Athira Pharma (ATHA) 10-K 22 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 19, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Entity Registrant Name	Athira Pharma, Inc.
Entity Central Index Key	0001620463
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-3368487
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	ATHA
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity File Number	001-39503
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Address Address Line1	18706 North Creek Parkway,
Entity Address Address Line2	Suite 104
Entity Address City Or Town	Bothell,
Entity Address State Or Province	WA
Entity Address Postal Zip Code	98011
City Area Code	425
Local Phone Number	620-8501
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Common Stock, Shares Outstanding		38,326,652
Entity Public Float			$ 96.3
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the definitive proxy statement to be delivered to stockholders in connection with the 2024 annual meeting of stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the Registrant’s fiscal year ended December 31, 2023.
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Seattle, Washington

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 90,584	$ 95,966
Short-term investments	56,835	104,378
Unbilled grant receivable		1,227
Prepaid expenses and other current assets	5,682	5,962
Insurance recovery receivable related to legal settlement (Note 7)	1,628
Total current assets	154,729	207,533
Restricted cash	631	420
Property and equipment, net	3,388	4,053
Operating lease right-of-use asset	1,049	1,263
Long-term investments		44,829
Other long-term assets	448	55
Total assets	160,245	258,153
Current liabilities:
Accounts payable	129	2,501
Accrued liabilities	18,343	8,604
Accrued legal settlement (Note 7)	10,000	10,000
Current operating lease liability	368	326
Total current liabilities	28,840	21,431
Operating lease liability, less current portion	1,217	1,585
Total liabilities	30,057	23,016
Stockholders' equity:
Common stock, $0.0001 par value; 900,000,000 shares authorized at December 31, 2023 and December 31, 2022, respectively; 38,172,603 and 37,877,387 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	4	4
Additional paid-in capital	439,739	428,623
Accumulated other comprehensive loss	(349)	(1,956)
Accumulated deficit	(309,206)	(191,534)
Total stockholders' equity	130,188	235,137
Total liabilities and stockholders' equity	$ 160,245	$ 258,153

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	38,172,603	37,877,387
Common stock, shares outstanding	38,172,603	37,877,387

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development	$ 93,790	$ 61,464
General and administrative	33,304	32,552
Legal settlement		10,000
Insurance recovery related to legal settlement	(1,628)
Total operating expenses	125,466	104,016
Loss from operations	(125,466)	(104,016)
Grant income	157	5,161
Other income, net	7,637	3,216
Net loss	(117,672)	(95,639)
Unrealized gain (loss) on available-for-sale securities	1,607	(1,568)
Comprehensive loss attributable to common stockholders	$ (116,065)	$ (97,207)
Net loss per share attributable to common stockholders, basic	$ (3.09)	$ (2.53)
Net loss per share attributable to common stockholders, diluted	$ (3.09)	$ (2.53)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic	38,020,182	37,733,240
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted	38,020,182	37,733,240

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2021	$ 321,084	$ 4	$ 417,363	$ (388)	$ (95,895)
Beginning balance, shares at Dec. 31, 2021		37,379,077
Issuance of common stock upon exercise of common stock options	309		309
Issuance of common stock upon exercise of common stock options, shares		419,949
Issuance of common stock under employee stock purchase plan	345		345
Issuance of common stock under employee stock purchase plan, shares		78,361
Stock-based compensation	10,606		10,606
Unrealized gain (loss) on available-for-sale securities	(1,568)			(1,568)
Net loss	(95,639)				(95,639)
Ending balance at Dec. 31, 2022	$ 235,137	$ 4	428,623	(1,956)	(191,534)
Ending balance, shares at Dec. 31, 2022		37,877,387
Issuance of common stock upon exercise of common stock options, shares	128,534
Issuance of common stock upon exercise of common stock options and vesting of restricted stock units	$ 167		167
Issuance of common stock upon exercise of common stock options and vesting of restricted stock units, shares		128,534
Issuance of common stock under employee stock purchase plan	326		326
Issuance of common stock under employee stock purchase plan, shares		166,682
Stock-based compensation	10,623		10,623
Unrealized gain (loss) on available-for-sale securities	1,607			1,607
Net loss	(117,672)				(117,672)
Ending balance at Dec. 31, 2023	$ 130,188	$ 4	$ 439,739	$ (349)	$ (309,206)
Ending balance, shares at Dec. 31, 2023		38,172,603

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net loss	$ (117,672,000)	$ (95,639,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	10,623,000	10,606,000
Depreciation expense	969,000	845,000
Non-cash lease expense	214,000	203,000
Amortization of premiums and accretion of discounts on available-for-sale securities, net	(1,414,000)	(422,000)
Changes in operating assets and liabilities:
Unbilled grant receivable	1,227,000	1,109,000
Prepaid expenses and other current and long-term assets, net	(113,000)	(1,257,000)
Insurance recovery receivable related to legal settlement	(1,628,000)
Accounts payable and accrued liabilities	7,367,000	2,101,000
Accrued legal settlement		10,000,000
Operating lease liability	(326,000)	(15,000)
Net cash used in operating activities	(100,753,000)	(72,469,000)
Investing activities
Purchases of available-for-sale securities	(27,671,000)	(95,288,000)
Maturities of available-for-sale securities	123,064,000	154,093,000
Purchases of property and equipment	(304,000)	(1,141,000)
