Climb Bio (CLYM) 10-Q 8 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	ELIEM THERAPEUTICS, INC.
Entity Central Index Key	0001768446
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-40708
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-2273741
Entity Address, Address Line One	23515 NE Novelty Hill Road
Entity Address, Address Line Two	Suite B221 #125
Entity Address, City or Town	Redmond
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98053
City Area Code	425
Local Phone Number	276-2300
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	ELYM
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Entity Common Stock, Shares Outstanding		26,554,316

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash equivalents	$ 62,819	$ 20,487
Short-term marketable securities	83,199	0
Prepaid expenses and other current assets	12,614	1,511
Total current assets	158,632	21,998
Long-term marketable securities	23,619	0
Other long term assets	0	2,633
Total assets	182,251	24,631
Current liabilities:
Accounts payable	2,579	1,086
Accounts payable, related party	0	207
Accrued expenses	2,979	1,219
Accrued expenses, related party	32	0
Redeemable convertible preferred stock tranche liability	0	551
Total current liabilities	5,590	3,063
Total liabilities	5,590	3,063
Commitments and contingencies (Note 5)
Redeemable convertible preferred stock, $0.0001 par value, 10000000 and 12,909,389 shares authorized, 7140157 shares issued and outstanding with aggregate liquidation preference of $0 and $49,891 at September 30, 2021 and December 31, 2020, respectively	0	46,551
Stockholders’ deficit:
Common stock, $0.0001 par value per share, 250000000 and 40,000,000 shares authorized; 26199262 and 3,418,751 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	3	1
Additional paid-in capital	241,747	3,152
Accumulated other comprehensive income	(18)	0
Accumulated deficit	(65,071)	(28,136)
Total stockholders’ deficit	176,661	(24,983)
Total liabilities, redeemable convertible preferred stock, and stockholders’ deficit	$ 182,251	$ 24,631

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Temporary Equity, par value	$ 0.0001	$ 0.0001
Temporary Equity, Shares Authorized	10,000,000	12,909,389
Temporary Equity, Shares Issued	0	7,140,157
Temporary Equity, Shares Outstanding	0	7,140,157
Temporary Equity, Liquidation Preference	$ 0	$ 49,891
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	250,000,000	40,000,000
Common stock, shares issued	26,199,262	3,418,751
Common stock, shares outstanding	26,199,262	3,418,751

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 5,704	$ 1,930	$ 15,455	$ 4,644
Research and development, related party	285	17	988	286
General and administrative	3,394	312	8,526	888
Total operating expenses	9,383	2,259	24,969	5,818
Loss from operations	(9,383)	(2,259)	(24,969)	(5,818)
Other income (expense):
Change in fair value of redeemable convertible preferred stock tranche liability	0	0	(11,718)	0
Foreign currency gain (loss)	(252)	1	(268)	13
Other income, net	20	0	20	0
Total other income (expense)	(232)	1	(11,966)	13
Net loss	(9,615)	(2,258)	(36,935)	(5,805)
Accretion of redeemable convertible preferred stock to redemption value and cumulative preferred stock dividends	(1,322)	(461)	(4,548)	(1,352)
Net loss attributable to common stockholders	$ (10,937)	$ (2,719)	$ (41,483)	$ (7,157)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.70)	$ (1.46)	$ (5.49)	$ (3.85)
Weighted Average Number of Shares Outstanding, Basic and Diluted	15,585,611	1,863,860	7,554,300	1,859,713
Comprehensive loss:
Net loss	$ (9,615)	$ (2,258)	$ (36,935)	$ (5,805)
Other comprehensive loss
Unrealized Gain (Loss) on Investments	(18)	0	(18)	0
Comprehensive loss	$ (9,633)	$ (2,258)	$ (36,953)	$ (5,805)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholder's Deficit (Unaudited) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]
Beginning balance at Dec. 31, 2019		$ 26,174
Beginning balance (in shares) at Dec. 31, 2019		3,999,133
Beginning balance at Dec. 31, 2019	$ (5,562)		$ 1	$ 1,905	$ (7,468)	$ 0
Beginning balance, shares at Dec. 31, 2019			1,852,797
Accretion of Series A and A-1 Preferred Stock	(439)	$ 439		(439)
Release of restricted stock awards			$ 4,170
Stock-based compensation	134			134
Net loss	(1,916)				(1,916)
Ending balance at Mar. 31, 2020	(7,783)		$ 1	1,600	(9,384)	0
Ending balance, shares at Mar. 31, 2020			1,856,967
Ending balance at Mar. 31, 2020		$ 26,613
Ending balance (in shares) at Mar. 31, 2020		3,999,133
Beginning balance at Dec. 31, 2019		$ 26,174
Beginning balance (in shares) at Dec. 31, 2019		3,999,133
Beginning balance at Dec. 31, 2019	(5,562)		$ 1	1,905	(7,468)	0
Beginning balance, shares at Dec. 31, 2019			1,852,797
Accretion of Series A and A-1 Preferred Stock	1,352
Net loss	(5,805)
Ending balance at Sep. 30, 2020	(12,485)		$ 1	787	(13,273)	0
Ending balance, shares at Sep. 30, 2020			1,865,316
Ending balance at Sep. 30, 2020		$ 27,526
Ending balance (in shares) at Sep. 30, 2020		3,999,133
Beginning balance at Mar. 31, 2020		$ 26,613
Beginning balance (in shares) at Mar. 31, 2020		3,999,133
Beginning balance at Mar. 31, 2020	(7,783)		$ 1	1,600	(9,384)	0
Beginning balance, shares at Mar. 31, 2020			1,856,967
Accretion of Series A and A-1 Preferred Stock	(452)	$ 452		(452)
Release of restricted stock awards, shares			4,174
Stock-based compensation	51			51
Net loss	(1,631)				(1,631)
Ending balance at Jun. 30, 2020	(9,815)		$ 1	1,199	(11,015)	0
Ending balance, shares at Jun. 30, 2020			1,861,141
Ending balance at Jun. 30, 2020		$ 27,065
Ending balance (in shares) at Jun. 30, 2020		3,999,133
Accretion of Series A and A-1 Preferred Stock	(461)	$ 461		(461)
Release of restricted stock awards, shares			4,175
Stock-based compensation	49			49
Net loss	(2,258)				(2,258)
Ending balance at Sep. 30, 2020	(12,485)		$ 1	787	(13,273)	0
Ending balance, shares at Sep. 30, 2020			1,865,316
Ending balance at Sep. 30, 2020		$ 27,526
Ending balance (in shares) at Sep. 30, 2020		3,999,133
Beginning balance at Dec. 31, 2020	$ 46,551	$ 46,551
Beginning balance (in shares) at Dec. 31, 2020	7,140,157	7,140,157
Beginning balance at Dec. 31, 2020	$ (24,983)		$ 1	3,152	(28,136)	0
Beginning balance, shares at Dec. 31, 2020			3,418,751
Series A-1 Preferred Stock Issuance (net of issuance costs and tranche liability)		$ 33,978
Series A-1 Preferred Stock Issuance (net of issuance costs and tranche liability), shares		4,358,972
Reclassification of redeemable convertible preferred stock tranche liability upon settlement		$ 12,269
Exercise of stock options and release of restricted stock awards	105			105
Exercise of stock options and release of restricted stock awards, shares			64,047
Stock-based compensation	297			297
Net loss	(18,601)				(18,601)
Ending balance at Mar. 31, 2021	(43,182)		$ 1	3,554	(46,737)	0
Ending balance, shares at Mar. 31, 2021			3,482,798
Ending balance at Mar. 31, 2021		$ 92,798
Ending balance (in shares) at Mar. 31, 2021		11,499,129
Beginning balance at Dec. 31, 2020	$ 46,551	$ 46,551
Beginning balance (in shares) at Dec. 31, 2020	7,140,157	7,140,157
Beginning balance at Dec. 31, 2020	$ (24,983)		$ 1	3,152	(28,136)	0
Beginning balance, shares at Dec. 31, 2020			3,418,751
Reclassification of redeemable convertible preferred stock tranche liability upon settlement	(12,269)
Accretion of Series A and A-1 Preferred Stock	0
Net loss	(36,935)
Ending balance at Sep. 30, 2021	176,661		$ 3	241,747	(65,071)	(18)
Ending balance, shares at Sep. 30, 2021			26,199,262
Ending balance at Sep. 30, 2021	$ 0	$ 0
Ending balance (in shares) at Sep. 30, 2021	0	0
Beginning balance at Mar. 31, 2021		$ 92,798
Beginning balance (in shares) at Mar. 31, 2021		11,499,129
Beginning balance at Mar. 31, 2021	$ (43,182)		$ 1	3,554	(46,737)	0
Beginning balance, shares at Mar. 31, 2021			3,482,798
Series A-1 Preferred Stock Issuance (net of issuance costs and tranche liability)		$ 59,961
Series A-1 Preferred Stock Issuance (net of issuance costs and tranche liability), shares		3,846,150
Exercise of stock options and release of restricted stock awards	6			6
Exercise of stock options and release of restricted stock awards, shares			7,158
Stock-based compensation	1,050			1,050
Net loss	(8,719)				(8,719)
Ending balance at Jun. 30, 2021	(50,845)		$ 1	4,610	(55,456)	0
Ending balance, shares at Jun. 30, 2021			3,489,956
Ending balance at Jun. 30, 2021		$ 152,759
Ending balance (in shares) at Jun. 30, 2021		15,345,279
Proceeds from issuance of common stock in initial public offering	83,144		$ 1	83,143
Proceeds from issuance of common stock in initial public offering, Shares			7,360,000
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	152,759	$ (152,759)	$ 1	152,758
Conversion of redeemable convertible preferred stock to common stock upon initial public offering, Shares		(15,345,279)	15,345,279
Release of restricted stock awards, shares			4,027
Stock-based compensation	1,236			1,236
Other comprehensive loss	(18)					(18)
Net loss	(9,615)				(9,615)
Ending balance at Sep. 30, 2021	176,661		$ 3	$ 241,747	$ (65,071)	$ (18)
Ending balance, shares at Sep. 30, 2021			26,199,262
Ending balance at Sep. 30, 2021	$ 0	$ 0
Ending balance (in shares) at Sep. 30, 2021	0	0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholder's Deficit (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Series A1 Preferred Stock [Member]
Stock issuance cost			$ 22
Series B Preferred Stock [Member]
Stock issuance cost		$ 39
Common Stock [Member]
Stock issuance cost	$ 8,856

