current assets	2,955	2,216
Deferred financing costs		117
Interest receivable	588	132
Total current assets	244,070	229,218
Restricted cash	569	569
Operating lease right-of-use assets	4,753	4,939
Property and equipment, net	6,675	4,139
Total assets	256,067	238,865
Current liabilities:
Accounts payable	766	2,385
Accrued and other current liabilities	15,748	14,754
Deferred revenue - current portion	14,880
Total current liabilities	31,394	17,139
Deferred revenue - net of current portion	36,856
Other long term liabilities	2,968	3,949
Total long term liabilities	39,824	3,949
Total liabilities	71,218	21,088
Commitments and contingencies (Note 7)
Stockholders’ equity
Common stock, par value of $0.0001 per share; 300,000,000 shares authorized, 39,439,575 and 36,902,499 shares issued and outstanding as of December 31, 2022 and 2021, respectively	4	4
Additional paid-in capital	483,170	414,024
Accumulated other comprehensive loss	(1,175)	(168)
Accumulated deficit	(297,150)	(196,083)
Total stockholders’ equity	184,849	217,777
Total liabilities and stockholders’ equity	$ 256,067	$ 238,865

Consolidated balance sheets (Pa

Consolidated balance sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	39,439,575	36,902,499
Common stock, shares outstanding	39,439,575	36,902,499

Consolidated statements of oper

Consolidated statements of operations and comprehensive loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 12,405
Operating expenses:
Research and development	77,837	$ 54,168
General and administrative	38,924	31,897
Total operating expenses	116,761	86,065
Loss from operations	(104,356)	(86,065)
Other income (expense):
Interest income (expense), net	3,122	120
Other income (expense), net	167	140
Total other income (expense)	3,289	260
Net loss	$ (101,067)	$ (85,805)
Net loss per share, basic	$ (2.60)	$ (2.34)
Net loss per share, diluted	$ (2.60)	$ (2.34)
Weighted-average common shares outstanding, basic	38,897,442	36,739,269
Weighted-average common shares outstanding, diluted	38,897,442	36,739,269
Comprehensive loss:
Net loss	$ (101,067)	$ (85,805)
Other comprehensive loss:
Unrealized loss on marketable securities	(1,007)	(168)
Total other comprehensive loss	(1,007)	(168)
Comprehensive loss	$ (102,074)	$ (85,973)

Consolidated statements of stoc

Consolidated statements of stockholders' equity - USD ($) $ in Thousands	Total	Follow-on Offering	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Follow-on Offering	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit
Balance at Dec. 31, 2020	$ 286,078		$ 4	$ 396,352			$ (110,278)
Balance, Shares at Dec. 31, 2020			36,577,149
Unrealized loss on marketable securities	(168)					$ (168)
Stock-based compensation	16,450			16,450
Issuance of common stock upon exercise of stock options	777			777
Issuance of common stock upon exercise of stock options, Shares			304,857
Issuance of common stock related to employee stock purchase plan	509			509
Issuance of common stock related to employee stock purchase plan, Shares			20,493
Issuance of common stock		$ (64)			$ (64)
Net loss	(85,805)						(85,805)
Balance at Dec. 31, 2021	217,777		$ 4	414,024		(168)	(196,083)
Balance, Shares at Dec. 31, 2021			36,902,499
Unrealized loss on marketable securities	(1,007)					(1,007)
Stock-based compensation	22,854			22,854
Issuance of common stock upon exercise of stock options	$ 494			494
Issuance of common stock upon exercise of stock options, Shares	270,376		269,288
Issuance of common stock related to employee stock purchase plan	$ 570			570
Issuance of common stock related to employee stock purchase plan, Shares			44,002
Shares sold at the market	45,228			45,228
Shares sold at the market, Shares			2,223,786
Net loss	(101,067)						(101,067)
Balance at Dec. 31, 2022	$ 184,849		$ 4	$ 483,170		$ (1,175)	$ (297,150)
Balance, Shares at Dec. 31, 2022			39,439,575

Consolidated statements of cash

Consolidated statements of cash flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (101,067)	$ (85,805)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,546	974
Amortization and accretion of marketable securities	(211)	143
Stock-based compensation	22,854	16,450
Loss on disposal of property and equipment		29
Reduction in the carrying amount of right of use assets	1,989	1,256
Changes in assets and liabilities:
Prepaid expenses and other current assets	(5,183)	(2,851)
Accounts payable and accrued liabilities	(3,530)	2,897
Deferred revenue	51,736
Net cash used in operating activities	(31,866)	(66,907)
Cash flows from investing activities:
Purchases of property and equipment	(3,962)	(1,200)
Purchases of marketable securities	(201,320)	(87,226)
Sales of marketable securities	159,400	12,000
Net cash used in investing activities	(45,882)	(76,426)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	494	777
Proceeds from Employee Stock Purchase Plan	570	509
Proceeds from controlled equity offering sales agreement	45,344
Other	1	(2)
Net cash provided by financing activities	46,409	1,284
Net decrease in cash, cash equivalents and restricted cash	(31,339)	(142,049)
Cash, cash equivalents and restricted cash—beginning of year	145,464	287,513
Cash, cash equivalents and restricted cash—end of year	114,125	145,464
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Right-of-use assets recognized in exchange for operating leases	1,802	5,081
Property and equipment included in accrued expense and accounts payable	$ 121	$ 1,267