Net cash provided by investing activities	95,089,000	57,664,000
Financing activities
Proceeds from exercise of common stock options and issuance of common stock under employee stock purchase plan.	493,000	654,000
Net cash provided by financing activities	493,000	654,000
Net decrease in cash, cash equivalents and restricted cash	(5,171,000)	(14,151,000)
Cash, cash equivalents and restricted cash, beginning of period	96,386,000	110,537,000
Cash, cash equivalents and restricted cash, end of period	$ 91,215,000	$ 96,386,000

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (117,672)	$ (95,639)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business Organization Athira Pharma, Inc. (the “Company”) was incorporated as M3 Biotechnology, Inc. in the state of Washington on March 31, 2011 and reincorporated in the state of Delaware on October 27, 2015 . In April 2019, the Company changed its name to Athira Pharma, Inc. The Company currently has office and laboratory space in Bothell, Washington. The Company is a late clinical-stage biopharmaceutical company focused on developing small molecules to restore neuronal health and slow neurodegeneration. Liquidity and Capital Resources Since the Company’s inception, it has funded its operations primarily with proceeds from the sale and issuance of common stock, convertible preferred stock, common stock warrants, and convertible notes, and to a lesser extent from grant income and stock option exercises. From the Company’s inception through December 31, 2023, it has raised aggregate net cash proceeds of $ 407.4 million primarily from the issuance of its common stock (excluding option exercises), convertible preferred stock, common stock warrants, and convertible notes. As of December 31, 2023, the Company had $ 147.4 million in cash, cash equivalents, and investments and had not generated positive cash flows from operations. Since the Company’s inception, it has devoted substantially all of its resources to its research and development efforts such as small molecule compound discovery, nonclinical studies and clinical trials, as well as manufacturing activities, establishing and maintaining the Company’s intellectual property portfolio, hiring personnel, raising capital, and providing general and administrative support for these operations. Based upon the Company’s current operating plan, it estimates that its $ 147.4 million of cash, cash equivalents, and investments at December 31, 2023 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next 12 months following the date of the Company’s Annual Report on Form 10-K. At The Market Common Stock Offering In January 2023, the Company entered into a sales agreement with Cantor Fitzgerald and BTIG to sell shares of our common stock having aggregate sales proceeds of up to $ 75.0 million, from time to time, through an “at the market” (“ATM”) equity offering program under which Cantor and BTIG are acting as sales agents. The Company has not sold any securities pursuant to this ATM offering.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Significant Accounting Policies	2 . Significant Accounting Policies Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). The consolidated financial statements include the operations of Athira Pharma, Inc., and its wholly owned Australian subsidiary. All intercompany balances and transactions have been eliminated upon consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related 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. Cash and Cash Equivalents The Company considers highly liquid investments with original maturities of three months or less to be cash equivalents. Restricted Cash Restricted cash consists primarily of collateral pledged in connection with the Company's corporate credit cards. The table below reconciles the balances of cash and cash equivalents and restricted cash reported on the consolidated balance sheets to the balances of cash, cash equivalents and restricted cash reported on the consolidated statements of cash flows. December 31, 2023 2022 Cash and cash equivalents $ 90,584 $ 95,966 Restricted cash 631 420 Cash, cash equivalents and restricted cash $ 91,215 $ 96,386 Short-term and Long-term Investments The Company generally invests its excess cash in investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term investments, and long-term investments on the consolidated balance sheets, classified as available-for-sale, and reported at fair value with unrealized gains and losses included in accumulated other comprehensive loss. Amortization and accretion are included in other income, net. Realized gains and losses on the sale of these securities are recognized in other income, net. The Company periodically evaluates whether declines in fair values of its investments below their book value are due to expected credit losses, as well as the Company's ability and intent to hold the investment until a forecasted recovery occurs. Expected credit losses are recorded as an allowance through other income, net. Concentration of Credit Risk The Company is exposed to credit risk from its deposits of cash in excess of amounts insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses on its deposits of cash since inception. Property and Equipment Property and equipment consist of computer equipment, computer software, laboratory equipment, leasehold improvements and furniture and office equipment. Property and equipment, excluding leasehold improvements, are recorded at cost and depreciation is recognized using the straight-line method based on estimated useful life, generally three to five years . Leasehold improvements are amortized over the shorter of their useful life or the remaining lease term. Maintenance and repairs are charged to expense as incurred, and costs of improvements are capitalized. The Company reviews