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (36,935)	$ (5,805)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,583	234
Change in fair value of redeemable convertible preferred stock tranche liability	11,718	0
Amortization of premiums and accretion of discounts	83	0
Foreign currency gain from remeasurement	(245)	59
Changes in operating assets and liabilities:
Prepaid expenses and other assets	11,103	(2,235)
Long-term assets	2,633	(1,361)
Accounts payable	1,494	82
Accrued liabilities	1,760	611
Accounts payable and accrued liabilities, related party	(176)	(59)
Net cash used in operating activities	(28,188)	(8,474)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of marketable securities	(106,919)	0
Net cash used in investing activities	(106,919)	0
Cash flows from financing activities
Proceeds from issuance of common stock sold in initial public offering, net issuance costs	83,144	0
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	93,939	0
Proceeds from the exercise of stock options	111	0
Net cash provided by financing activities	177,194	0
Effect of exchange rate changes on cash and cash equivalents	245	(59)
Net change in cash and cash equivalents	42,332	(8,533)
Cash and cash equivalents at beginning of period	20,487	21,223
Cash and cash equivalents at end of period	62,819	12,690
Supplemental disclosure of cash flow information:
Conversion of redeemable convertible preferred stock to common stock	152,759	0
Redeemable convertible preferred stock accretion	$ 0	$ 1,352

Description of Organization and

Description of Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Description of Organization and Summary of Significant Accounting Policies	1. Description of Organization and Summary of Significant Accounting Policies Organization Eliem Therapeutics, Inc. (the Company) is a clinical-stage biotechnology company focused on developing novel therapies for neuronal excitability disorders to address unmet needs in chronic pain, neuropsychiatry, epilepsy and other disorders of the peripheral and central nervous systems. Headquartered in Redmond, Washington, the Company was incorporated on October 18, 2018 as a Delaware corporation. Basis of Presentation and Principles of Consolidation The accompanying interim condensed consolidated financial statements of the Company and its wholly owned subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP). All intercompany transactions and balances have been eliminated in consolidation. The accompanying condensed consolidated balance sheet as of September 30, 2021, and condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of cash flows, and condensed consolidated statements of redeemable convertible preferred stock and stockholders’ equity (deficit) for the three and nine months ended September 30, 2021 and 2020, are unaudited. The consolidated balance sheet as of December 31, 2020 was derived from the audited financial statements as of and for the year ended December 31, 2020, but does not include all disclosures required by U.S. GAAP. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2020, and, in the opinion of management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2021, the condensed results of its operations as of the three and nine months ended September 30, 2021 and 2020, and its cash flows for the nine months ended September 30, 2021 and 2020. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2021 and 2020 are also unaudited. The condensed results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the full year ending December 31, 2021 or any other period. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements included in the Company's final prospectus dated August 9, 2021 and filed with the Securities and Exchange Commission, or SEC, on August 11, 2021 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended. Reverse Stock Split In July 2021, the Company's board of directors approved an amendment to the Company's certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 1-for-2 basis, which was effected on July 29, 2021 (the Reverse Stock Split). The number of authorized shares and the par values of the common stock were not adjusted as a result of the Reverse Stock Split. In connection with the Reverse Stock Split, the number of authorized shares, outstanding shares, and the conversion ratio for the Company's redeemable convertible preferred stock was proportionately adjusted such that the common stock issuable upon conversion of such preferred stock was decreased in proportion to the Reverse Stock Split. All references to common stock and options to purchase common stock share data, per share data, and related information contained in the condensed consolidated financial statements have been retroactively adjusted to reflect the effect of the Reverse Stock Split for all periods presented. Initial Public Offering On August 12, 2021, the Company completed its initial public offering (IPO) of 7,360,000 shares of common stock, including the underwriters' full exercise of their over-allotment option at the IPO price of $ 12.50 per share. Gross proceeds from the IPO were $ 92.0 million, and the net proceeds were $ 83.1 million, after deducting underwriting discounts of $ 6.4 million and $ 2.5 million of offering costs payable by the Company. At the closing of the IPO, all of the Company's then outstanding redeemable convertible preferred stock was automatically converted into an aggregate of 15,345,279 shares of common stock. The related carrying value of the redeemable convertible preferred stock of $ 152.8 million was reclassified to common stock and additional paid-in capital. Liquidity Since inception, the Company has experienced recurring losses from operations and generated negative cash flows from operations. The Company has an accumulated deficit of $ 65.1 million as of September 30, 2021 and expects to incur additional losses from operations in the future. The Company estimates the available cash, cash equivalents, and marketable securities as of September 30, 2021 will be sufficient to meet its projected operating requirements for at least the next twelve months from the filing date of these unaudited condensed consolidated financial statements. Therefore, based on management's updated evaluation of the Company's ability to continue as a going concern, management has concluded the factors that previously raised substantial doubt about the Company's ability to continue as a going concern no longer exist as of the issuance date of these unaudited condensed consolidated financial statements. The Company will need to obtain substantial additional funding to develop and commercialize the Company's clinical programs as currently contemplated. The Company expects to finance future cash needs through equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other marketing and distribution arrangements, but there are no assurances that the Company will be able to raise sufficient amounts of funding in the future on acceptable terms, or at all. These condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates continuity of operations, the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. Use of Estimates The preparation of the interim condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and disclosures. Accordingly, actual results could differ from those estimates. Key management estimates include those related to the valuation of assets acquired, accrual of research and development expenses, the valuation of stock-based awards, the valuation of common stock and redeemable convertible preferred stock, and the valuation of redeemable convertible preferred stock tranche liabilities. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company’s cash is held by two financial institutions in the United States (U.S.) and two financial institutions in the United Kingdom (U.K.). The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s deposits held in the U.S. and U.K. may exceed the Federal Depository Insurance Corporation and Financial Services Compensation Scheme, respectively, insured limits. The Company has investments in money market funds, U.S. government debt securities, commercial paper, and corporate bonds with high-quality accredited financial institutions. Risks and 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, protection of proprietary technology, dependence on key personnel, reliance on single-source vendors and collaborators, availability of raw materials, patentability of the Company’s products and processes and clinical efficacy and safety of the Company’s products under development, compliance with government regulations and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical studies, clinical trials, and regulatory approval, prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance and reporting. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained or maintained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate revenue from product sales. The Company operates in an environment of rapid technological change and substantial competition from other pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and other third parties. Moreover, the current COVID-19 pandemic, which is impacting worldwide economic activity, poses risk that the Company or its employees, contractors, suppliers, and other partners may be prevented from conducting business activities for an indefinite period of time which may delay the start-up and conduct of the Company’s clinical trials, and negatively impact manufacturing and testing activities performed by third parties. Any significant delays may impact the use and sufficiency of the Company’s existing cash reserves, and the Company may be required to raise additional capital earlier than it had previously planned. The Company may be unable to raise additional capital if and when needed, which may result in delays or suspension of its development plans. The extent to which the pandemic will impact the Company’s business will depend on future developments that are highly uncertain and cannot be predicted at this time. Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker (the CODM). The Company’s CODM is its chief executive officer who reviews financial information together with certain operating metrics principally to make decisions about how to allocate resources and to measure the Company’s performance. Management has determined that the Company operates as a single operating and reportable segment. The Company’s CODM evaluates financial information on a consolidated basis. As the Company operates as one operating segment, all required segment financial information is found in the interim condensed consolidated financial statements. Fair Value Measurement Assets and liabilities recorded at fair value on a recurring basis in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The Company measures fair value based on a three-tier hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 —Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2 —Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the assets or liabilities. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In determining fair value, the Company utilizes quoted market prices, or valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value. There were no transfers into or out of Level 3 for any of the periods presented. The Company’s fair value measurements as of September 30, 2021 and December 31, 2020 was as follows (in thousands): September 30, 2021 Level 1 Level 2 Level 3 Balance Assets: Cash and cash equivalents: Money market funds $ 38,412 $ — $ — $ 38,412 Marketable securities: U.S. government debt securities 3,995 — — 3,995 Corporate bonds — 102,823 — 102,823 Total assets $ 42,407 $ 102,823 $ — $ 145,230 December 31, 2020 Level 1 Level 2 Level 3 Balance Liabilities: Redeemable convertible preferred stock $ — $ — $ 551 $ 551 Total liabilities $ — $ — $ 551 $ 551 The redeemable convertible preferred stock tranche liability was settled on March 9, 2021. Summary of Significant Accounting Policies Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. As of September 30, 2021, the Company's cash equivalents consisted of money market funds. There were no cash equivalents as of December 31, 2020. Deferred Offering Costs Costs that were directly related to the Company’s IPO were deferred for expense recognition and capitalized and recorded within prepaid and other current assets on the accompanying condensed consolidated balance sheet. These costs consist of legal fees, accounting fees, and other applicable professional services. These deferred offering costs were reclassified to additional paid in capital upon the closing of the IPO. As of September 30, 2021, there were no deferred offering costs capitalized. Investments in Marketable Securities Marketable securities are classified as available-for-sale, primarily consisting of U.S. government debt securities, commercial paper, and corporate bonds, and are reported at fair value. Unrealized holding gains and losses are reflected as a separate component of stockholders' equity (deficit) in accumulated other comprehensive loss until realized. Realized gains and losses on the sale of these securities are recognized in other income, net. The cost of marketable securities sold is based on the specific identification method. The Company periodically reviews its available-for-sale securities to assess for credit impairment. Some of the factors considered in assessing impairment include the extent to which the fair value is less than the amortized cost basis, adverse conditions related to the security, an industry or geographic area, changes to security rating or sector credit ratings, and other relevant market data. There have been no other significant changes in the Company’s accounting policies during the three and nine months ended September 30, 2021. Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), related to leases to increase transparency and comparability among organizations by requiring the recognition of right-of-use (ROU) assets obtained in exchange for lease liabilities on the balance sheet. Most prominent among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases. Under the standard, disclosures are required to meet the objective of enabling users of consolidated financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The effective date of this update for nonpublic companies is for fiscal years beginning after December 15, 2021 and interim periods therein. The Company estimates that adoption will not have a material impact on its consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standard changes how entities will measure credit losses for most financial assets, including accounts and notes receivables. The standard will replace today’s “incurred loss” approach with an “expected loss” model, under which companies will recognize allowances based on expected rather than incurred losses. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The effective date of this update for non-public companies is for fiscal years beginning after December 15, 2022 and interim periods therein. The Company estimates that adoption will not have a material impact on its consolidated financial statements.