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Nature of the business and basis of presentation	1. Nature of the business and basis of presentation Organization Stoke Therapeutics, Inc. (the Company) was founded in June 2014 and was incorporated under the laws of the State of Delaware. The Company is an early-stage biopharmaceutical company pioneering a new way to treat the underlying causes of severe genetic diseases by precisely upregulating protein expression. Shelf Registration In July 2020, the Company filed a universal Shelf Registration statement on Form S-3 (the “Prior Registration Statement”) with the Securities and Exchange Commission (the “SEC”). The Prior Registration Statement was declared effective by the SEC on July 20, 2020, and contained two prospectuses: a base prospectus, which covered the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $400,000,000 of its common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150,000,000 of its common stock that may be issued and sold under a Controlled Equity Offering Sales Agreement (“Prior Sales Agreement”). On May 31, 2022, the Prior Registration Statement was deactivated upon the effectiveness of the Registration Statement (as defined below). As of such date, the Company had issued approximately 2.2 million shares of common stock in connection with the Prior Sales Agreement for net proceeds of $45.3 million. In May 2022, the Company filed an additional universal Shelf Registration statement on Form S-3 (the “Registration Statement”) with the SEC. The Registration Statement was declared effective by the SEC on May 31, 2022, and contains two prospectuses: a base prospectus, which covers the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $400,000,000 of its common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150,000,000 of its common stock that may be issued and sold under a Controlled Equity Offering Sales Agreement (“Sales Agreement”). The specific terms of any securities to be offered pursuant to the base prospectus will be specified in a prospectus supplement to the base prospectus. The $150,000,000 of common stock that may be offered, issued and sold under the sales agreement prospectus is included in the $400,000,000 of securities that may be offered, issued and sold by the Company under the base prospectus. As of December 31, 2022, the Company had not issued any shares pursuant to the Sales Agreement. Since December 31, 2022, we sold approximately 4.6 million shares of our common stock and received $44.7 million after deducting commissions related to the Sales Agreement. We may terminate this at-the-market program at any time, pursuant to its terms. Uncertainties The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional 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 and extensive compliance-reporting capabilities. 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. Liquidity The Company expects that its operating losses and negative cash flows will continue for the foreseeable future. As of the issuance date of these consolidated financial statements, the Company expects that its cash, cash equivalents, marketable securities and restricted cash will be sufficient to fund its operating expenses and capital expenditure requirements through at least twelve months from the issuance date of these consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies and Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of significant accounting policies and recent accounting pronouncements	2. Summary of significant accounting policies and recent accounting pronouncements Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP), and include the accounts of Stoke Therapeutics, Inc. and its wholly-owned subsidiary. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). All intercompany transactions between and among the Company and its consolidated subsidiary have been eliminated. Use of estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, expenses and disclosure of contingent assets and liabilities. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates. Cash and cash equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits its cash in checking, sweep and money market accounts. Restricted cash At December 31, 2022, restricted cash consisted of money market accounts collateralizing letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. The following table reconciles cash and cash equivalents and restricted cash per the consolidated balance sheets to the statement of cash flows: As of December 31, 2022 2021 Cash and cash equivalents $ 113,556 $ 144,895 Restricted cash 569 569 $ 114,125 $ 145,464 Marketable Securities Marketable securities consist of government securities and obligations, corporate bonds and commercial paper with original maturities of more than 90 days. Investments are classified as available-for-sale and are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of other comprehensive income/(loss). Management determines the appropriate classification of its investments at the time of purchase and reevaluates such determination at each balance sheet date. Concentration of credit risk Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash and cash equivalents. The Company maintains its cash and cash equivalents at an accredited financial institution in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Fair value of financial instruments ASC Topic 820, Fair Value Measurement Level 1—Quoted market prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Revenue recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers In January 2022, the Company entered into a collaboration and licensing agreement with Acadia Pharmaceuticals, Inc. (“Acadia”) which is within the scope of ASC 606 (see Note 8). In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under this agreement, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for this arrangement, the Company must use its judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above; (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above; and (d) the contract term and pattern of satisfaction of the performance obligations under step (v) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts due to the Company for satisfying the revenue recognition criteria or that are contractually due based upon the terms of the collaboration agreements are recorded as accounts receivable in the Company’s consolidated balance sheets. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Upfront license fees The licenses of the Company’s intellectual property granted to Acadia was not determined to be distinct from the other promises or performance obligations identified in the arrangement. Accordingly, such licenses are therefore combined with other promises in the arrangement. The Company exercises judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. No such material rights were identified in the arrangement with Acadia. If such material rights were identified, then the Company would allocate the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized or begin to be recognized as revenue until, at the earliest, the option is exercised. Research and development services The promises under the Company’s collaboration agreement with Acadia includes research and development services to be performed by the Company for or on behalf of the customer. Payments or reimbursements resulting from the Company’s research and development efforts are recognized as the services are performed and presented on a gross basis because the Company is the principal for such efforts. Milestone payments At the inception of the Acadia arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone in making this assessment. There is judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. The development milestones in the Acadia arrangement are not considered probable of achievement at the outset of the arrangement. Deferred offering costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in the consolidated statement of stockholders’ equity as a reduction of additional paid-in capital. Property and equipment Property and equipment are recorded at cost less accumulated depreciation. Cost includes the acquisition costs and all costs necessary to bring the asset to the location and working condition necessary for its intended use. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the accompanying consolidated statements of operations and comprehensive loss. Expenditures for normal, recurring or periodic repairs and maintenance related to property and equipment are charged to expense as incurred. The cost for planned major maintenance activities, including the related acquisition or construction of assets, is capitalized if it will result in future economic benefits. Estimated useful lives for property and equipment are as follows: Property and equipment Estimated useful life Computer and office equipment 3-5 years Laboratory equipment and Furniture and fixtures 5-7 years Leasehold improvements Lesser of estimated useful life or remaining lease term Impairment of long-lived assets The Company reviews the recoverability of its long-lived assets when events or changes in circumstances occur that indicate that the carrying value of the assets may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest expense) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There were no impairment losses recognized during the years ended December 31, 2022 and 2021. Research and development costs Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, depreciation, third-party license fees, and costs related to third parties engaged to conduct preclinical research development activities. The Company has entered into various research and development contracts with research institutions and other companies to conduct research on its behalf. These agreements are generally cancellable. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. Stock options The Company measures its stock-based awards granted based on the estimated fair values of the awards and recognizes the compensation for employees and nonemployees over the requisite service period. The Company uses the Black-Scholes option-pricing model to estimate the fair value of its stock-based awards. The Company has elected the practical expedient to use the midpoint between vesting date and the contractual term as the expected term for certain awards with service or performance conditions. Stock-based compensation is recognized using the straight-line method. Forfeitures of unvested stock-based awards are accounted for when they occur. Patent costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss. Income The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the estimated future tax consequences attributable to temporary differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax base. Deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the temporary differences are expected to be settled or recovered. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. At December 31, 2022 and 2021, the Company has recorded a full valuation allowance. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more-likely-than-not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. Interest and penalties related to uncertain tax positions are recognized in the provision of income taxes; however, the Company currently has no interest or penalties related to uncertain income tax benefits. Segment and geographic information Operating segments are defined as components of an entity about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company operates in one segment in the United States. The Company’s chief executive officer, as the chief operating decision-maker, manages and allocates resources to the operations of the Company on a total company basis using consolidated financial information. Emerging growth company and smaller reporting company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the JOBS Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, the Company’s consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. The Company will remain an emerging growth company until the earliest of (i) the last day of its first fiscal year (a) in which the Company has total annual gross revenues of at least $1.07 billion or (b) in which the Company is deemed to be a large accelerated filer, which means the market value of the Company’s common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30 th The Company is also a “smaller reporting company,” meaning that in the event of an initial public offering the market value of its stock held by non-affiliates plus the proposed aggregate amount of gross proceeds to the Company as a result of such offering is less than $700 million and its annual revenue is less than $100 million during the most recently completed fiscal year. The Company may continue to be a smaller reporting company as long as either (i) the market value of its stock held by non-affiliates is less than $250 million or (ii) its annual revenue is less than $100 million during the most recently completed fiscal year and the market value of its stock held by non-affiliates is less than $700 million. If the Company is a smaller reporting company at the time it ceases to be an emerging growth company, the Company may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, the Company may choose to present only the two most recent fiscal years of audited financial statements in its Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation. Recently issued accounting pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This guidance removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This ASU is effective for interim and annual periods beginning after December 15, 2020, and early adoption is permitted. The Company adopted this standard on January 1, 2021 and the adoption of this update did not have a material impact on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value measurements	3. Fair value measurements The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair value measurements as of December 31, 2022 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 111,927 $ — $ — $ 111,927 Total $ 111,927 $ — $ — $ 111,927 Marketable Securities: Corporate bonds $ — $ 34,527 $ — $ 34,527 Commercial paper $ — $ 7,978 $ — $ 7,978 US Government debt securities $ — $ 73,534 $ — $ 73,534 Total $ — $ 116,039 $ — $ 116,039 Fair value measurements as of December 31, 2021 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 144,897 $ — $ — $ 144,897 Total $ 144,897 $ — $ — $ 144,897 Marketable Securities: Corporate bonds $ — $ 17,524 $ — $ 17,524 Commercial paper $ — $ 27,487 $ — $ 27,487 US Government debt securities $ — $ 29,904 $ — $ 29,904 Total $ — $ 74,915 $ — $ 74,915 The Company’s cash equivalents and marketable securities are carried at fair value, determined according to the fair value hierarchy described above and in Note 2. The carrying value of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities. The Company’s assets with fair value categorized as Level 1 within the fair value hierarchy include money market funds. Money market funds are publicly traded mutual funds and are presented as cash equivalents on the consolidated balance sheets as of December 31, 2022 and December 31, 2021. The Company measures its marketable securities at fair value on a recurring basis and classifies those instruments within Level 2 of the fair value hierarchy. There were no transfers to Level 3 in the periods presented.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2022
Investments Debt And Equity Securities [Abstract]
Marketable Securities	4. Marketable Securities The following table summarizes the Company’s marketable securities as of December 31, 2022 (in thousands): December 31, 2022 Amortized Cost Unrealized Gains Unrealized Loss Fair Value Marketable securities: Corporate bonds $ 34,662 $ — $ (135 ) $ 34,527 Commercial paper $ 8,019 $ — $ (41 ) $ 7,978 US Government debt securities $ 74,533 $ — $ (999 ) $ 73,534 Total $ 117,214 $ — $ (1,175 ) $ 116,039 The following table summarizes the Company’s marketable securities as of December 31, 2021 (in thousands): December 31, 2021 Amortized Cost Unrealized Gains Unrealized Loss Fair Value Marketable securities: Corporate bonds $ 17,598 $ — $ (74 ) $ 17,524 Commercial paper $ 27,487 $ — $ — $ 27,487 US Government debt securities $ 29,998 $ — $ (94 ) $ 29,904 Total $ 75,083 $ — $ (168 ) $ 74,915 The weighted average maturity of the Company’s marketable securities as of December 31, 2022 ranges from approximately 0.184 years to 0.489 years. The Company did not record an allowance for credit losses as of December 31, 2022 related to our marketable securities. Further, given the lack of significant change in the credit risk of these investments, the Company did not recognize any other-than-temporary impairment losses.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2022
Property Plant And Equipment [Abstract]
Property and equipment, net	5. Property and equipment, net Property and equipment, net consisted of the following: As of December 31, 2022 2021 Laboratory equipment $ 7,903 $ 4,670 Furniture and fixtures 312 153 Leasehold improvements 1,867 263 Office equipment 353 108 Construction in progress 447 1,606 10,882 6,800 Less accumulated depreciation (4,207 ) (2,661 ) $ 6,675 $ 4,139 Depreciation expense was $1.5 million and $1.0 million for the years ended December 31, 2022 and 2021, respectively.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	12 Months Ended
	Dec. 31, 2022
Payables And Accruals [Abstract]
Accrued and other current liabilities	6. Accrued and other current liabilities Accrued and other current liabilities consisted of the following: As of December 31, 2022 2021 Accrued employee compensation costs $ 5,754 $ 5,383 Accrued professional 525 523 Accrued research and development costs 6,601 6,801 Current portion of operating lease liabilities 2,359 1,507 Other current liabilities 509 540 $ 15,748 $ 14,754