long-lived assets for impairment whenever events or circumstances indicate the carrying amount of an asset group may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset's carrying amount over its fair value. Gains and losses from asset disposals and impairment losses are classified within the consolidated statements of operations and comprehensive loss in accordance with the use of the asset. There were no impairment losses in the years ended December 31, 2023 and 2022 as there have been no events warranting an impairment analysis. Fair Value Measurements The carrying amounts of certain financial instruments, including cash, cash equivalents, restricted cash, investments, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts. Grant Income In December 2020, the Company accepted a grant from the National Institute on Aging (“NIA”) of the National Institutes of Health (“NIH”) to support its ACT-AD Phase 2 clinical trial for fosgonimeton (then-named ATH-1017), the Company’s lead therapeutic candidate being developed for the treatment of individuals with mild-to-moderate Alzheimer’s disease. The Company recognizes income related to the NIH grant in the accompanying consolidated statements of operations and comprehensive loss as qualifying expenses under the grant agreement are incurred. As of December 31, 2023, the Company has recognized aggregate grant income of $ 15.2 million in connection with the NIH grant, equal to the total grant amount approved. The Company will no t recognize any additional grant income in connection with the NIH grant in the future. During the years ended December 31, 2023 and 2022, the Company recognized grant income of $ 0.2 million and $ 5.2 million, respectively, in connection with the NIH grant. As of December 31, 2022, the Company incurred qualifying expenses in excess of cash received of $ 1.2 million, which is included in unbilled grant receivable on the consolidated balance sheets. The Company received cash of $ 1.4 million related to the NIH grant during the year ended December 31, 2023, compared to $ 6.3 million during the year ended December 31, 2022. Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of the pipeline from the Company’s proprietary drug discovery platform (“ATH platform”), the Company’s drug discovery efforts and the development of its drug candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expensed when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company adjusts the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception. General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs, consisting of employee salaries, related benefits, and stock-based compensation expense for employees in the executive, legal, finance and accounting, human resources, and other administrative functions. General and administrative expenses also include third-party costs such as legal costs, insurance costs, accounting, auditing and tax related fees, consulting fees and facilities and other expenses not otherwise included as research and development expenses. General and administrative costs are expensed as incurred. Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842 - Leases effective January 1, 2020 . The Company determines if an arrangement contains a lease at inception. The Company performed an evaluation of contracts in accordance with ASC 842 and has determined it has an operating lease agreement for the laboratory and office facilities that the Company occupies. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for the Company’s use. Operating lease liabilities are based on the present value of the future minimum lease payments over the lease term. ROU assets are measured at the amount of the lease liability, adjusted for any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As the Company’s leases generally do not provide an implicit interest rate, the present value of the future minimum lease payments is determined using the Company’s incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate the Company would incur on its future lease payments over a similar term and is based on the information available to the Company at the lease commencement date. The Company’s leases contain options to extend the leases; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreements do not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate non-lease components from lease components, to the extent they are fixed. Non-lease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable non-lease components, such as common-area maintenance costs. The Company has elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The Company accounts for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term. Lease expense is recognized within operating expenses on a straight-line basis over the terms of the lease. Incentives granted under the Company’s facilities lease, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the term of the lease. Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option and restricted stock unit grants subject to performance-based milestone vesting over the remaining implicit service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In assessing the Company’s ability to realize deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences are deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future income, tax planning strategies in making this assessment. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for incomes taxes. Comprehensive Loss Attributable to Common Stockholders Comprehensive loss attributable to common stockholders consists of net loss and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net loss. The Company’s comprehensive loss attributable to common stockholders is comprised of net loss and unrealized gains and losses on available-for-sale securities. Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company. Foreign Currency Transaction Remeasurement Adjustments Monetary assets and liabilities denominated in foreign currencies were translated into U.S. dollars, the reporting currency, at the exchange rate prevailing at the balance sheet date. Income and expenses denominated in foreign currencies were translated into U.S. dollars at the average exchange rate for the period and the transaction remeasurement adjustments are reported within other income, net in the consolidated statement of operations and comprehensive loss. The functional currency of the Company’s Australian subsidiary is the U.S. dollar. Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company and (2) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act, unless early adoption is permitted. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The Company adopted ASU 2016-13 effective January 1, 2023 and it did no t have a material impact on its financial condition, results of operations or cash flows.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value	3 . Fair Value The Company has certain assets and liabilities that are measured at fair value on a recurring basis according to a fair value hierarchy that prioritizes the inputs, assumptions and valuation techniques used to measure fair value. The three levels of the fair value hierarchy are: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 —Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly. Level 3 —Inputs are generally unobservable and reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are determined using model-based techniques, including probability-based simulation methodologies. The determination of a financial instrument’s level within the fair value hierarchy is based on an assessment of the lowest level of any input that is significant to the fair value measurement. The Company considers observable data to be market data, which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The following tables reflect the Company’s financial asset balances measured at fair value on a recurring basis (in thousands): December 31, 2023 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 63 $ — $ — $ 63 Commercial paper 2 59,227 — ( 30 ) 59,197 Total cash equivalents $ 59,290 $ — $ ( 30 ) $ 59,260 Short-term investments: Commercial paper 2 6,431 — ( 4 ) 6,427 U.S. government debt and agency 2 50,723 — ( 315 ) 50,408 Total short-term investments $ 57,154 $ — $ ( 319 ) $ 56,835 December 31, 2022 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 7 $ — $ — $ 7 Commercial paper 2 78,028 — ( 26 ) 78,002 Total cash equivalents $ 78,035 $ — $ ( 26 ) $ 78,009 Short-term investments: Commercial paper 2 36,933 — ( 168 ) 36,765 U.S. government debt and agency 2 65,157 — ( 784 ) 64,373 Corporate bonds 2 3,302 — ( 62 ) 3,240 Total short-term investments $ 105,392 $ — $ ( 1,014 ) $ 104,378 Long-term investments: U.S. government debt and agency 2 45,745 — ( 916 ) 44,829 Total long-term investments $ 45,745 $ — $ ( 916 ) $ 44,829 All the commercial paper, U.S. government debt, and agency securities, U.S. treasury bills, and corporate bonds designated as short-term investments have an effective maturity date that is equal to or less than one year from the respective balance sheet date. Those that are designated as long-term investments have an effective maturity date that is more than one year , but less than two years , from the respective balance sheet date. As of December 31, 2023, the Company does not intend to sell any securities in unrealized loss positions, and it is not more-likely-than-not that the Company will be required to sell such securities prior to the recovery of the amortized cost basis. Based on the Company's assessment, the Company concluded all impairments as of December 31, 2023 to be due to factors other than credit loss, such as changes in interest rates. A credit loss allowance was not recognized and the unrealized gains (losses) for available-for-sale securities were recorded in other comprehensive loss.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net Property and equipment consisted of the following (in thousands): December 31, 2023 2022 Lab equipment $ 688 $ 433 Office furniture, fixtures, and 712 692 Leasehold improvement 4,322 4,296 Property and equipment, at cost 5,722 5,421 Less: accumulated depreciation ( 2,334 ) ( 1,368 ) Property and equipment, net $ 3,388 $ 4,053 Depreciation expense was $ 969,000 and $ 845,000 for the years ended December 31, 2023 and 2022, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Liabilities	5 . Accrued Liabilities Accrued liabilities consisted of the following (in thousands): December 31, 2023 2022 Research and development expenses $ 11,916 $ 3,843 Employee compensation and benefits 4,545 3,415 Professional services and other 1,882 1,346 Total accrued liabilities $ 18,343 $ 8,604

Significant Agreements

Significant Agreements	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Agreements	6 . Significant Agreements WSU License Agreement The Company is party to an amended and restated exclusive license agreement with sublicensing terms with WSU that the Company entered into in 2015. Under this agreement, the Company has an exclusive license to make, use, sell, and offer for sale products covered by certain licensed patents, including dihexa, the chemical compound into which fosgonimeton metabolizes following administration. To keep in good standing, the agreement requires the Company to meet certain development milestones and pay annual maintenance fees. All contractual requirements have been met as of December 31, 2023. During the year ended December 31, 2020, the Phase 2 clinical trial milestone had been reached and a payment of $ 50,000 to WSU was recorded. The Company may also be obligated to pay the following if the related milestones are