Investments

Investments	9 Months Ended
	Sep. 30, 2021
Investments [Abstract]
Investments	2. Investments Investments consists of available-for-sale securities as follows (in thousands): September 30, 2021 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities: U.S. government debt securities $ — $ — $ — $ — Corporate bonds 83,208 — ( 9 ) 83,199 Total short-term marketable securities $ 83,208 $ — $ ( 9 ) $ 83,199 Long-term marketable securities: U.S. government debt securities $ 3,995 $ — $ — $ 3,995 Corporate bonds 19,633 — ( 9 ) 19,624 Total long-term marketable securities $ 23,628 $ — $ ( 9 ) $ 23,619 All the commercial paper, U.S. government debt securities, and corporate bonds designated as short-term marketable securities have a contractual maturity date that is equal to or less than one year from the respective balance sheet date. Those that are designated as long-term marketable securities have a contractual maturity date that is more than one year from the respective balance sheet date. Accrued interest receivable is excluded from the amortized cost and estimated fair value of the Company's marketable securities. Accrued interest receivable of $ 0.3 million is presented separately within the prepaid expenses and other current assets line items in the Company's unaudited condensed consolidated balance sheet as of September 30, 2021. As of September 30, 2021, there were $ 45.9 million of corporate bonds in a continual unrealized loss position for less than 12 months. There were no investments in a continual unrealized loss position for greater than twelve months. As of September 30, 2021, the Company did not intend, nor was the Company more likely than not to be required, to sell its available-for-sale investments before the recovery of the amortized cost basis, which may be maturity. Based on the Company's assessment, it concluded that none of the available-for-sale investments held as of September 30, 2021 were considered to be impaired, as such, no impairment loss was recorded for the three and nine months ended September 30, 2021 .

Certain Balance Sheet Accounts

Certain Balance Sheet Accounts	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Certain Balance Sheet Accounts	3. Certain Balance Sheet Accounts Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Recoverable research and development tax credits $ 6,943 $ — Prepaid research and development expenses 2,661 1,500 Prepaid expenses 1,960 — Other assets 1,050 11 Total prepaid expenses and other current assets $ 12,614 $ 1,511 Accrued Expenses Accrued expenses consist of the following (in thousands): September 30, 2021 December 31, 2020 Accrued payroll $ 1,443 $ 592 Accrued research and development expenses 1,278 627 Other accrued expenses 290 — Total accrued expenses $ 3,011 $ 1,219

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2021
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	. Redeemable Convertible Preferred Stock As of December 31, 2020, the Company’s redeemable convertible preferred stock consisted of the following balance (in thousands, except share and per share amounts): As of December 31, 2020 Issue Shares Shares Issued and Outstanding Carrying Aggregate Series A $ 6.00 2,717,084 2,717,082 $ 17,074 $ 18,569 Series A (Athenen Acquisition) $ 5.80 2,500,000 2,500,000 $ 14,500 $ 15,253 Series A-1 $ 7.80 7,692,305 1,923,075 $ 14,977 $ 16,069 Ending balance 12,909,389 7,140,157 $ 46,551 $ 49,891 In March 2021, Series A-1 preferred stockholders exercised their tranche rights in connection with milestone achievements related to Phase 1 clinical trial results of ETX-155. As a result, the Company issued an additional 4,358,972 shares of Series A-1 redeemable convertible preferred shares for gross proceeds of $ 34.0 million. Upon exercise of the tranche rights, the Company reclassified the $ 12.3 million in preferred stock tranche liability to Series A-1 redeemable convertible preferred stock on the consolidated balance sheet. In May 2021, the Company issued 3,846,150 shares of Series B redeemable convertible preferred stock for gross proceeds of $ 60.0 million. Upon completion of the IPO on August 12, 2021, all of the Company’s then outstanding redeemable convertible preferred stock was converted into an aggregate of 15,345,279 shares of common stock. As of September 30, 2021, the Company had no redeemable convertible preferred stock outstanding. Prior to conversion, the holders of the Series A, Series A-1, and Series B redeemable convertible preferred stock had various rights, preferences, privileges, and restrictions, with respect to voting, dividends, liquidation, and conversion. Liquidation In the event of any liquidation event, either voluntarily or involuntary, the holders of the Series B redeemable convertible preferred stock were entitled to receive, out of the assets of the Company before any payment shall be made or any assets distributed to the holders of Series A and A-1 redeemable convertible preferred stock, the Series B redeemable convertible preferred stock liquidation preference of $ 15.60 , adjusted for any stock splits, combinations, and reorganizations, plus all unpaid cumulative dividends on each such share. If upon the liquidation event, the assets distributed among the holders of the Series B redeemable convertible preferred stock were insufficient to permit the payment to such holders of the full liquidation preference for their shares, then the holders of shares of the Series B redeemable convertible preferred stock shared ratably in any distribution of the assets available for distribution in proportion to their respective amounts, which otherwise would have been payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid the full preferential amount. After the payment to the holders of the Series B redeemable convertible preferred stock of the full preferential amount, the holders of the Series A and Series A-1 redeemable convertible preferred stock were entitled to receive, out of the assets of the Company, the applicable liquidation preference specified for each series of redeemable convertible preferred stock before any payment was made or any assets distributed to the holders of common stock. Liquidation preference was $ 6.00 for Series A and $ 7.80 for Series A-1, each adjusted for any stock splits, combinations, and reorganizations, plus all unpaid cumulative dividends on each such share. If upon the liquidation event, the assets distributed among the holders of the Series A and A-1 redeemable convertible preferred stock were insufficient to permit the payment to such holders of the full liquidation preference for their shares, then the holders of shares of the redeemable convertible preferred stock shared ratably in any distribution of the assets available for distribution in proportion to their respective amounts, which otherwise would have been payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid the full preferential amount. After the payment to the holders of the redeemable convertible preferred stock of the full preferential amount specified above, any remaining assets of the Company would have been distributed pro rata among all holders of the preferred and common stock. A liquidation event required approval by the holders of at least a majority of the outstanding shares of redeemable convertible preferred stock and at least 70 % of the then outstanding shares of Series B redeemable convertible preferred stock. Optional Conversion Each share of redeemable convertible preferred stock was convertible into common stock at the stockholder’s option. The converted shares would have been determined by dividing the original issue price for each series by the applicable conversion price for such series in effect at the date of conversion. The conversion price for each share of redeemable convertible preferred stock was initially equal to the original issuance price applicable to such share, with the exception of the Series A redeemable convertible preferred stock issued related to the Athenen Acquisition, which were convertible at any time after the date of issuance into common stock at the original issue price of the original Series A of $ 6.00 . The conversion ratio was subject to appropriate adjustments for anti-dilution provisions, including stock splits, stock dividends, subdivisions, combinations, recapitalization events or similar events. Specific to the Series B convertible redeemable preferred stock, the conversion ratio was subject to specific anti-dilution provisions adjustments if there was common stock issued for consideration below the Series B issue price. Automatic Conversion Each share of redeemable convertible preferred stock was convertible into common stock at initial conversion rates described under the Optional Conversion heading above, subject to adjustments based on certain antidilution provisions, including stock splits, stock dividends, subdivision, combinations, recapitalization or similar events, as provided by the Company’s certificate of incorporation. Further, all shares of redeemable convertible preferred stock automatically would have converted into common stock upon the vote or written consent of the holders of a majority of the shares of redeemable convertible preferred stock or upon the closing of a firm-commitment underwritten public offering of the Company’s common stock at a stock price of at least $ 17.16 per share and with gross aggregate proceeds to the Company of at least $ 80.0 million. Upon completion of the IPO, the Company's redeemable convertible preferred stock was converted into 15,345,279 shares of common stock. Dividends The holders of shares of Series A, Series A-1, and Series B redeemable convertible preferred stock were entitled to receive cumulative dividends of 8 % per annum of the original issuance price on each share of redeemable convertible preferred stock. The dividends were payable in cash, out of the assets at the time legally available thereof, when, as and if declared by the Board of Directors, on an equal basis according to the number of shares of redeemable convertible preferred stock held by such holders, prior and in preference to the common stock. As of December 31, 2020, the Company had total dividends in arrears for the Series A redeemable convertible preferred stock of $ 3.8 million and $ 2.5 million, or $ 0.72 and $ 0.48 per share, respectively, and for Series A-1 redeemable convertible preferred stock of $ 2.5 million and $ 1.1 million, or $ 0.40 and $ 0.56 per share. As of September 30, 2021, the Company had no dividends in arrears as all shares of redeemable convertible preferred stock converted to common stock upon the completion of the IPO. Redemption Under certain circumstances, subsequent to the occurrence of a deemed liquidation event, defined as (1) a majority of the holders of the then outstanding redeemable convertible preferred stock and (2) at least 70% of the then outstanding shares of the Series B redeemable convertible preferred stock could have required the Company to redeem their shares at a price per share equal to the liquidation amount, to the extent that sufficient funds were available. Additionally, holders of the Company’s Series A and Series A-1 redeemable convertible preferred stock initially had the option to redeem their shares beginning in October 2026. As a result, these shares were considered probable of becoming redeemable since redemption is solely dependent on the passage of time. As such, the Company adjusted the carrying value of the redeemable convertible preferred stock by accreting changes in the redemption value over the period from the date of issuance to the earliest redemption date of October 2026 . In October 2020, the Company amended the terms of their Certificate of Incorporation to remove the redemption option of their Series A and Series A-1 redeemable convertible preferred stock, as a result the Company ceased recording adjustments to the carrying value of its outstanding redeemable convertible preferred stock for accretion to redemption value. There was no change in value as a result of this modification. There was no accretion to redemption value recorded for the nine months ended September 30, 2021. Voting The holders of the Company’s Series B redeemable convertible preferred stock, voting together as a class, were entitled to elect one (1) member of the Board of Directors (the Series B director). The holders of the Company’s Series A and Series A-1 redeemable convertible preferred stock, voting together as a class, were entitled to elect two (2) members of the Board of Directors (the Series A directors). The holders of the shares of common stock and of any other class or series of voting stock (including the preferred stock), voting together as a class, were entitled to elect the balance of the Company’s directors. Stockholder Rights The holders of the Company’s redeemable convertible preferred stock had protective provisions that required preferred stockholders representing a majority of the outstanding redeemable convertible preferred stock, voting as a single class (on an as-converted basis), to consent to specific actions including the following: changes in the corporation’s certificate of incorporation or bylaws that would affect, alter or change the preference or rights of the redeemable convertible preferred stock, changes in the authorized number of shares, declaration or payment of dividends, repurchase of shares, changes in the size of the Board of directors, creation of a new class or series of stock, or taking any action that would cause a liquidation event. Further, the holders of the Company's Series B redeemable convertible preferred stock had additional protective provisions that required Series B preferred stockholders representing 70% of the outstanding shares of the Series B redeemable convertible preferred stock to consent to specific actions including the following: changes in the corporation’s certificate of incorporation or bylaws that would affect, alter or change the preference or rights of the Series B redeemable convertible preferred stock, changes in the authorized number of shares of Series B redeemable convertible preferred stock, declaration or payment of dividends or distributions shares of capital stock other than the Series A, Series A-1, and Series B redeemable convertible preferred stock, sell shares of Common Stock to the public at price below $ 17.16 in a firm-commitment underwritten public offering, or taking any action that would cause a liquidation event that would results in proceeds of less than $ 17.16 per share of the Series B redeemable convertible preferred stock. Additionally, the holders of the Company’s Series A and Series A-1 redeemable convertible preferred stock had additional protective provisions that required preferred stockholders representing a majority of the outstanding redeemable convertible preferred stock, voting as a single class (on an as-converted basis), to consent to specific actions including the following: changes in the corporation’s certificate of incorporation or bylaws that would affect, alter or change the preference or rights of the Series A and Series A-1 redeemable convertible preferred stock and changes or reclassifications of any existing security of the Company that is pari passu with the Series A and/or Series A-1 redeemable convertible preferred stock.