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	7. Operating lease The Company determines whether an arrangement is a lease at inception. The Company accounts for a lease when it has the right to control the leased asset for a period of time while obtaining substantially all of the assets’ economic benefits. Operating lease right-of-use assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the lease commencement date. The discount rate used to determine the present value of the lease payments is the Company’s incremental borrowing rate based on the information available at lease inception, as the Company did not have information to determine the rate implicit in the leases. Lease expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments (which include initial direct costs and lease incentives). The expense is included in operating expenses in the consolidated statements of operations and comprehensive loss. The Company’s lease agreements also contain variable payments, primarily maintenance-related costs, which are expensed as incurred and not included in the measurement of the right-of-use assets and lease liabilities. In August 2018, the Company entered into an agreement to lease approximately 23,000 square feet of space for a term of three years. Lease terms are triple net lease commencing at $0.9 million per year, then with 3% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. The lease commencement date was December 10, 2018. In September 2021, the Company entered into an agreement to extend the initial term of the 23,000 square foot lease for a period of three years commencing on December 15, 2021 and ending December 31, 2024. In addition, this lease provides for the lease of an additional 15,000 square feet of rentable space beginning on April 1, 2022 and ending on December 31, 2024. In December 2021, the Company recognized a right-of-use asset and operating lease liability of $3.5 million for the 23,000 square feet. On April 1, 2022, the Company recognized a right-of-use asset and operating lease liability of $1.8 million for the 15,000 square feet. In December 2018, the Company entered into an agreement to lease 2,485 square feet of space for an initial term of three years. The lease includes one renewal option for an additional two years, however, any time after the initial term the landlord may relocate the Company from the premises to a space reasonably comparable in size and utility. As the Company does not have the right to control the use of the identified asset after the initial term, the renewal option was excluded from the lease liability calculation. Lease terms commence at $0.2 million per annum, with 2.5% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. The lease commencement date was May 1, 2019. In June 2021, the Company amended the agreement to extend the initial term of the 2,485 square foot lease for a period of three years commencing May 1, 2022 and ending April 30, 2025. In addition, the amendment provided for the lease of an additional 2,357 square feet of rentable space beginning on July 6, 2021 and ending on April 30, 2025. The amended lease provides the Company with the option to extend the term of the lease for an additional two years. In 2021, the Company recognized a right-of-use asset and operating lease liabilities of $0.7 million for the extension of the lease to April 30, 2025 and a right-of-use asset and operating lease liabilities of $0.8 million for the additional 2,357 square feet of rentable space. Future minimum lease payments under non-cancellable leases as of December 31, 2022, are as follows (in thousands): 2023 $ 2,532 2024 2,608 2025 173 Total lease payments $ 5,313 Less imputed interest (237 ) Present value of lease liabilities $ 5,076 Lease balances as of December 31, 2022 and December 31, 2021 are as follows (in thousands): As of December 31, 2022 2021 Operating right-of-use assets $ 4,753 $ 4,939 Current portion of operating lease liabilities $ 2,359 $ 1,507 Non-current portion of operating lease liabilities 2,717 3,532 Total operating lease liabilities $ 5,076 $ 5,039 The weighted average remaining lease term and weighted average discount rate of our operating leases as of December 31, 2022 are as follows: Weighted average remaining lease term in years 2.1 Weighted average discount rate 4.69 % In accordance with Topic 842, lease expense incurred under operating leases was approximately $2.2 million for the year ended December 31, 2022, and $1.4 million for the year ended December 31, 2021. Scientific Advisory Board Agreement In June 2020, the Company entered into a scientific advisory board agreement with a member of the Company’s board of directors, who is also an employee of Cold Spring Harbor Laboratory (“CSHL”), to provide scientific advisory services related to the Company’s Targeted Augmentation of Nuclear Gene Output (“TANGO”) antisense oligonucleotide technology and other antisense oligonucleotide technologies, as well as current and future therapeutic targets and programs. Following the expiration of the initial scientific agreement in June 2021 and a renewal agreement in June 2022, the parties entered into subsequent scientific board agreements on substantially the same terms. The Company recognized expense of $0.02 million for the year ended December 31, 2022 and $0.05 million for the year ended December 31, 2021 for such scientific advisory services. The term of the renewal agreement is 12 months. License and research agreements In July 2015, the Company entered into a worldwide license agreement, or the CSHL Agreement, with CSHL, with respect to TANGO patents. Under the CSHL Agreement, the Company receives an exclusive (except with respect to certain government rights and non-exclusive licenses), worldwide license under certain patents and applications relating to TANGO. The CSHL Agreement obligates the Company to make payments that are contingent upon certain milestones being achieved. The Company is also required to pay royalties, tiered based on the scope of patent coverage for each licensed product, ranging from a low-single digit percentage to a mid-single digit percentage on annual net sales. These royalty obligations apply on a licensed product-by-licensed product and country-by-country basis until the latest of (i) the expiration of the last valid claim of a CSHL patent covering the applicable licensed product or (ii) the expiration of any regulatory exclusivity for the applicable licensed product. In addition, if the Company sublicenses the rights under the CSHL Agreement, it is required to pay a maximum of twenty percent of the sublicense revenue to CSHL, which may be reduced to a mid-teens or a mid-single digit percentage upon achievement of certain clinical milestones for the applicable licensed product. Finally, the Company is required to pay an annual license maintenance fee of $0.01 million, which amount is creditable against any owed royalty or milestone payments. The maximum aggregate potential milestone payments payable total approximately $0.9 million. Additionally, certain licenses under the CSHL Agreement require the Company to reimburse CSHL for certain past and ongoing patent related expenses, however there were no expenses related to these reimbursable patent costs during the years ended December 31, 2022 and 2021. In February 2023, the Company delivered a notice of termination of the CSHL Agreement to CSHL, and the Company expects the CSHL Agreement to be terminated within 90 days of such notice. The Company does not expect the termination of the CSHL Agreement to have a significant impact on the intellectual property underlying any of its current product candidates, including STK-001 and STK-002, or its continued development of the TANGO platform. In April 2016, the Company entered into an exclusive, worldwide license agreement with the University of Southampton (the “Southampton Agreement”), whereby the Company acquired rights to foundational technologies related to the Company’s TANGO technology. Under the Southampton Agreement, the Company receives an exclusive, worldwide license under certain licensed patents and applications relating to TANGO. Under the Southampton Agreement, the Company may be obligated to make additional payments that are contingent upon certain milestones being achieved, as well as royalties on future product sales. These royalty obligations survive until the latest of (i) the expiration of the last valid claim of a licensed patent covering a subject product or (ii) the expiration of any regulatory exclusivity for the subject product in a country. In addition, if the Company sublicenses its rights under the Southampton Agreement, the Company is required to pay a mid-single digit percentage of the sublicense revenue to the University of Southampton. As of December 31, 2022, the Company had paid $0.7 million under the Southampton Agreement as a result of entering into the Acadia Pharmaceuticals Inc. license and collaboration agreement in January 2022 (see Note 8). Additionally, certain licenses under the Southampton Agreement require the Company to reimburse the University of Southampton for certain past and ongoing patent related expenses. For the year ended December 31, 2022 these expenses were $0.02 million compared to $0.12 million for the year ended December 31, 2021. Litigation The Company may periodically become subject to legal proceedings and claims arising in connection with ongoing business activities, including claims or disputes related to patents that have been issued or that are pending in the field of research on which it is focused. As of December 31, 2022, the Company had no legal proceedings to which it was a party or to which its property was subject that, in the opinion of management, would have a material adverse effect on its business.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	9. Share-Based Compensation In June 2019, the Company’s board of directors and stockholders approved the 2019 Equity Incentive Plan (the “2019 Plan”) which became effective on June 17, 2019 and replaced the Company’s 2014 Equity Incentive Plan (the “2014 Plan”). In addition to the shares of common stock reserved for future issuance under the 2014 Plan that were added to the 2019 Plan upon its effective date, the Company initially reserved 2,200,000 shares of common stock for issuance under the 2019 Plan. The number of shares reserved for issuance under the Company’s 2019 Plan will increase automatically on January 1 of each of 2020 through 2029 by the number of shares equal to 4% of the aggregate number of outstanding shares of the Company’s common stock as of the immediately preceding December 31, or a lesser number as may be determined by the Company’s board of directors. As of December 31, 2022 there were no shares available for future issuance under the 2014 Plan and 992,231 shares were available for future issuance under the 2019 Plan. During the years ended December 31, 2022 and December 31, 2021, the Company granted options to purchase 3,459,500 and 1,311,897 shares of common stock to certain of its employees, and directors, respectively. The options vest up to four years except for certain options granted to members of our board of directors which vest over one or three years and are exercisable at a per share price equal to the fair value of the common stock on the grant date. A summary of stock option activity for awards is presented below: Number of shares Weighted average exercise price Weighted average remaining contractual life (years) Aggregate intrinsic value (1) Outstanding as of December 31, 2021 5,435,304 $ 19.77 8.0 $ 64,981 Granted 3,459,500 15.97 Exercised (270,376 ) 1.83 Forfeitures (254,450 ) 29.77 Expired (95,331 ) 34.72 Outstanding as of December 31, 2022 8,274,647 $ 18.28 7.6 $ 20,598 Exercisable as of December 31, 2022 4,286,461 $ 14.70 6.4 $ 18,454 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at December 31, 2022 and 2021. The weighted average grant date fair value per share of stock options granted during the years ended December 31, 2022 and 2021 was $10.32 and $34.07, respectively. The aggregate grant date fair value of stock options granted during the years ended December 31, 2022 and 2021 was approximately $35.7 million and $44.7 million, respectively. The aggregate intrinsic value of stock options exercised during the year ended December 31, 2022 and 2021 was approximately $3.5 million and $9.9 million, respectively. Stock-based compensation and stock options The Company recorded stock-based compensation expense of $22.9 million and $16.5 million during the years ended December 31, 2022 and 2021, respectively. As of December 31, 2022, there was $53.3 million of unrecognized compensation cost related to unvested stock-based compensation arrangements granted under the 2014 and the 2019 Plans. The compensation is expected to be recognized over a weighted average period of 2.8 years as of December 31, 2022. Stock-based compensation expense recorded as research and development and general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss is as follows: Year ended December 31, 2022 2021 Research and development $ 8,901 $ 6,215 General and administrative 13,953 10,235 $ 22,854 $ 16,450 The Company uses the Black-Scholes option pricing model to calculate the grant-date fair value of an award. The fair values of the options granted to employees and directors were calculated using the following assumptions for the years ended December 31, 2022 and 2021: Year ended December 31, 2022 2021 Risk-free interest rate 1.82-4.15% 0.78-1.51% Expected dividend yield 0% 0% Expected life 5.5-6.25 years 5.5-6.25 years Expected volatility 70-71% 70-73% 2019 Employee stock purchase plan In June 2019, the Company adopted the 2019 Employee Stock Purchase Plan (“ESPP”), which became effective on June 18, 2019. The Company initially reserved 315,000 shares of common stock for sale under the ESPP. At December 31, 2022, the Company had 959,603 shares available for issuance under the plan. The average grant date fair value per share under the plan was $18.39 for 2022. The total ESPP stock-based compensation expense for the year ended December 31, 2022 was $0.3 million and for the year ended December 31, 2021 was $0.3 million. The number of shares reserved for issuance under the ESPP will increase automatically on January 1st of each of the first ten calendar years following the first offering date by the number of shares equal to the lesser of 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31 or a lower amount determined by the Company’s board of directors. The aggregate number of shares issued over the term of the ESPP will not exceed 3,150,000 shares of the Company’s common stock.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net loss per share	10. Net loss per share The following table summarizes the computation of basic and diluted net loss per share of the Company: Year ended December 31, 2022 2021 Numerator: Net loss $ (101,067 ) $ (85,805 ) Denominator: Weighted-average number of common shares, basic and diluted 38,897,442 36,739,269 Net loss per share, basic and diluted $ (2.60 ) $ (2.34 ) The Company’s potential dilutive securities, which include common stock options and ESPP purchase rights, have been excluded from the computation of diluted net loss per share as the effect would be anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: December 31, 2022 2021 Outstanding options to purchase common stock 8,274,647 5,435,304