reached: • $ 300,000 – At initiation of the first Phase 3 clinical trial in the United States, European Union or Japan for the first licensed product; and • $ 600,000 – Upon receipt of marketing approval in the United States, European Union or Japan for the first licensed product. Under the terms of the agreement, the Company will pay a royalty in the mid-single digits of net sales, with the first $ 100,000 of net sales being exempt from royalty payment, and annual minimum royalty payments of $ 25,000 beginning after the first commercial sale of a licensed product. As of December 31, 2023, no sales of any licensed products had occurred and the Company had no t incurred a royalty obligation under this agreement. Additionally, the agreement allows the Company to sublicense the rights conveyed by the agreement, subject to additional payments to WSU based upon the sublicense consideration received in such event. Such amounts are dependent on the terms of the underlying sublicense and range from the mid-single digits to mid-teens of any non-sales based payments received, and low twenties of net sales based sublicense royalties. As of December 31, 2023, the Company has not entered into or incurred any liability from a sublicense agreement.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Legal Proceedings From time to time, the Company is subject to various legal proceedings or claims that arise in the ordinary course of business. The Company accrues a liability when the Company's management believes that it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated. The following is a brief description of the more significant legal proceedings. Securities Class Actions On June 25, 2021 , plaintiffs Fan Wang and Hang Gao filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company and the Company’s former chief executive officer Dr. Leen Kawas, captioned Wang v. Athira Pharma, Inc., et al. , No. 2:21-cv-00861. Plaintiffs Wang and Gao assert claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 ("Exchange Act") and SEC Rule 10b-5, alleging that the defendants made materially false and misleading statements and omitted material adverse facts regarding the Company’s business. Specifically, the Wang plaintiffs allege that the Company failed to disclose to investors that certain research conducted by Dr. Kawas was allegedly tainted by scientific misconduct during her doctoral work at WSU, including the manipulation of data, and that as a result, the defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading. The Wang plaintiffs seek unspecified compensatory and punitive damages, and reasonable costs and expenses, including attorneys’ fees. That same day, on June 25, 2021 , plaintiff Harshdeep Jawandha filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company, Dr. Kawas, the Company’s then chief financial officer, certain members of the Company’s board of directors at the time of the Company’s initial public offering ("IPO"), as well as the IPO underwriters, captioned Jawandha v. Athira Pharma, Inc., et al. , No. 2:21-cv-00862. The Jawandha complaint asserts violations of Sections 11 and 15 of the Securities Act of 1933 ("Securities Act"), alleging that that the Company’s IPO registration statement was materially false and misleading because it omitted to state that certain of Dr. Kawas’s published doctoral research papers at WSU contained allegedly improperly altered images, that the research was allegedly foundational to the Company’s efforts to develop treatments for Alzheimer’s disease, and that the defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading. The Jawandha plaintiff seeks unspecified compensatory damages, and reasonable costs and expenses, including attorneys’ fees. Also on June 25, 2021 , plaintiffs Timothy Slyne and Tai Slyne filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company, Dr. Kawas, the Company’s then chief financial officer, and the same members of the Company’s board of directors and underwriters as in the Jawandha complaint, captioned Slyne v. Athira Pharma, Inc. et al. , No. 2:21-cv-00864. The Slyne complaint asserts violations of Sections 11 and 15 of the Securities Act, alleging that purported issues with Dr. Kawas’s doctoral research at WSU should have been disclosed in the Company’s IPO registration statement. The Slyne plaintiffs seek unspecified compensatory damages, reasonable costs and expenses, including attorneys’ fees, and injunctive and other equitable relief. On August 9, 2021, the court issued an order consolidating the three cases. On October 5, 2021, the district court issued an order appointing lead plaintiffs and approved their selection of lead and liaison counsel. On January 7, 2022, lead plaintiffs filed a consolidated amended complaint, which asserts violations of Sections 10(b) and 20(a) of the Exchange Act and SEC Rule 10b-5 and Sections 11, 12, and 15 of the Securities Act. The consolidated amended complaint is brought against the Company, Dr. Kawas, the Company’s then chief financial officer, certain members of the Company's board of directors at the time of the Company's IPO and secondary public offering ("SPO"), and the IPO and SPO underwriters. As with the previous complaints, it is based on allegations that the IPO and SPO registration statements and/or other public statements were materially false and misleading because they omitted to state that certain of Dr. Kawas’s published doctoral research papers at WSU contained allegedly improperly altered images. Lead plaintiffs seek unspecified compensatory damages, as well as equitable and injunctive relief on behalf of themselves and the purported class. On March 8, 2022, the defendants filed a motion to dismiss lead plaintiffs’ consolidated amended complaint for failure to state a claim under the federal securities laws. On July 29, 2022, the court