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock Tranche Liability	9 Months Ended
	Sep. 30, 2021
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock Tranche Liability	. Redeemable Convertible Preferred Stock Tranche Liability The purchasers of Series A-1 redeemable convertible preferred stock also received tranche rights, which provided them the right to purchase additional shares of Series A-1 redeemable convertible preferred stock in an additional future tranche. This tranche was for the purchase of Series A-1 and was valued based upon the Company achieving certain future milestones and utilized a valuation model that reflected both potential outcomes of success or failure to meet the milestone. Upon issuance in October 2020, the Series A-1 redeemable convertible preferred tranche liability was valued at $ 0.86 per share. There was no change in value from the date of issuance and December 31, 2020. The Company estimated the fair value of the Series A-1 Tranche Rights using a probability-weighted present value model that considered the probability of triggering the Series A-1 Tranche Rights through achievement of the clinical development milestones specified in the Series A-1 Purchase Agreement. These estimates were based, in part, on subjective assumptions. Changes to these assumptions could have had a significant impact on the reported fair value of the Series A-1 Tranche Rights. The following reflects the significant quantitative inputs used in the valuation of the redeemable convertible preferred stock tranche liability: Series A-1 Estimated fair value of redeemable convertible preferred stock $ 6.94 - $ 11.10 Discount rate 0.10 % Dividend yield 0 % Expected term (years) 0.25 - 0.45 Expected volatility N/A Probability of milestone achievement 80 % - 100 % Strike price $ 7.80 Fair value of each tranche feature $ 0.86 - $ 3.32 The Series A-1 redeemable convertible preferred tranche liability was settled on March 9, 2021 with the achievement of milestones set forth in the Series A-1 stock purchase agreement. The fair value of the liability was remeasured prior to settlement, resulting in the Company recognizing a loss in the consolidated statement of operations and comprehensive loss of $ 11.7 million during the nine months ended September 30, 2021 . Immediately thereafter, the balance of the redeemable convertible preferred stock tranche liability of $ 12.3 million was reclassified to Series A-1 redeemable convertible preferred stock. A rollforward of the redeemable convertible preferred stock tranche liability is as follows (in thousands): Balance at December 31, 2020 $ 551 Change in fair value 11,718 Settlement upon issuance of Series A-1 redeemable convertible preferred stock ( 12,269 ) Balance at September 30, 2021 $ —