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income taxes	11. Income taxes A reconciliation of the expected income tax expense (benefit) computed using the federal statutory income tax rate the Company’s effective income tax rate is as follows: Year ended December 31, 2022 2021 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 7.4 7.9 Non-deductible items (0.9 ) 0.4 Research and development credit, net 3.9 4.1 Other 0.1 0.0 Change in valuation allowance (31.5 ) (33.4 ) Total 0.0 % 0.0 % The principal components of the Company’s deferred tax assets and liabilities consist of the following: As of December 31, 2022 2021 Deferred tax assets: Federal and state net operating loss carryforwards $ 57,746 $ 52,231 Research and development tax credits 12,613 7,726 R&D capitalized expenses 17,148 — Accrued compensation and stock compensation 10,274 6,055 Other 142 20 Gross deferred tax assets 97,923 66,032 Less: valuation allowance (97,923 ) (66,032 ) Net deferred tax assets $ — $ — As of December 31, 2022 and 2021, the Company had federal net operating loss carryforwards of $210.9 million and $191.1 million, respectively, which may be available to reduce future taxable income, and expire at various dates beginning in 2034, for those net operating loss carryforwards generated prior to 2018. Net operating losses generated in 2018 and beyond have no expiration. As of December 31, 2022 and 2021, the Company had state net operating loss carry forwards of $212.8 million and $191.4 million, respectively, which may be available to reduce future taxable income and expire at various dates beginning in 2035. In addition, at December 31, 2022 and 2021, the Company had federal research and development tax credit carryforwards of $9.2 million and $5.4 million, respectively, and state research and development tax credit carry forwards of $4.3 million and $3.0 million, respectively. Both federal and state research and development tax credit carry forwards may be available to reduce future tax liabilities and expire at various dates beginning in 2030. In accordance with ASC 740, Accounting for Income Taxes, management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards. Management has determined that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets and, as a result, a full valuation allowance of $97.9 million and $66.0 million was established at December 31, 2022 and 2021, respectively. The change in the valuation allowance was an increase of $31.8 million and $28.8 million in 2022 and 2021, respectively. Effective for tax years beginning after December 31, 2021, the Tax Cuts and Jobs Act of 2017 requires companies to capitalize and amortize domestic research and development expenditures over five years for tax purposes, and foreign research and development expenditures over fifteen years for tax purposes. We will continue to monitor any potential changes or further guidance related to this provision. On August 16, 2022, President Biden signed the Inflation Reduction Act of 2022 into law which contained provisions that include a 15% corporate minimum tax effective for taxable years beginning after December 31, 2022 and a 1% excise tax on certain stock buybacks after December 31, 2022. The Company expects the impact of these provisions to be immaterial. Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the Code) due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income. The Company has not conducted a formal study to assess whether a change of control has occurred or whether there have been multiple changes of control since inception due to the significant complexity and cost associated with such a study. If the Company has experienced a change of control, as defined for purposes of Section 382 and 383 of the Code, at any time since inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards may be subject to an annual limitation under Section 382 and 383 of the Code, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate, and then could be subject to additional adjustments, as required. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research and development tax credit carryforwards before utilization. The Company applies ASC 740 related to accounting for uncertainty in income taxes. The Company’s reserves related to income taxes are based on a determination of whether, and how much of, a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. At December 31, 2022, and 2021 the Company had no unrecognized tax benefits. Interest and penalty charges, if any, related to unrecognized tax benefits would be classified as income tax expense in the accompanying consolidated statements of operations and comprehensive loss.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2022
Compensation And Retirement Disclosure [Abstract]
Employee benefits	12. Employee benefits In 2016, the Company established a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis. The Company matches contributions up to 4% of annual salary for those employees who are participating in the 401(k) Plan. For the year ended December 31, 2022, the Company made matching contributions of $0.6 million and for the year ended December 31, 2021, the Company made matching contributions of $0.5 million.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent events	13. Subsequent events Since December 31, 2022, we sold approximately 4.6 million shares of our common stock and received $44.7 million after deducting commissions related to the Sales Agreement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Recent Accounting Pronouncements (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP), and include the accounts of Stoke Therapeutics, Inc. and its wholly-owned subsidiary. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). All intercompany transactions between and among the Company and its consolidated subsidiary have been eliminated.
Use of Estimates	Use of estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, expenses and disclosure of contingent assets and liabilities. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and cash equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits its cash in checking, sweep and money market accounts.
Restricted Cash	Restricted cash At December 31, 2022, restricted cash consisted of money market accounts collateralizing letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities. The following table reconciles cash and cash equivalents and restricted cash per the consolidated balance sheets to the statement of cash flows: As of December 31, 2022 2021 Cash and cash equivalents $ 113,556 $ 144,895 Restricted cash 569 569 $ 114,125 $ 145,464
Marketable Securities	Marketable Securities Marketable securities consist of government securities and obligations, corporate bonds and commercial paper with original maturities of more than 90 days. Investments are classified as available-for-sale and are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of other comprehensive income/(loss). Management determines the appropriate classification of its investments at the time of purchase and reevaluates such determination at each balance sheet date.
Concentration of Credit Risk	Concentration of credit risk Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash and cash equivalents. The Company maintains its cash and cash equivalents at an accredited financial institution in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.
Fair Value of Financial Instruments	Fair value of financial instruments ASC Topic 820, Fair Value Measurement Level 1—Quoted market prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
Revenue Recognition	Revenue recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers In January 2022, the Company entered into a collaboration and licensing agreement with Acadia Pharmaceuticals, Inc. (“Acadia”) which is within the scope of ASC 606 (see Note 8). In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under this agreement, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for this arrangement, the Company must use its judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above; (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above; and (d) the contract term and pattern of satisfaction of the performance obligations under step (v) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts due to the Company for satisfying the revenue recognition criteria or that are contractually due based upon the terms of the collaboration agreements are recorded as accounts receivable in the Company’s consolidated balance sheets. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Upfront license fees The licenses of the Company’s intellectual property granted to Acadia was not determined to be distinct from the other promises or performance obligations identified in the arrangement. Accordingly, such licenses are therefore combined with other promises in the arrangement. The Company exercises judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. No such material rights were identified in the arrangement with Acadia. If such material rights were identified, then the Company would allocate the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized or begin to be recognized as revenue until, at the earliest, the option is exercised. Research and development services The promises under the Company’s collaboration agreement with Acadia includes research and development services to be performed by the Company for or on behalf of the customer. Payments or reimbursements resulting from the Company’s research and development efforts are recognized as the services are performed and presented on a gross basis because the Company is the principal for such efforts. Milestone payments At the inception of the Acadia arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone in making this assessment. There is judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. The development milestones in the Acadia arrangement are not considered probable of achievement at the outset of the arrangement.
Deferred Offering Costs	Deferred offering costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in the consolidated statement of stockholders’ equity as a reduction of additional paid-in capital.
Property and Equipment	Property and equipment Property and equipment are recorded at cost less accumulated depreciation. Cost includes the acquisition costs and all costs necessary to bring the asset to the location and working condition necessary for its intended use. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the accompanying consolidated statements of operations and comprehensive loss. Expenditures for normal, recurring or periodic repairs and maintenance related to property and equipment are charged to expense as incurred. The cost for planned major maintenance activities, including the related acquisition or construction of assets, is capitalized if it will result in future economic benefits. Estimated useful lives for property and equipment are as follows: Property and equipment Estimated useful life Computer and office equipment 3-5 years Laboratory equipment and Furniture and fixtures 5-7 years Leasehold improvements Lesser of estimated useful life or remaining lease term
Impairment of Long-Lived Assets	Impairment of long-lived assets The Company reviews the recoverability of its long-lived assets when events or changes in circumstances occur that indicate that the carrying value of the assets may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest expense) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There were no impairment losses recognized during the years ended December 31, 2022 and 2021.
Research and Development Costs	Research and development costs Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, depreciation, third-party license fees, and costs related to third parties engaged to conduct preclinical research development activities. The Company has entered into various research and development contracts with research institutions and other companies to conduct research on its behalf. These agreements are generally cancellable. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.
Stock Options	Stock options The Company measures its stock-based awards granted based on the estimated fair values of the awards and recognizes the compensation for employees and nonemployees over the requisite service period. The Company uses the Black-Scholes option-pricing model to estimate the fair value of its stock-based awards. The Company has elected the practical expedient to use the midpoint between vesting date and the contractual term as the expected term for certain awards with service or performance conditions. Stock-based compensation is recognized using the straight-line method. Forfeitures of unvested stock-based awards are accounted for when they occur.
Patent Costs	Patent costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss.
Income Taxes	Income The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the estimated future tax consequences attributable to temporary differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax base. Deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the temporary differences are expected to be settled or recovered. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. At December 31, 2022 and 2021, the Company has recorded a full valuation allowance. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more-likely-than-not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. Interest and penalties related to uncertain tax positions are recognized in the provision of income taxes; however, the Company currently has no interest or penalties related to uncertain income tax benefits.
Segment and Geographic Information	Segment and geographic information Operating segments are defined as components of an entity about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company operates in one segment in the United States. The Company’s chief executive officer, as the chief operating decision-maker, manages and allocates resources to the operations of the Company on a total company basis using consolidated financial information.
Emerging Growth Company and Smaller Reporting Company Status	Emerging growth company and smaller reporting company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the JOBS Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, the Company’s consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. The Company will remain an emerging growth company until the earliest of (i) the last day of its first fiscal year (a) in which the Company has total annual gross revenues of at least $1.07 billion or (b) in which the Company is deemed to be a large accelerated filer, which means the market value of the Company’s common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30 th The Company is also a “smaller reporting company,” meaning that in the event of an initial public offering the market value of its stock held by non-affiliates plus the proposed aggregate amount of gross proceeds to the Company as a result of such offering is less than $700 million and its annual revenue is less than $100 million during the most recently completed fiscal year. The Company may continue to be a smaller reporting company as long as either (i) the market value of its stock held by non-affiliates is less than $250 million or (ii) its annual revenue is less than $100 million during the most recently completed fiscal year and the market value of its stock held by non-affiliates is less than $700 million. If the Company is a smaller reporting company at the time it ceases to be an emerging growth company, the Company may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, the Company may choose to present only the two most recent fiscal years of audited financial statements in its Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.
Recently Issued Accounting Pronouncements	Recently issued accounting pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This guidance removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This ASU is effective for interim and annual periods beginning after December 15, 2020, and early adoption is permitted. The Company adopted this standard on January 1, 2021 and the adoption of this update did not have a material impact on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of Cash and Cash Equivalents and Restricted Cash	The following table reconciles cash and cash equivalents and restricted cash per the consolidated balance sheets to the statement of cash flows: As of December 31, 2022 2021 Cash and cash equivalents $ 113,556 $ 144,895 Restricted cash 569 569 $ 114,125 $ 145,464
Schedule of Estimated Useful Lives for Property and Equipment	Estimated useful lives for property and equipment are as follows: Property and equipment Estimated useful life Computer and office equipment 3-5 years Laboratory equipment and Furniture and fixtures 5-7 years Leasehold improvements Lesser of estimated useful life or remaining lease term