issued an order granting in part and denying in part the motion to dismiss. The order dismissed the Section 10(b) and Section 20(a) claims arising under the Exchange Act, dismissed the Section 11 claim arising under the Securities Act as to all defendants other than the Company and Dr. Kawas, dismissed the Section 12(a)(2) claim arising under the Securities Act as to the lead plaintiffs, and dismissed the Section 15 claim arising under the Securities Act against all defendants other than Dr. Kawas. The order permitted lead plaintiffs until August 19, 2022 to file a second consolidated amended complaint. Lead plaintiffs did not file a second consolidated amended complaint. On August 12, 2022 , defendant Dr. Kawas filed a motion for partial reconsideration of the court’s July 29, 2022 order. On October 24, 2022, the parties filed a (1) joint status report and discovery plan and (2) stipulation and case scheduling order, wherein the parties proposed deadlines for material case events, including the completion of fact discovery, expert discovery, and dispositive motion practice. On November 2, 2022, the court entered an order setting certain case deadlines. On November 4, 2022, the Company and Dr. Kawas filed their individual answers to the consolidated amended complaint. In mid-November 2022, the parties began conducting fact discovery. On March 10, 2023, following a mediation and the parties’ agreement in principle to settle the securities class action, the court entered a stipulated order setting a deadline of April 28, 2023 for the parties to file a stipulation of settlement and for lead plaintiffs to file a motion for preliminary approval of the settlement, which the parties filed on that date. The settlement is subject to preliminary and final approval by the U.S. District Court for the Western District of Washington. On May 31, 2023, the court issued a minute order requiring the parties to file a joint status report on or before June 30, 2023 addressing several aspects of the proposed settlement, including revision of certain notices to putative class members regarding the settlement, which the parties filed on that date. On September 27, 2023, the court issued an order denying plaintiffs’ motion for preliminary approval without prejudice, citing the motion’s failure to satisfy the court’s questions and concerns regarding traceability of certain Securities Act claims. The court permitted plaintiffs to file a renewed motion for preliminary approval, which plaintiffs filed on December 15, 2023. On February 15, 2024, the court issued an order granting in part and deferring in part plaintiffs’ renewed motion for preliminary approval and ordered the parties to submit a joint status report by March 15, 2024 proposing a date on which the court may schedule the final approval hearing, among other things. In its order, the court preliminarily approved the proposed settlement and certified a class and two subclasses. The court deferred ruling in part as to the proposed notices and claim form relating to the settlement. As a result of the foregoing, the Company recorded a legal settlement expense of $ 10.0 million in operating expenses in the fourth quarter of 2022 and an accrued liability of $ 10.0 million on the accompanying consolidated balance sheets. Additionally, the Company recorded an insurance recovery of $ 1.6 million in operating expenses in the fourth quarter of 2023 and an insurance recovery receivable of $ 1.6 million on the accompanying consolidated balance sheets. This insurance recovery represents the amount of the settlement to be covered by the Company's insurers. Shareholder Derivative Actions On April 14, 2022, a shareholder derivative action was filed by plaintiff Stephen Bushansky in the U.S. District Court for the Western District of Washington against certain current and former members of the Company’s board of directors, captioned Bushansky v. Kawas et al. , No. 2:22-cv-497. Plaintiff purports to bring the action derivatively on behalf of the Company, which is a nominal defendant to the action. The derivative complaint alleges that the Company’s board of directors breached its fiduciary duties by failing to prevent alleged misstatements in the Company’s public filings, failing to discover altered images in certain research papers, and failing to take appropriate action. The derivative complaint asserts claims for violations of Section 14(a) of the Exchange Act as well as claims for breach of fiduciary duty, contribution and indemnification, aiding and abetting, and waste of corporate assets. The derivative complaint seeks unspecified damages, disgorgement of profits, benefits, and other compensation received by the individual defendants, restitution, declaratory relief, and an award of costs and expenses to the derivative plaintiff, including attorneys’ fees. On May 6, 2022, a second shareholder derivative action was filed by plaintiff Thomas Houlihan in the U.S. District Court for the Western District of Washington against certain current and former directors and officers of the Company, captioned Houlihan v. Kawas et al ., No. 2:22-cv-620. Plaintiff purports to bring the action derivatively on behalf of the Company, which is a nominal defendant to the action. The derivative complaint alleges that certain of the Company’s current and former directors and officers breached their fiduciary duties by failing to prevent alleged misstatements in the Company’s public filings and failing to take appropriate action regarding altered images in certain research papers. The derivative complaint asserts claims for violations of Section 14(a) of the Exchange Act as well as claims for breach of fiduciary duties, contribution, and indemnification. The derivative complaint seeks unspecified damages, unspecified corporate governance reforms, restitution, and an award of costs