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	. Commitments and Contingencies Operating Leases The Company leases office space in the United Kingdom under non-cancelable operating leases. Total rent expense for the three months ended September 30, 2021 and 2020 was $ 0.1 million and $ 13,000 , respectively. Total rent expense for the nine months ended September 30, 2021 and 2020 was $ 0.1 million and $ 38,000 , respectively. As of September 30, 2021, future minimum lease payments under non-cancelable operating leases were $ 0.6 million, the terms of which expire on various dates through June 30, 2023 . Legal Proceedings From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. Indemnification In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless, and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company intends to enter into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance coverage that reduces its exposure and enables the Company to recover a portion of any future amounts paid. The Company believes the estimated fair value of these indemnification agreements in excess of applicable insurance coverage is immaterial.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	. Stock-Based Compensation 2019 Plan In 2019, the Company adopted the 2019 Equity Incentive Plan (the 2019 Plan). The 2019 Plan provides for the Company to grant qualified stock options, non-qualified stock options, and restricted stock awards to employees, non-employee directors and consultants of the Company under terms and provisions established by the board of directors. Under the terms of the 2019 Plan, options are granted at an exercise price no less than fair value of the Company’s common stock on the grant date, except in certain cases related to employees outside of the U.S. However, for any employee who is a 10% or greater stockholder, options are granted at an exercise price no less than 110 % of the fair value of the Company’s common stock on the grant date. Option awards granted typically have 10-year terms measured from the option grant date. However, if any employee is a 10% or greater stockholder, the awards have 5-year terms measured from the option grant date. While no s hares are available for future issuance under the 2019 Plan, it continues to govern outstanding equity awards granted thereunder. 2021 Plan and ESPP The compensation committee of the Company's board of directors adopted and the Company's stockholders approved the 2021 Equity Incentive Plan (2021 Plan) and the 2021 Employee Stock Purchase Plan (the ESPP ), which became effective immediately prior to the effectiveness of the Company's IPO. The 2021 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The Company's employees, officers, directors and consultants are eligible to receive awards under the 2021 Plan. As of September 30, 2021, the total number of shares authorized for issuance under the 2021 Plan was 2,558,790 . The ESPP allows employees, including executive officers, to contribute up to 15 % of their earnings, subject to certain limitations, for the purchase of the Company's common stock at a price per share equal to the lower of (a) 85 % of the fair market value of a share of common stock on the first day of the offering period, or (b) 85 % of the fair market value of a share of common stock on the last day of the offering period. There were 255,879 shares of common stock reserved for future issuance under our ESPP plan and no shares purchased as of September 30, 2021. Stock Options Awards with vesting conditions under both plans typically include vesting 25 % on the first anniversary of the grant date with the remainder vesting monthly over the following three years. Options Weighted Weighted Aggregate Balance as of December 31, 2020 435,342 $ 0.52 9.19 $ 415 Options granted 2,386,990 3.11 Options cancelled and forfeited ( 25,551 ) 1.86 Options exercised ( 59,466 ) 1.86 150 Balance as of September 30, 2021 2,737,315 $ 2.74 9.33 $ 41,727 Vested and expected to vest, September 30, 2021 2,737,315 $ 2.74 9.33 $ 41,727 Options exercisable as of September 30, 2021 206,339 $ 0.31 8.39 $ 3,646 The aggregate intrinsic value disclosed in the above table is based on the difference between the exercise price of the stock option and the estimated fair value of the Company’s common stock as of the respective period-end dates. The weighted-average grant date fair value of stock options granted during the nine months ended September 30, 2021, was $ 6.71 per share. The Black-Scholes option pricing model for employee and nonemployee stock options incorporates the following assumptions:  Fair Value of Common Stock — Prior to the completion of the Company's IPO, the fair value of the Company's common stock was determined by using straight-line interpolation between the value of common stock derived from valuations performed by independent third party specialists, further described in Note 2 to the consolidated financial statements Summary of Significant Accounting Policies – Fair Value of Common Stock in the Company's final prospectus dated August 9, 2021 and filed with the Securities and Exchange Commission, or SEC, on August 11, 2021 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended. After the completion of the Company's IPO, the fair value of each share of common stock is based on the closing price of the Company's common stock on the date of grant as reported on the Nasdaq Global Market.  Volatility — The expected stock price volatilities are estimated based on the historical and implied volatilities of comparable publicly traded companies as the Company does not have sufficient history of trading its common stock.  Risk-free Interest Rate — The risk-free interest rates are based on US Treasury yields in effect at the grant date for notes with comparable terms as the awards.  Expected Term — The expected term represents the period that the Company’s stock options are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term).  Dividend Yield — The expected dividend yield assumption is based on the Company’s current expectations about its anticipated dividend policy. The fair value of the Company’s stock option awards was estimated at the date of grant using a Black-Scholes option pricing model with the following assumptions for the nine months ended September 30, 2021: Expected term (in years) 5.80 - 6.08 Expected volatility 78.25 % - 79.57 % Risk-free interest rate 0.94 % - 1.13 % Expected dividend yield 0.00 % Restricted Stock The Company has restricted stock awards with service and performance conditions. Awards with a service condition vest 25 % on the first anniversary of the grant date and monthly thereafter. Awards with a performance condition will vest upon the Company’s initiation of a registrational clinical trial to study the efficacy of ETX-810. The probability of achieving performance conditions is assessed each reporting period. As of September 30, 2021, this performance condition was assessed and deemed not probable, and the Company has recognized no stock-based compensation expense relating to these performance awards. The Company also granted restricted stock awards to employees and non-employees with service conditions that are subject to repurchase by the Company at the original purchase price in the event that the award recipient’s employment or relationship is terminated prior to the shares vesting. The activity for restricted stock awards is as follows: Number of Shares Weighted-Average Unvested at December 31, 2020 66,681 $ 1.00 Granted 297,724 8.55 Vested ( 15,766 ) 1.42 Unvested at September 30, 2021 (1) 348,639 7.03 (1) Includes 21,750 restricted stock awards granted in 2018 and still outstanding for the period ended September 30, 2021 , subject to only performance conditions. Stock-Based Compensation The following table sets forth stock-based compensation for stock options, restricted stock awards, and performance awards included in the Company’s consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expense $ 297 $ 45 $ 626 $ 220 General and administrative expense 939 4 1,957 14 Total stock-based compensation expense $ 1,236 $ 49 $ 2,583 $ 234 As of September 30, 2021, there was $ 13.3 million of total unrecognized compensation cost related to unvested stock options and unvested restricted stock awards granted, which is expected to be recognized over a weighted average period of 3.19 years.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	8. Net Loss Per Share Attributable to Common Stockholders The following table shows the computation of basic and diluted net loss per share (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ ( 9,615 ) $ ( 2,258 ) $ ( 36,935 ) $ ( 5,805 ) Accretion of redeemable convertible preferred stock to redemption value and cumulative preferred stock dividends ( 1,322 ) ( 461 ) ( 4,548 ) ( 1,352 ) Net loss attributable to common stockholders ( 10,937 ) ( 2,719 ) ( 41,483 ) ( 7,157 ) Weighted-average common shares used in computed net loss per share attributable to common stockholders, basic and diluted 15,585,611 1,863,860 7,554,300 1,859,713 Net loss per share attributable to common stockholders, basic and diluted $ ( 0.70 ) $ ( 1.46 ) $ ( 5.49 ) $ ( 3.85 ) All outstanding shares of redeemable convertible preferred stock were converted on a 1-for-1 basis to shares of common stock on August 12, 2021, the date of the Company's IPO (see Note 1). The cumulative preferred stock dividend was therefore eliminated upon conversion of the redeemable convertible preferred stock. The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Three and Nine Months Ended September 30, 2021 2020 Common stock options 2,737,315 366,501 Unvested restricted stock awards 348,639 117,556 Redeemable convertible preferred stock — 3,999,133 Total potentially dilutive shares 3,085,954 4,483,190

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	. Related Party Transactions Services Provided by Related Parties The Company has a services agreement with Carnot, LLC. Carnot, LLC was subsequently dissolved and the services agreement transitioned to its successor Carnot Pharma, LLC. The Company reimburses Carnot Pharma, LLC for research and development expenses incurred on its behalf. RA Capital Management, L.P. is the manager of the members of Carnot, LLC and Andrew Levin, a member of the Company's board of directors and former CEO, is the President of Carnot Pharma, LLC. Adam Rosenberg, a member of the Company's board of directors, is a Venture Partner at Carnot Pharma, LLC dba RA Ventures. Amounts invoiced and reimbursed for the three months ended September 30, 2021 and 2020 were approximately $ 0.3 million and $ 17,000 , respectively. Amounts invoiced and reimbursed for the nine months ended September 30, 2021 and 2020 were approximately $ 1.0 million and $ 0.3 million, respectively.