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value on Recurring Basis and Level of Fair Value Hierarchy Utilized	The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair value measurements as of December 31, 2022 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 111,927 $ — $ — $ 111,927 Total $ 111,927 $ — $ — $ 111,927 Marketable Securities: Corporate bonds $ — $ 34,527 $ — $ 34,527 Commercial paper $ — $ 7,978 $ — $ 7,978 US Government debt securities $ — $ 73,534 $ — $ 73,534 Total $ — $ 116,039 $ — $ 116,039 Fair value measurements as of December 31, 2021 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 144,897 $ — $ — $ 144,897 Total $ 144,897 $ — $ — $ 144,897 Marketable Securities: Corporate bonds $ — $ 17,524 $ — $ 17,524 Commercial paper $ — $ 27,487 $ — $ 27,487 US Government debt securities $ — $ 29,904 $ — $ 29,904 Total $ — $ 74,915 $ — $ 74,915

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments Debt And Equity Securities [Abstract]
Summary of Marketable Securities	The following table summarizes the Company’s marketable securities as of December 31, 2022 (in thousands): December 31, 2022 Amortized Cost Unrealized Gains Unrealized Loss Fair Value Marketable securities: Corporate bonds $ 34,662 $ — $ (135 ) $ 34,527 Commercial paper $ 8,019 $ — $ (41 ) $ 7,978 US Government debt securities $ 74,533 $ — $ (999 ) $ 73,534 Total $ 117,214 $ — $ (1,175 ) $ 116,039 The following table summarizes the Company’s marketable securities as of December 31, 2021 (in thousands): December 31, 2021 Amortized Cost Unrealized Gains Unrealized Loss Fair Value Marketable securities: Corporate bonds $ 17,598 $ — $ (74 ) $ 17,524 Commercial paper $ 27,487 $ — $ — $ 27,487 US Government debt securities $ 29,998 $ — $ (94 ) $ 29,904 Total $ 75,083 $ — $ (168 ) $ 74,915

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Property Plant And Equipment [Abstract]
Summary of Property, and Equipment, Net	Property and equipment, net consisted of the following: As of December 31, 2022 2021 Laboratory equipment $ 7,903 $ 4,670 Furniture and fixtures 312 153 Leasehold improvements 1,867 263 Office equipment 353 108 Construction in progress 447 1,606 10,882 6,800 Less accumulated depreciation (4,207 ) (2,661 ) $ 6,675 $ 4,139

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Payables And Accruals [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following: As of December 31, 2022 2021 Accrued employee compensation costs $ 5,754 $ 5,383 Accrued professional 525 523 Accrued research and development costs 6,601 6,801 Current portion of operating lease liabilities 2,359 1,507 Other current liabilities 509 540 $ 15,748 $ 14,754

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments Under Non-Cancellable Leases	Future minimum lease payments under non-cancellable leases as of December 31, 2022, are as follows (in thousands): 2023 $ 2,532 2024 2,608 2025 173 Total lease payments $ 5,313 Less imputed interest (237 ) Present value of lease liabilities $ 5,076
Summary of Lease Balances	Lease balances as of December 31, 2022 and December 31, 2021 are as follows (in thousands): As of December 31, 2022 2021 Operating right-of-use assets $ 4,753 $ 4,939 Current portion of operating lease liabilities $ 2,359 $ 1,507 Non-current portion of operating lease liabilities 2,717 3,532 Total operating lease liabilities $ 5,076 $ 5,039
Summary of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Operating Leases	The weighted average remaining lease term and weighted average discount rate of our operating leases as of December 31, 2022 are as follows: Weighted average remaining lease term in years 2.1 Weighted average discount rate 4.69 %

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity for Awards	A summary of stock option activity for awards is presented below: Number of shares Weighted average exercise price Weighted average remaining contractual life (years) Aggregate intrinsic value (1) Outstanding as of December 31, 2021 5,435,304 $ 19.77 8.0 $ 64,981 Granted 3,459,500 15.97 Exercised (270,376 ) 1.83 Forfeitures (254,450 ) 29.77 Expired (95,331 ) 34.72 Outstanding as of December 31, 2022 8,274,647 $ 18.28 7.6 $ 20,598 Exercisable as of December 31, 2022 4,286,461 $ 14.70 6.4 $ 18,454
Summary of Stock-based Compensation Expense	Stock-based compensation expense recorded as research and development and general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss is as follows: Year ended December 31, 2022 2021 Research and development $ 8,901 $ 6,215 General and administrative 13,953 10,235 $ 22,854 $ 16,450
Summary of Fair Values of Options Granted to Employees and Directors	The Company uses the Black-Scholes option pricing model to calculate the grant-date fair value of an award. The fair values of the options granted to employees and directors were calculated using the following assumptions for the years ended December 31, 2022 and 2021: Year ended December 31, 2022 2021 Risk-free interest rate 1.82-4.15% 0.78-1.51% Expected dividend yield 0% 0% Expected life 5.5-6.25 years 5.5-6.25 years Expected volatility 70-71% 70-73%