and expenses to the derivative plaintiff, including attorneys’ fees. On May 26, 2022, the court issued an order consolidating the cases and staying them until further order of the court. The Company believes it has adequate reserves related to this matter as of the latest balance sheet date. Government Investigations In November 2022, the Company received a Civil Investigative Demand from the Civil Division of the Department of Justice (the "Demand"). The Demand seeks documents and information relating to our relationship with WSU, certain of our grant applications in 2016 and 2019 with the NIH, and our receipt of a NIH grant in 2020. The Company is cooperating with the Department of Justice with respect to the Demand. In February 2023, the Securities and Exchange Commission ("SEC"), sent the Company a subpoena seeking documents and information relating to, among other things, the Company's former chief executive officer's alterations of images in certain research papers. The Company is cooperating with the SEC with respect to the subpoena. The Company cannot predict the outcome of these lawsuits or government investigations. Failure by the Company to obtain a favorable resolution of these actions could have a material adverse effect on our business, results of operations and financial condition. Indemnifications 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. To date the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company enters 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. Operating Leases The Company has operating leases for laboratory and office facilities in Bothell, Washington that expire in August 2027 . The initial terms of the leases range from 6.3 to 7 years and the Company has options to extend the leases for an additional five years that it is not reasonably certain to exercise. As of December 31, 2023, the Company was not party to any finance leases. The following table reconciles the Company’s undiscounted operating lease cash flows to its operating lease liability (in thousands): December 31, 2024 480 2025 494 2026 509 Thereafter 346 Total undiscounted lease payments 1,829 Present value adjustment for minimum lease ( 244 ) Net lease liability $ 1,585 The weighted average remaining lease term and the weighted average discount rate used to determine the operating lease liability were as follows: December 31, Weighted average remaining lease term (years) 3.7 Weighted average discount rate 8.1 % Operating lease expense was $ 353,000 and $ 368,000 for the years ended December 31, 2023 and 2022, respectively. Separately, variable lease expense was $ 186,000 and $ 167,000 for operating leases during the years ended December 31, 2023 and 2022, respectively.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Common Stock	8 . Common Stock Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and if declared by the Company’s board of directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the board of directors from inception. The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: December 31, 2023 2022 Shares issuable upon the exercise of outstanding 7,130,956 4,269,861 Shares available for future grant under the 2020 3,158,094 4,253,854 Shares available for future grant under the 1,128,732 916,640 Total 11,417,782 9,440,355 The Company’s 2020 Equity Incentive Plan (“2020 Plan”) provides for annual increases in the number of shares that may be issued under the 2020 Plan on January 1, 2021 and each subsequent January 1, thereafter, by a number of shares equal to the least of (1) 3,230,000 shares, (2) 5 % of the number of shares of common stock issued and outstanding on the immediately preceding December 31, and (3) an amount determined by the Company’s board of directors. The Company’s 2020 Employee Stock Purchase Plan (“ESPP”) provides for annual increases in the number of shares that may be issued under the ESPP on January 1, 2021 and each subsequent January 1, thereafter, by a number of shares equal to the least of (1) 646,000 shares, (2) 1 % of the number of shares of common stock issued and outstanding on the immediately preceding December 31, and (3) an amount determined by the Company’s board of directors. Effective January 1, 2023, the Company’s 2020 Plan and ESPP reserves increased by 1,893,869 shares and 378,774 shares, respectively. Effective January 1, 2024, the Company’s 2020 Plan and ESPP reserves increased by 1,908,630 shares and 381,726 shares, respectively.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	9 . Stock-based Compensation Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2023 2022 Research and development $ 4,003 $ 3,217 General and administrative 6,620 7,389 Total stock-based compensation expense $ 10,623 $ 10,606 Valuation Assumptions The fair value of stock options was determined using the Black-Scholes option-pricing model and the assumptions below. Each of these inputs is subjective and generally required significant judgment. • Fair Value of Common Stock —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, or other relevant determination date, as reported on The Nasdaq Global Select Market. • Risk-Free Interest Rate —The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the option. • Expected Volatility —Because the Company was previously privately held and did not have any trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded life sciences companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in life cycle or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. • Expected Term —The expected term represents the period that the stock-based awards are expected to be outstanding and is determined using the simplified method (based on the midpoint between the vesting date and the end of the contractual term) as the Company has limited history of relevant stock option exercise activity. • Expected