Description of Organization a_2

Description of Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Organization	Organization Eliem Therapeutics, Inc. (the Company) is a clinical-stage biotechnology company focused on developing novel therapies for neuronal excitability disorders to address unmet needs in chronic pain, neuropsychiatry, epilepsy and other disorders of the peripheral and central nervous systems. Headquartered in Redmond, Washington, the Company was incorporated on October 18, 2018 as a Delaware corporation.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying interim condensed consolidated financial statements of the Company and its wholly owned subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP). All intercompany transactions and balances have been eliminated in consolidation. The accompanying condensed consolidated balance sheet as of September 30, 2021, and condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of cash flows, and condensed consolidated statements of redeemable convertible preferred stock and stockholders’ equity (deficit) for the three and nine months ended September 30, 2021 and 2020, are unaudited. The consolidated balance sheet as of December 31, 2020 was derived from the audited financial statements as of and for the year ended December 31, 2020, but does not include all disclosures required by U.S. GAAP. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2020, and, in the opinion of management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2021, the condensed results of its operations as of the three and nine months ended September 30, 2021 and 2020, and its cash flows for the nine months ended September 30, 2021 and 2020. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2021 and 2020 are also unaudited. The condensed results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the full year ending December 31, 2021 or any other period. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements included in the Company's final prospectus dated August 9, 2021 and filed with the Securities and Exchange Commission, or SEC, on August 11, 2021 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended.
Reserve Stock Split	Reverse Stock SplitIn July 2021, the Company's board of directors approved an amendment to the Company's certificate of incorporation to effect a reverse split of shares of the Company's common stock on a 1-for-2 basis, which was effected on July 29, 2021 (the Reverse Stock Split). The number of authorized shares and the par values of the common stock were not adjusted as a result of the Reverse Stock Split. In connection with the Reverse Stock Split, the number of authorized shares, outstanding shares, and the conversion ratio for the Company's redeemable convertible preferred stock was proportionately adjusted such that the common stock issuable upon conversion of such preferred stock was decreased in proportion to the Reverse Stock Split. All references to common stock and options to purchase common stock share data, per share data, and related information contained in the condensed consolidated financial statements have been retroactively adjusted to reflect the effect of the Reverse Stock Split for all periods presented.
Initial Public Offering	Initial Public Offering On August 12, 2021, the Company completed its initial public offering (IPO) of 7,360,000 shares of common stock, including the underwriters' full exercise of their over-allotment option at the IPO price of $ 12.50 per share. Gross proceeds from the IPO were $ 92.0 million, and the net proceeds were $ 83.1 million, after deducting underwriting discounts of $ 6.4 million and $ 2.5 million of offering costs payable by the Company. At the closing of the IPO, all of the Company's then outstanding redeemable convertible preferred stock was automatically converted into an aggregate of 15,345,279 shares of common stock. The related carrying value of the redeemable convertible preferred stock of $ 152.8 million was reclassified to common stock and additional paid-in capital.
Liquidity	Liquidity Since inception, the Company has experienced recurring losses from operations and generated negative cash flows from operations. The Company has an accumulated deficit of $ 65.1 million as of September 30, 2021 and expects to incur additional losses from operations in the future. The Company estimates the available cash, cash equivalents, and marketable securities as of September 30, 2021 will be sufficient to meet its projected operating requirements for at least the next twelve months from the filing date of these unaudited condensed consolidated financial statements. Therefore, based on management's updated evaluation of the Company's ability to continue as a going concern, management has concluded the factors that previously raised substantial doubt about the Company's ability to continue as a going concern no longer exist as of the issuance date of these unaudited condensed consolidated financial statements. The Company will need to obtain substantial additional funding to develop and commercialize the Company's clinical programs as currently contemplated. The Company expects to finance future cash needs through equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other marketing and distribution arrangements, but there are no assurances that the Company will be able to raise sufficient amounts of funding in the future on acceptable terms, or at all. These condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates continuity of operations, the realization of assets and the satisfaction of liabilities and commitments in the normal course of business.
Use of Estimates	Use of Estimates The preparation of the interim condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and disclosures. Accordingly, actual results could differ from those estimates. Key management estimates include those related to the valuation of assets acquired, accrual of research and development expenses, the valuation of stock-based awards, the valuation of common stock and redeemable convertible preferred stock, and the valuation of redeemable convertible preferred stock tranche liabilities. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company’s cash is held by two financial institutions in the United States (U.S.) and two financial institutions in the United Kingdom (U.K.). The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s deposits held in the U.S. and U.K. may exceed the Federal Depository Insurance Corporation and Financial Services Compensation Scheme, respectively, insured limits. The Company has investments in money market funds, U.S. government debt securities, commercial paper, and corporate bonds with high-quality accredited financial institutions.
Risks and Uncertainties	Risks and 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, protection of proprietary technology, dependence on key personnel, reliance on single-source vendors and collaborators, availability of raw materials, patentability of the Company’s products and processes and clinical efficacy and safety of the Company’s products under development, compliance with government regulations and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical studies, clinical trials, and regulatory approval, prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance and reporting. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained or maintained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate revenue from product sales. The Company operates in an environment of rapid technological change and substantial competition from other pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and other third parties. Moreover, the current COVID-19 pandemic, which is impacting worldwide economic activity, poses risk that the Company or its employees, contractors, suppliers, and other partners may be prevented from conducting business activities for an indefinite period of time which may delay the start-up and conduct of the Company’s clinical trials, and negatively impact manufacturing and testing activities performed by third parties. Any significant delays may impact the use and sufficiency of the Company’s existing cash reserves, and the Company may be required to raise additional capital earlier than it had previously planned. The Company may be unable to raise additional capital if and when needed, which may result in delays or suspension of its development plans. The extent to which the pandemic will impact the Company’s business will depend on future developments that are highly uncertain and cannot be predicted at this time.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker (the CODM). The Company’s CODM is its chief executive officer who reviews financial information together with certain operating metrics principally to make decisions about how to allocate resources and to measure the Company’s performance. Management has determined that the Company operates as a single operating and reportable segment. The Company’s CODM evaluates financial information on a consolidated basis. As the Company operates as one operating segment, all required segment financial information is found in the interim condensed consolidated financial statements.
Fair Value Measurement	Fair Value Measurement Assets and liabilities recorded at fair value on a recurring basis in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The Company measures fair value based on a three-tier hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 —Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2 —Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the assets or liabilities. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In determining fair value, the Company utilizes quoted market prices, or valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value. There were no transfers into or out of Level 3 for any of the periods presented. The Company’s fair value measurements as of September 30, 2021 and December 31, 2020 was as follows (in thousands): September 30, 2021 Level 1 Level 2 Level 3 Balance Assets: Cash and cash equivalents: Money market funds $ 38,412 $ — $ — $ 38,412 Marketable securities: U.S. government debt securities 3,995 — — 3,995 Corporate bonds — 102,823 — 102,823 Total assets $ 42,407 $ 102,823 $ — $ 145,230 December 31, 2020 Level 1 Level 2 Level 3 Balance Liabilities: Redeemable convertible preferred stock $ — $ — $ 551 $ 551 Total liabilities $ — $ — $ 551 $ 551 The redeemable convertible preferred stock tranche liability was settled on March 9, 2021.
Cash And Cash Equivalent	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. As of September 30, 2021, the Company's cash equivalents consisted of money market funds. There were no cash equivalents as of December 31, 2020.
Deferred Offering Costs	Deferred Offering Costs Costs that were directly related to the Company’s IPO were deferred for expense recognition and capitalized and recorded within prepaid and other current assets on the accompanying condensed consolidated balance sheet. These costs consist of legal fees, accounting fees, and other applicable professional services. These deferred offering costs were reclassified to additional paid in capital upon the closing of the IPO. As of September 30, 2021, there were no deferred offering costs capitalized.
Investment In Marketable Securities	Investments in Marketable Securities Marketable securities are classified as available-for-sale, primarily consisting of U.S. government debt securities, commercial paper, and corporate bonds, and are reported at fair value. Unrealized holding gains and losses are reflected as a separate component of stockholders' equity (deficit) in accumulated other comprehensive loss until realized. Realized gains and losses on the sale of these securities are recognized in other income, net. The cost of marketable securities sold is based on the specific identification method. The Company periodically reviews its available-for-sale securities to assess for credit impairment. Some of the factors considered in assessing impairment include the extent to which the fair value is less than the amortized cost basis, adverse conditions related to the security, an industry or geographic area, changes to security rating or sector credit ratings, and other relevant market data. There have been no other significant changes in the Company’s accounting policies during the three and nine months ended September 30, 2021.
Recent Accounting Procurement	Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), related to leases to increase transparency and comparability among organizations by requiring the recognition of right-of-use (ROU) assets obtained in exchange for lease liabilities on the balance sheet. Most prominent among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases. Under the standard, disclosures are required to meet the objective of enabling users of consolidated financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The effective date of this update for nonpublic companies is for fiscal years beginning after December 15, 2021 and interim periods therein. The Company estimates that adoption will not have a material impact on its consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standard changes how entities will measure credit losses for most financial assets, including accounts and notes receivables. The standard will replace today’s “incurred loss” approach with an “expected loss” model, under which companies will recognize allowances based on expected rather than incurred losses. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The effective date of this update for non-public companies is for fiscal years beginning after December 15, 2022 and interim periods therein. The Company estimates that adoption will not have a material impact on its consolidated financial statements.

Description of Organization a_3

Description of Organization and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Fair Value Measurements	The Company’s fair value measurements as of September 30, 2021 and December 31, 2020 was as follows (in thousands): September 30, 2021 Level 1 Level 2 Level 3 Balance Assets: Cash and cash equivalents: Money market funds $ 38,412 $ — $ — $ 38,412 Marketable securities: U.S. government debt securities 3,995 — — 3,995 Corporate bonds — 102,823 — 102,823 Total assets $ 42,407 $ 102,823 $ — $ 145,230 December 31, 2020 Level 1 Level 2 Level 3 Balance Liabilities: Redeemable convertible preferred stock $ — $ — $ 551 $ 551 Total liabilities $ — $ — $ 551 $ 551

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments [Abstract]
Investments consists of available-for-sale securities	Investments consists of available-for-sale securities as follows (in thousands): September 30, 2021 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Short-term marketable securities: U.S. government debt securities $ — $ — $ — $ — Corporate bonds 83,208 — ( 9 ) 83,199 Total short-term marketable securities $ 83,208 $ — $ ( 9 ) $ 83,199 Long-term marketable securities: U.S. government debt securities $ 3,995 $ — $ — $ 3,995 Corporate bonds 19,633 — ( 9 ) 19,624 Total long-term marketable securities $ 23,628 $ — $ ( 9 ) $ 23,619

Certain Balance Sheet Accounts

Certain Balance Sheet Accounts (Tables)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): September 30, 2021 December 31, 2020 Recoverable research and development tax credits $ 6,943 $ — Prepaid research and development expenses 2,661 1,500 Prepaid expenses 1,960 — Other assets 1,050 11 Total prepaid expenses and other current assets $ 12,614 $ 1,511
Summary of Accrued Expenses	Accrued expenses consist of the following (in thousands): September 30, 2021 December 31, 2020 Accrued payroll $ 1,443 $ 592 Accrued research and development expenses 1,278 627 Other accrued expenses 290 — Total accrued expenses $ 3,011 $ 1,219

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock (Tables)	9 Months Ended
	Sep. 30, 2021
Temporary Equity Disclosure [Abstract]
Schedule of Redeemable Convertible Preferred Stock	As of December 31, 2020, the Company’s redeemable convertible preferred stock consisted of the following balance (in thousands, except share and per share amounts): As of December 31, 2020 Issue Shares Shares Issued and Outstanding Carrying Aggregate Series A $ 6.00 2,717,084 2,717,082 $ 17,074 $ 18,569 Series A (Athenen Acquisition) $ 5.80 2,500,000 2,500,000 $ 14,500 $ 15,253 Series A-1 $ 7.80 7,692,305 1,923,075 $ 14,977 $ 16,069 Ending balance 12,909,389 7,140,157 $ 46,551 $ 49,891

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock Tranche Liability (Tables)	9 Months Ended
	Sep. 30, 2021
Temporary Equity Disclosure [Abstract]
Schedule of Valuation of the Redeemable Convertible Preferred Stock Tranche Liability	The following reflects the significant quantitative inputs used in the valuation of the redeemable convertible preferred stock tranche liability: Series A-1 Estimated fair value of redeemable convertible preferred stock $ 6.94 - $ 11.10 Discount rate 0.10 % Dividend yield 0 % Expected term (years) 0.25 - 0.45 Expected volatility N/A Probability of milestone achievement 80 % - 100 % Strike price $ 7.80 Fair value of each tranche feature $ 0.86 - $ 3.32
Schedule of the Rollforward Redeemable Convertible Preferred Stock Tranche Liability	A rollforward of the redeemable convertible preferred stock tranche liability is as follows (in thousands): Balance at December 31, 2020 $ 551 Change in fair value 11,718 Settlement upon issuance of Series A-1 redeemable convertible preferred stock ( 12,269 ) Balance at September 30, 2021 $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Summary of Stock Option Activities	Options Weighted Weighted Aggregate Balance as of December 31, 2020 435,342 $ 0.52 9.19 $ 415 Options granted 2,386,990 3.11 Options cancelled and forfeited ( 25,551 ) 1.86 Options exercised ( 59,466 ) 1.86 150 Balance as of September 30, 2021 2,737,315 $ 2.74 9.33 $ 41,727 Vested and expected to vest, September 30, 2021 2,737,315 $ 2.74 9.33 $ 41,727 Options exercisable as of September 30, 2021 206,339 $ 0.31 8.39 $ 3,646
Summary of Assumptions Used in Black-Scholes Model	The fair value of the Company’s stock option awards was estimated at the date of grant using a Black-Scholes option pricing model with the following assumptions for the nine months ended September 30, 2021: Expected term (in years) 5.80 - 6.08 Expected volatility 78.25 % - 79.57 % Risk-free interest rate 0.94 % - 1.13 % Expected dividend yield 0.00 %
Summary of Restricted Stock Awards	The activity for restricted stock awards is as follows: Number of Shares Weighted-Average Unvested at December 31, 2020 66,681 $ 1.00 Granted 297,724 8.55 Vested ( 15,766 ) 1.42 Unvested at September 30, 2021 (1) 348,639 7.03 (1) Includes 21,750 restricted stock awards granted in 2018 and still outstanding for the period ended September 30, 2021 , subject to only performance conditions.
Summary of Share-based Compensation Expense	The following table sets forth stock-based compensation for stock options, restricted stock awards, and performance awards included in the Company’s consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expense $ 297 $ 45 $ 626 $ 220 General and administrative expense 939 4 1,957 14 Total stock-based compensation expense $ 1,236 $ 49 $ 2,583 $ 234