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table summarizes the computation of basic and diluted net loss per share of the Company: Year ended December 31, 2022 2021 Numerator: Net loss $ (101,067 ) $ (85,805 ) Denominator: Weighted-average number of common shares, basic and diluted 38,897,442 36,739,269 Net loss per share, basic and diluted $ (2.60 ) $ (2.34 )
Schedule of Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The Company excluded the following potential common shares, presented based on amounts outstanding at period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: December 31, 2022 2021 Outstanding options to purchase common stock 8,274,647 5,435,304

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Reconciliation of Expected Income Tax Expense (Benefit) using Federal Statutory Income Tax Rate to Effective Income Tax Rate	A reconciliation of the expected income tax expense (benefit) computed using the federal statutory income tax rate the Company’s effective income tax rate is as follows: Year ended December 31, 2022 2021 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 7.4 7.9 Non-deductible items (0.9 ) 0.4 Research and development credit, net 3.9 4.1 Other 0.1 0.0 Change in valuation allowance (31.5 ) (33.4 ) Total 0.0 % 0.0 %
Schedule of Deferred Tax Assets and Liabilities	The principal components of the Company’s deferred tax assets and liabilities consist of the following: As of December 31, 2022 2021 Deferred tax assets: Federal and state net operating loss carryforwards $ 57,746 $ 52,231 Research and development tax credits 12,613 7,726 R&D capitalized expenses 17,148 — Accrued compensation and stock compensation 10,274 6,055 Other 142 20 Gross deferred tax assets 97,923 66,032 Less: valuation allowance (97,923 ) (66,032 ) Net deferred tax assets $ — $ —

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) - USD ($)	1 Months Ended			12 Months Ended
	Dec. 31, 2022	May 31, 2022	Jul. 31, 2020	Dec. 31, 2022
Nature Of Business And Basis Of Presentation [Line Items]
Entity incorporation state name				DE
Base Prospectus
Nature Of Business And Basis Of Presentation [Line Items]
Maximum aggregate offering price		$ 400,000,000	$ 400,000,000
Sales Agreement Prospectus
Nature Of Business And Basis Of Presentation [Line Items]
Maximum aggregate offering price		150,000,000	$ 150,000,000
Stock issued during period, shares	$ 4,600,000	2,200,000		$ 4,600,000
Proceeds from issuance of common stock net of commissions	$ 44,700,000	$ 45,300,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Schedule of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 113,556	$ 144,895
Restricted cash	569	569
Total cash, cash equivalents and restricted cash	$ 114,125	$ 145,464	$ 287,513

Summary of Significant Accoun_5

Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Schedule of Estimated Useful Lives for Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2022
Computer and Office Equipment | Minimum
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Computer and Office Equipment | Maximum
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Laboratory Equipment and Furniture and Fixtures | Minimum
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Laboratory Equipment and Furniture and Fixtures | Maximum
Property Plant And Equipment [Line Items]
Estimated useful life	7 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful life	Lesser of estimated useful life or remaining lease term

Summary of Significant Accoun_6

Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Accounting Policies [Line Items]
Impairment losses recognized	$ 0	$ 0
Unrecognized income tax benefits, interest or penalties	$ 0
Number of operating segments | Segment	1
ASU 2019-12
Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis and Level of Fair Value Hierarchy Utilized (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	$ 116,039	$ 74,915
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	34,527	17,524
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	7,978	27,487
US Government Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	73,534	29,904
Fair Value, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	111,927	144,897
Total Marketable Securities	116,039	74,915
Fair Value, Recurring | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	111,927	144,897
Fair Value, Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	111,927	144,897
Fair Value, Recurring | Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	111,927	144,897
Fair Value, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	116,039	74,915
Fair Value, Recurring | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	34,527	17,524
Fair Value, Recurring | Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	34,527	17,524
Fair Value, Recurring | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	7,978	27,487
Fair Value, Recurring | Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	7,978	27,487
Fair Value, Recurring | US Government Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	73,534	29,904
Fair Value, Recurring | US Government Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Marketable Securities	$ 73,534	$ 29,904

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair value assets, transfers to level 3, amount	$ 0	$ 0

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Marketable Securities, Amortized Cost	$ 117,214	$ 75,083
Marketable Securities, Unrealized Loss	(1,175)	(168)
Marketable Securities, Fair Value	116,039	74,915
Corporate Bonds
Marketable Securities [Line Items]
Marketable Securities, Amortized Cost	34,662	17,598
Marketable Securities, Unrealized Loss	(135)	(74)
Marketable Securities, Fair Value	34,527	17,524
Commercial Paper
Marketable Securities [Line Items]
Marketable Securities, Amortized Cost	8,019	27,487
Marketable Securities, Unrealized Loss	(41)
Marketable Securities, Fair Value	7,978	27,487
US Government Debt Securities
Marketable Securities [Line Items]
Marketable Securities, Amortized Cost	74,533	29,998
Marketable Securities, Unrealized Loss	(999)	(94)
Marketable Securities, Fair Value	$ 73,534	$ 29,904

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Marketable Securities [Line Items]
Allowance for credit losses	$ 0
Minimum
Marketable Securities [Line Items]
Weighted average maturity marketable securities period	2 months 6 days
Maximum
Marketable Securities [Line Items]
Weighted average maturity marketable securities period	5 months 26 days

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property, and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property, and equipment, gross	$ 10,882	$ 6,800
Less accumulated depreciation	(4,207)	(2,661)
Property, and equipment, net	6,675	4,139
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property, and equipment, gross	7,903	4,670
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, and equipment, gross	312	153
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, and equipment, gross	1,867	263
Office Equipment
Property Plant And Equipment [Line Items]
Property, and equipment, gross	353	108
Construction in Progress
Property Plant And Equipment [Line Items]
Property, and equipment, gross	$ 447	$ 1,606

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Depreciation	$ 1,546	$ 974

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued employee compensation costs	$ 5,754	$ 5,383
Accrued professional	525	523
Accrued research and development costs	6,601	6,801
Current portion of operating lease liabilities	2,359	1,507
Other current liabilities	509	540
Total accrued and other current liabilities	$ 15,748	$ 14,754