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share	The following table shows the computation of basic and diluted net loss per share (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ ( 9,615 ) $ ( 2,258 ) $ ( 36,935 ) $ ( 5,805 ) Accretion of redeemable convertible preferred stock to redemption value and cumulative preferred stock dividends ( 1,322 ) ( 461 ) ( 4,548 ) ( 1,352 ) Net loss attributable to common stockholders ( 10,937 ) ( 2,719 ) ( 41,483 ) ( 7,157 ) Weighted-average common shares used in computed net loss per share attributable to common stockholders, basic and diluted 15,585,611 1,863,860 7,554,300 1,859,713 Net loss per share attributable to common stockholders, basic and diluted $ ( 0.70 ) $ ( 1.46 ) $ ( 5.49 ) $ ( 3.85 )
Schedule of Antidilutive Securities Excluded from Computation of Net Loss Per Share Attributable to Common Stockholders	The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Three and Nine Months Ended September 30, 2021 2020 Common stock options 2,737,315 366,501 Unvested restricted stock awards 348,639 117,556 Redeemable convertible preferred stock — 3,999,133 Total potentially dilutive shares 3,085,954 4,483,190

Description of Organization a_4

Description of Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 12, 2021	Sep. 30, 2021	Dec. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Convertible preferred stock, shares issued upon conversion		152,800,000
Stockholders' Equity, Reverse Stock Split		1-for-2
Accumulated deficit		$ (65,071)	$ (28,136)
Cash equivalents			$ 0
Deferred offering costs		$ 0
Entity incorporation date		Oct. 18, 2018
Fair Value Inputs Level 1, 2 and 3 [Member]
Subsidiary Sale Of Stock [Line Items]
Fair value transfer amount		$ 0
IPO [Member]
Subsidiary Sale Of Stock [Line Items]
Proceeds from issuance of common stock in initial public offering, Shares	7,360,000
Shares issued price per share	$ 12.50
Proceeds from issuance initial public offering	$ 92,000
Proceeds from issuance initial public offering net	$ 83,100
Convertible preferred stock, shares issued upon conversion	15,345,279
Deferred offering costs	$ 2,500
Underwriting Discount	$ 6,400

Description of Organization a_5

Description of Organization and Summary of Significant Accounting Policies - Schedule of Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Assets, Fair Value Disclosure	$ 145,230
Liabilities:
Liabilities fair value		$ 551
Money Market Funds [Member]
Assets:
Assets, Fair Value Disclosure	38,412
US Government Debt Securities [Member]
Assets:
Assets, Fair Value Disclosure
Corporate Bonds [Member]
Assets:
Assets, Fair Value Disclosure	102,823
Redeemable Convertible Preferred Stock Tranche Liability [Member]
Liabilities:
Liabilities fair value		551
Level 1 [Member]
Assets:
Assets, Fair Value Disclosure	42,407
Liabilities:
Liabilities fair value
Level 1 [Member] | Money Market Funds [Member]
Assets:
Assets, Fair Value Disclosure	38,412
Level 1 [Member] | US Government Debt Securities [Member]
Assets:
Assets, Fair Value Disclosure	3,995
Level 1 [Member] | Corporate Bonds [Member]
Assets:
Assets, Fair Value Disclosure
Level 1 [Member] | Redeemable Convertible Preferred Stock Tranche Liability [Member]
Liabilities:
Liabilities fair value
Level 2 [Member]
Assets:
Assets, Fair Value Disclosure	102,823
Liabilities:
Liabilities fair value
Level 2 [Member] | Money Market Funds [Member]
Assets:
Assets, Fair Value Disclosure
Level 2 [Member] | US Government Debt Securities [Member]
Assets:
Assets, Fair Value Disclosure
Level 2 [Member] | Corporate Bonds [Member]
Assets:
Assets, Fair Value Disclosure	102,823
Level 2 [Member] | Redeemable Convertible Preferred Stock Tranche Liability [Member]
Liabilities:
Liabilities fair value
Level 3 [Member]
Assets:
Assets, Fair Value Disclosure
Liabilities:
Liabilities fair value		551
Level 3 [Member] | Money Market Funds [Member]
Assets:
Assets, Fair Value Disclosure
Level 3 [Member] | US Government Debt Securities [Member]
Assets:
Assets, Fair Value Disclosure
Level 3 [Member] | Corporate Bonds [Member]
Assets:
Assets, Fair Value Disclosure
Level 3 [Member] | Redeemable Convertible Preferred Stock Tranche Liability [Member]
Liabilities:
Liabilities fair value		$ 551

Investments - Investments consi

Investments - Investments consists of available-for-sale securities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Short Term Marketable Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 83,208
Unrealized Loss	9
Estimated Fair Value	83,199
Long Term Marketable Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	23,628
Unrealized Loss	9
Estimated Fair Value	23,619
US Government Debt Securities [Member] | Long Term Marketable Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,995
Estimated Fair Value	3,995
Corporate Bonds [Member] | Short Term Marketable Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	83,208
Unrealized Loss	9
Estimated Fair Value	83,199
Corporate Bonds [Member] | Long Term Marketable Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	19,633
Unrealized Loss	9
Estimated Fair Value	$ 19,624

Investments (Additional Informa

Investments (Additional Information) (Details) $ in Thousands	Sep. 30, 2021USD ($)
Summary of Investment Holdings [Line Items]
Continuous unrealized loss position, 12 months or longer	$ 0
Corporate Bonds [Member]
Summary of Investment Holdings [Line Items]
Continuous unrealized loss position, less than 12 months	45,900
Prepaid Expenses and Other Current Assets [Member]
Summary of Investment Holdings [Line Items]
Accrued interest receivable	$ 300

Certain Balance Sheet Account_2

Certain Balance Sheet Accounts - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Recoverable research and development tax credits	$ 6,943	$ 0
Prepaid research and development expenses	2,661	1,500
Prepaid expenses	1,960	0
Other assets	1,050	11
Total prepaid expenses and other current assets	$ 12,614	$ 1,511

Certain Balance Sheet Account_3

Certain Balance Sheet Accounts - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued payroll	$ 1,443	$ 592
Accrued research and development expenses	1,278	627
Other accrued expenses	290	0
Total accrued expenses	$ 3,011	$ 1,219

Redeemable Convertible Prefer_5

Redeemable Convertible Preferred Stock - Schedule of Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Temporary Equity [Line Items]
Temporary Equity, Shares Authorized	10,000,000	12,909,389
Temporary Equity, Shares Issued	0	7,140,157
Temporary Equity, Shares Outstanding	0	7,140,157
Temporary Equity, Carrying Value	$ 0	$ 46,551
Temporary Equity, Liquidation Preference	$ 0	$ 49,891
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity, Issue Price		$ 6
Temporary Equity, Shares Authorized		2,717,084
Temporary Equity, Shares Issued		2,717,082
Temporary Equity, Shares Outstanding		2,717,082
Temporary Equity, Carrying Value		$ 17,074
Temporary Equity, Liquidation Preference		$ 18,569
Series A Athenen Acquisition Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity, Issue Price		$ 5.80
Temporary Equity, Shares Authorized		2,500,000
Temporary Equity, Shares Issued		2,500,000
Temporary Equity, Shares Outstanding		2,500,000
Temporary Equity, Carrying Value		$ 14,500
Temporary Equity, Liquidation Preference		$ 15,253
Series A1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity, Issue Price		$ 7.80
Temporary Equity, Shares Authorized		7,692,305
Temporary Equity, Shares Issued		1,923,075
Temporary Equity, Shares Outstanding		1,923,075
Temporary Equity, Carrying Value		$ 14,977
Temporary Equity, Liquidation Preference		$ 16,069