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	1 Months Ended					6 Months Ended	12 Months Ended
	Sep. 30, 2021 ft²	Jun. 30, 2021 ft²	Dec. 31, 2018 USD ($) ft² Option	Aug. 31, 2018 USD ($) ft²	Jul. 31, 2015	Jun. 30, 2022	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Apr. 01, 2022 USD ($)
Commitments And Contingencies [Line Items]
Area of space subject to operating lease | ft²			2,485	23,000
Operating lease term			3 years	3 years
Operating lease cost per year			$ 200,000	$ 900,000
Annual base rent increase percentage for operating lease			2.50%	3%
Operating lease commencement date			May 01, 2019	Dec. 10, 2018
Operating lease right-of-use assets							$ 4,753,000	$ 4,939,000
Operating lease liabilities							5,076,000
Number of options to renewal operating lease term | Option			1
Operating lease, renewal term			2 years
CSHL Agreement
Commitments And Contingencies [Line Items]
Percentage of maximum required payment of sublicense revenue					20%
Annual license maintenance fee							10,000
Maximum aggregate potential milestone payments payable							900,000
Expenses related to reimbursable patent costs							$ 0	0
CSHL agreement termination description							In February 2023, the Company delivered a notice of termination of the CSHL Agreement to CSHL, and the Company expects the CSHL Agreement to be terminated within 90 days of such notice.
Southampton Agreement
Commitments And Contingencies [Line Items]
Expenses related to reimbursable patent costs							$ 20,000	120,000
Payment for license and collaboration agreement							700,000
Member of Board of Directors
Commitments And Contingencies [Line Items]
Scientific advisory services expenses							20,000	50,000
Scientific advisory services agreement term						12 months
ASU 2016-02
Commitments And Contingencies [Line Items]
Operating leases expense							$ 2,200,000	1,400,000
Lease Commencement on December 15, 2021
Commitments And Contingencies [Line Items]
Area of space subject to operating lease | ft²	23,000
Operating lease term	3 years
Operating lease commencement date	Dec. 15, 2021
Operating lease expiration date	Dec. 31, 2024
Operating lease right-of-use assets								3,500,000
Operating lease liabilities								3,500,000
Lease Commencement on April 2022
Commitments And Contingencies [Line Items]
Area of space subject to operating lease | ft²	15,000
Operating lease commencement date	Apr. 01, 2022
Operating lease expiration date	Dec. 31, 2024
Operating lease right-of-use assets									$ 1,800,000
Operating lease liabilities									$ 1,800,000
Lease Extension End Date April 30, 2025
Commitments And Contingencies [Line Items]
Area of space subject to operating lease | ft²		2,485
Operating lease term		3 years
Operating lease commencement date		May 01, 2022
Operating lease expiration date		Apr. 30, 2025
Operating lease right-of-use assets								700,000
Operating lease liabilities								700,000
Operating lease, renewal term		2 years
Area of additional space subject to operating lease | ft²		2,357
Additional operating lease commencement date		Jul. 06, 2021
Additional operating lease expiration date		Apr. 30, 2025
Additional operating lease, right-of-use asset								800,000
Additional operating lease, liabilities								$ 800,000
Operating lease, option to extend		The amended lease provides the Company with the option to extend the term of the lease for an additional two years.
Operating lease, existence of option to extend [true false]		true

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Non-Cancellable Leases (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Future minimum lease payments under non-cancellable leases
2023	$ 2,532
2024	2,608
2025	173
Total lease payments	5,313
Less imputed interest	(237)
Present value of lease liabilities	$ 5,076

Commitments and Contingencies_3

Commitments and Contingencies - Summary of Lease Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Operating lease right-of-use assets	$ 4,753	$ 4,939
Current portion of operating lease liabilities	$ 2,359	$ 1,507
Operating Lease Liability Current Statement Of Financial Position Extensible List	Liabilities Current	Liabilities Current
Non-current portion of operating lease liabilities	$ 2,717	$ 3,532
Operating Lease Liability Noncurrent Statement Of Financial Position Extensible List	Other long term liabilities	Other long term liabilities
Total operating lease liabilities	$ 5,076	$ 5,039

Commitments and Contingencies_4

Commitments and Contingencies - Summary of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Operating Leases (Details)	Dec. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Weighted average remaining lease term in years	2 years 1 month 6 days
Weighted average discount rate	4.69%

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option granted to purchase shares		3,459,500	1,311,897
Weighted average grant date fair value per share of stock options granted		$ 10.32	$ 34.07
Aggregate grant date fair value of stock options granted		$ 35,700	$ 44,700
Aggregate intrinsic value of stock options exercised		3,500	9,900
Stock based compensation expense		22,854	16,450
Unrecognized compensation cost		$ 53,300
Expected weighted average period		2 years 9 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vest period		4 years
Member of Board of Directors | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vest period		3 years
Member of Board of Directors | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vest period		1 year
2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	2,200,000
Percentage of increase in reserved common shares	4%
Number of common shares available for future issuance		992,231
2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares available for future issuance		0
2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	315,000
Number of common shares available for future issuance		959,603
Weighted average grant date fair value per share of stock options granted		$ 18.39
Stock based compensation expense		$ 300	$ 300
2019 ESPP | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	3,150,000
Percentage of increase in reserved common shares	1%

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity for Awards (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of shares, Outstanding balance		5,435,304
Number of shares, Granted		3,459,500	1,311,897
Number of shares, Exercised		(270,376)
Number of shares, forfeitures		(254,450)
Number of shares, Expired		(95,331)
Number of shares, Outstanding balance		8,274,647	5,435,304
Number of shares, Exercisable as of December 31, 2021		4,286,461
Weighted average exercise price, Outstanding balance		$ 19.77
Weighted average exercise price, Granted		15.97
Weighted average exercise price, Exercised		1.83
Weighted average exercise price, Forfeitures		29.77
Weighted average exercise price, Expired		34.72
Weighted average exercise price, Outstanding balance		18.28	$ 19.77
Weighted average exercise price, Exercisable as of December 31, 2021		$ 14.70
Weighted average remaining contractual life, Outstanding		7 years 7 months 6 days	8 years
Weighted average remaining contractual life, Exercisable		6 years 4 months 24 days
Aggregate intrinsic value, Outstanding value	[1]	$ 20,598	$ 64,981
Aggregate intrinsic value, Exercisable as of December 31, 2021	[1]	$ 18,454
[1]The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at December 31, 2022 and 2021.

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock based compensation expense	$ 22,854	$ 16,450
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock based compensation expense	8,901	6,215
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock based compensation expense	$ 13,953	$ 10,235

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Fair Values of Options Granted to Employees and Directors (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.82%	0.78%
Risk-free interest rate, maximum	4.15%	1.51%
Expected dividend yield	0%	0%
Expected volatility, minimum	70%	70%
Expected volatility, maximum	71%	73%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	5 years 6 months	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life	6 years 3 months	6 years 3 months

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (101,067)	$ (85,805)
Denominator:
Weighted-average common shares outstanding, basic	38,897,442	36,739,269
Weighted-average common shares outstanding, diluted	38,897,442	36,739,269
Net loss per share, basic	$ (2.60)	$ (2.34)
Net loss per share, diluted	$ (2.60)	$ (2.34)

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Outstanding Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount	8,274,647	5,435,304

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Expected Income Tax Expense (Benefit) using Federal Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Expected income tax benefit at the federal statutory rate	21%	21%
State income taxes, net of federal benefit	7.40%	7.90%
Non-deductible items	(0.90%)	0.40%
Research and development credit, net	3.90%	4.10%
Other	0.10%	0%
Change in valuation allowance	(31.50%)	(33.40%)
Total	0%	0%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 57,746	$ 52,231
Research and development tax credits	12,613	7,726
R&D capitalized expenses	17,148
Accrued compensation and stock compensation	10,274	6,055
Other	142	20
Gross deferred tax assets	97,923	66,032
Less: valuation allowance	$ (97,923)	$ (66,032)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Valuation allowance	$ 97,923,000	$ 66,032,000
Change in valuation allowance	31,800,000	28,800,000
Unrecognized tax benefits	0	0
Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 210,900,000	$ 191,100,000
Operating loss carryforwards, expiration beginning year	2034	2034
Federal | Research and Development Tax Credit
Income Taxes [Line Items]
Tax credit carryforwards	$ 9,200,000	$ 5,400,000
Tax credit carryforwards, expiration beginning year	2030	2030
State
Income Taxes [Line Items]
Operating loss carryforwards	$ 212,800,000	$ 191,400,000
Operating loss carryforwards, expiration beginning year	2035	2035
State | Research and Development Tax Credit
Income Taxes [Line Items]
Tax credit carryforwards	$ 4,300,000	$ 3,000,000
Tax credit carryforwards, expiration beginning year	2030	2030

Employee Benefits - Additional

Employee Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Contributions to 401(k) Plan	$ 0.6	$ 0.5
Maximum
Defined Contribution Plan Disclosure [Line Items]
Maximum matching contribution percentage of employees salary	4%

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Sales Agreement Prospectus shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) shares
Subsequent Event [Line Items]
Issuance of common stock, Shares | shares	4.6
Received deducting commissions related to sales agreement | $	$ 44.7