Redeemable Convertible Prefer_6

Redeemable Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Aug. 12, 2021	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Proceeds from issuance of redeemable convertible preferred stock and related tranche rights, net of issuance costs		$ 93,939	$ 0
Temporary Equity, Shares Outstanding		0		7,140,157
Percentage of cumulative dividends receive		8.00%
Redeemable convertible preferred stock tranche liability		$ 0		$ 551
Common stock		26,199,262		3,418,751
Redemption date		Oct. 31, 2026
Accretion of redeemable convertible preferred stock to redemption value		$ 0
Underwritten Public Offering [Member]
Temporary Equity [Line Items]
Temporary equity, automatic conversion, sale of common stock, price per share		$ 17.16
Series A1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock issued during period shares new issues	4,358,972
Proceeds from issuance of redeemable convertible preferred stock and related tranche rights, net of issuance costs	$ 34,000
Temporary Equity, Shares Outstanding				1,923,075
Redeemable convertible preferred stock tranche liability		$ 12,300
Temporary equity liquidation preference		$ 7.80
Dividends preferred stock		$ 2,500		$ 1,100
Preferred dividend, per share		$ 0.40		$ 0.56
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock issued during period shares new issues	3,846,150
Proceeds from issuance of redeemable convertible preferred stock and related tranche rights, net of issuance costs	$ 60,000
Temporary equity liquidation preference		15.60
Temporary equity, automatic conversion, sale of common stock, price per share		$ 17.16
Series B Redeemable Convertible Preferred Stock [Member] | Minimum [Member]
Temporary Equity [Line Items]
Percentage of outstanding shares		70.00%
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity, Shares Outstanding				2,717,082
Temporary equity liquidation preference		$ 6
Sale of stock, price (in dollars per share)		$ 6
Dividends preferred stock		$ 3,800		$ 2,500
Preferred dividend, per share		$ 0.72		$ 0.48
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary Equity, Shares Outstanding	11,499,129	0	3,999,133	7,140,157	15,345,279	15,345,279	3,999,133	3,999,133	3,999,133
Temporary equity, automatic conversion, sale of common stock, price per share		$ 17.16
Temporary equity, automatic conversion, sale of common stock, gross proceeds		$ 80,000
Common stock		15,345,279

Redeemable Convertible Prefer_7

Redeemable Convertible Preferred Stock Tranche Liability - Additional Information - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Oct. 31, 2020
Temporary Equity [Line Items]
Temporary equity, par value	$ 0.0001		$ 0.0001		$ 0.0001
Change in fair value of redeemable convertible preferred stock tranche liability	$ 0	$ 0	$ 11,718	$ 0
Series A 1 Redeemable Convertible Preferred Tranche Liability
Temporary Equity [Line Items]
Temporary equity, par value						$ 0.86
Change in fair value of redeemable convertible preferred stock tranche liability			11,700
Series A - 1 Preferred Stock
Temporary Equity [Line Items]
Change in fair value of redeemable convertible preferred stock tranche liability			$ 12,300

Redeemable Convertible Prefer_8

Redeemable Convertible Preferred Stock Tranche Liability - Schedule of Valuation of The Redeemable Convertible Preferred Stock Tranche Liability (Details) - Series A 1 Tranche Call Option [Member]	9 Months Ended
	Sep. 30, 2021$ / shares
Temporary Equity [Line Items]
Discount rate	0.10%
Dividend yield	0.00%
Strike price	$ 7.80
Minimum [Member]
Temporary Equity [Line Items]
Estimated fair value of redeemable convertible preferred stock	$ 6.94
Expected term (years)	3 months
Probability of milestone achievement	80.00%
Fair value of each tranche feature	$ 0.86
Maximum [Member]
Temporary Equity [Line Items]
Estimated fair value of redeemable convertible preferred stock	$ 11.10
Expected term (years)	5 months 12 days
Probability of milestone achievement	100.00%
Fair value of each tranche feature	$ 3.32

Redeemable Convertible Prefer_9

Redeemable Convertible Preferred Stock Tranche Liability - Schedule of The Rollforward Redeemable Convertible Preferred Stock Tranche Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Temporary Equity Disclosure [Abstract]
Beginning Balance			$ 551
Change in fair value of redeemable convertible preferred stock tranche liability	$ 0	$ 0	11,718	$ 0
Reclassification of redeemable convertible preferred stock tranche liability upon settlement			(12,269)
Ending Balance	$ 0		$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 100,000	$ 13,000	$ 100,000	$ 38,000
Lease payments under non-cancelable operating leases	$ 600,000		$ 600,000
Lease expiration date			Jun. 30, 2023

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Executive Officer Earning Contribution	15.00%
Percentage of fair market value, common stock	85.00%
Number of shares, Granted		21,750
Unrecognized compensation cost	$ 13,300
Unrecognized compensation, weighted average amortization period	3 years 2 months 8 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, award vesting rights, percentage	25.00%
Number of shares, Granted	297,724
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, award vesting rights, percentage	25.00%
Options grants in period, weighted average grant date fair value	$ 6.71
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, description	Under the terms of the 2019 Plan, options are granted at an exercise price no less than fair value of the Company’s common stock on the grant date, except in certain cases related to employees outside of the U.S. However, for any employee who is a 10% or greater stockholder, options are granted at an exercise price no less than 110% of the fair value of the Company’s common stock on the grant date. Option awards granted typically have 10-year terms measured from the option grant date. However, if any employee is a 10% or greater stockholder, the awards have 5-year terms measured from the option grant date. While no shares are available for future issuance under the 2019 Plan, it continues to govern outstanding equity awards granted thereunder.
Share based payment award, purchase price of common stock, percent	110.00%
Share-based payment award, expiration period	5 years
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, description	The compensation committee of the Company's board of directors adopted and the Company's stockholders approved the 2021 Equity Incentive Plan (2021 Plan) and the 2021 Employee Stock Purchase Plan (the ESPP ), which became effective immediately prior to the effectiveness of the Company's IPO. The 2021 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The Company's employees, officers, directors and consultants are eligible to receive awards under the 2021 Plan. As of September 30, 2021, the total number of shares authorized for issuance under the 2021 Plan was 2,558,790.
Share-based payment award, number of shares authorized	2,558,790
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, description	The ESPP allows employees, including executive officers, to contribute up to 15% of their earnings, subject to certain limitations, for the purchase of the Company's common stock at a price per share equal to the lower of (a) 85% of the fair market value of a share of common stock on the first day of the offering period, or (b) 85% of the fair market value of a share of common stock on the last day of the offering period. There were 255,879 shares of common stock reserved for future issuance under our ESPP plan and no shares purchased as of September 30, 2021.
Common stock reserved for future issuance	255,879

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Number of options outstanding, beginning of period	435,342
Number of options granted	2,386,990
Number of options, cancelled and forfeited	(25,551)
Number of options exercised	(59,466)
Number of options outstanding, ending of period	2,737,315	435,342
Number of options, vested and expected to vest	2,737,315
Number of options exercisable, end of period	206,339
Weighted average exercise price outstanding, beginning of period	$ 0.52
Weighted average exercise price, options granted	3.11
Weighted average exercise price, options cancelled and forfeited	1.86
Weighted average exercise price, options exercised	1.86
Weighted average exercise price outstanding, end of period	2.74	$ 0.52
Weighted average exercise price, options vested and expected to vest	2.74
Weighted average exercise price, options exercisable	$ 0.31
Weighted average remaining contracted terms (in years) outstanding, beginning of period		9 years 2 months 8 days
Weighted average remaining contracted terms (in years) outstanding, end of period	9 years 3 months 29 days
Weighted average remaining contracted terms (in years), vested and expected to vest	9 years 3 months 29 days
Weighted average remaining contracted terms (in years), exercisable at end of period	8 years 4 months 20 days
Aggregate intrinsic value outstanding, beginning of period	$ 415
Aggregate intrinsic value options exercised	150
Aggregate intrinsic value outstanding, end of period	41,727	$ 415
Aggregate intrinsic value options vested and expected to vest	41,727
Aggregate intrinsic value options exercisable	$ 3,646

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Assumptions Used in Black-Scholes Model (Details)	9 Months Ended
	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, Minimum	0.94%
Risk-free interest rate, Maximum	1.13%
Dividend yield	0.00%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 9 months 18 days
Expected volatility, Minimum	78.25%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 29 days
Expected volatility, Maximum	79.57%

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Restricted Stock Awards (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Granted		21,750
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Unvested	66,681
Number of shares, Granted	297,724
Number of shares, Vested	(15,766)
Number of shares, Unvested	348,639
Unvested, weighted average grant date fair value per share, beginning balance	$ 1
Granted, weighted average grant date fair value	8.55
Vested, weighted average grant date fair value per share	1.42
Unvested, weighted average grant date fair value per share, ending balance	$ 7.03

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,236	$ 49	$ 2,583	$ 234
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	297	45	626	220
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 939	$ 4	$ 1,957	$ 14

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (9,615)	$ (2,258)	$ (36,935)	$ (5,805)
Accretion of redeemable convertible preferred stock to redemption value and cumulative preferred stock dividends	(1,322)	(461)	(4,548)	(1,352)
Net loss attributable to common stockholders	$ (10,937)	$ (2,719)	$ (41,483)	$ (7,157)
Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, basic and diluted	15,585,611	1,863,860	7,554,300	1,859,713
Net loss per share attributable to common stockholders, basic and diluted	$ (0.70)	$ (1.46)	$ (5.49)	$ (3.85)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Additional Information (Details)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Unit conversion ratio	1-for-1

Net Loss Per Share Attributab_5

Net Loss Per Share Attributable to Common Stockholders - Schedule of Antidilutive Securities Excluded from Computation of Net Loss Per Share Attributable to Common Stockholders (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Redeemable convertible preferred stock	3,085,954	4,483,190	3,085,954	4,483,190
Common Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Redeemable convertible preferred stock	2,737,315	366,501	2,737,315	366,501
Unvested Restricted Stock Awards [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Redeemable convertible preferred stock	348,639	117,556	348,639	117,556
Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Redeemable convertible preferred stock	0	3,999,133	0	3,999,133

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transaction, Amounts of Transaction	$ 300,000	$ 17,000	$ 1,000,000	$ 300,000