Dividend Yield —The Company has never paid dividends on its common stock and has no plans to pay dividends going forward. Therefore, it used an expected dividend yield of zero . The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Year Ended December 31, 2023 2022 Risk-free interest rate 3.54 % 2.15 % Expected volatility 99.18 % 92.95 % Expected term (in years) 5.84 6.02 Expected dividend yield — — The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. The fair value of options granted during the years ended December 31, 2023 and 2022 were $ 9.8 million and $ 16.3 million, respectively. The fair value of restricted stock units granted during the year ended December 31, 2023 and 2022 was $ 0.5 million and $ 0.1 million, respectively. Stock Option Activity Changes in shares available for grant under the 2020 Plan during the year ended December 31, 2023 were as follows: Shares Shares available for grant at December 31, 2022 4,253,854 2020 Plan reserve increase on January 1, 2023 1,893,869 Options and restricted stock units granted ( 3,834,783 ) Options and restricted stock units forfeited, 845,154 Shares available for grant at December 31, 2023 3,158,094 A summary of option activity for the year ended December 31, 2023 was as follows: Shares Weighted- Weighted- Aggregate Balance at December 31, 2022 4,033,522 $ 11.75 8.40 $ 827 Granted 3,696,783 3.34 Exercised ( 128,534 ) 1.29 Forfeited/expired ( 780,902 ) 6.72 Balance at December 31, 2023 6,820,869 $ 7.97 8.24 $ 387 Expected to vest 4,000,554 $ 6.41 8.72 $ — Options exercisable 2,820,315 $ 10.18 7.56 $ 387 The total fair value of options granted that vested during the years ended December 31, 2023 and 2022 was $ 9.8 million and $ 6.8 million, respectively. The aggregate intrinsic value in the table above is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the Company’s common stock underlying all options that were in-the-money at December 31, 2023. The aggregate intrinsic value of options exercised was $ 0.2 million and $ 3.0 million during the year ended December 31, 2023 and 2022, respectively, determined as of the date of option exercise. As of December 31, 2023, there was $ 16.0 million of total unrecognized compensation cost related to non-vested stock options. The Company expects to recognize this cost over a remaining weighted-average period of 1.99 years. The Company utilizes newly issued shares to satisfy option exercises. Stock options outstanding and exercisable consisted of the following at December 31, 2023: Exercise Price ($) Shares Shares 0.16 to 4.22 3,709,593 1,005,785 8.93 to 19.94 2,759,028 1,615,758 20.55 to 29.41 352,248 198,772 Total 6,820,869 2,820,315 Restricted Stock Unit Activity A summary of RSU activity for the year ended December 31, 2023 is as follows: Share Weighted- Non-vested at December 31, 2022 236,339 $ 15.16 Granted 138,000 3.28 Cancelled ( 64,252 ) 7.63 Vested — — Non-vested at December 31, 2023 310,087 $ 11.44 Employee Stock Purchase Plan Under the ESPP, eligible employees can authorize payroll deductions for amounts up to the lesser of 15 % of their qualifying wages or the statutory limit under the U.S. Internal Revenue Code. The ESPP provides for offering periods of six months in duration with one purchase period per offering period beginning May 18 and November 18 of each year. Participants in an offering period will be granted the right to purchase shares of our common stock at a price per share that is 85 % of the lesser of the fair market value of the shares at (1) the first day of the offering period or (2) the end of each purchase period within the offering period. A maximum of 10,000 shares of common stock may be purchased by each participant at the purchase date during the offering period. The fair market value of the ESPP options granted is determined using the Black-Scholes model and is amortized on a straight-line basis. Stock-based compensation expense recognized during the years ended December 31, 2023 and 2022 associated with the ESPP was $ 0.1 million and $ 0.2 million, respectively. During the year ended December 31, 2023, the Company issued 166,682 shares of common stock to employees under the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes Components of Income and Income Tax The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2023 and 2022. Net loss is attributable to the following tax jurisdictions (in thousands): Year Ended December 31, 2023 2022 United States $ ( 117,440 ) $ ( 95,778 ) Foreign ( 232 ) 139 Net Loss $ ( 117,672 ) $ ( 95,639 ) The provision for income taxes differs from the amount expected by applying the federal statutory rates to the net loss before taxes as follows: Year Ended December 31, 2023 2022 Federal statutory income tax rate 21.0 % 21.0 % State taxes — ( 0.4 ) Stock-based compensation ( 1.1 ) ( 1.3 ) Non-deductible expenses and others ( 0.1 ) ( 0.1 ) Tax credits 4.2 2.2 Change in valuation allowance ( 24.0 ) ( 21.4 ) Effective income tax rate — % — % Deferred Tax Assets and Liabilities The components of the Company’s deferred tax assets and liabilities were as follows (in thousands): Year Ended December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 31,342 $ 24,092 Research and development tax credit 9,327 4,218 Accrued liabilities 2,828 2,781 Stock-based compensation 2,564 1,676 Operating lease liability 333 404 Other 180 121 Capitalized research and development 25,182 10,729 Total deferred tax assets 71,756 44,021 Deferred tax liabilities: Right of use asset ( 221 ) ( 267 ) Prepaid expenses and other ( 75 ) ( 475 ) Investments ( 214 ) ( 294 ) Total deferred tax liabilities ( 510 ) ( 1,036 ) Less valuation allowance ( 71,246 ) ( 42,985 ) Net deferred tax assets $ — $ — Deferred income taxes reflect temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes, and operating losses and tax credit carryforwards. The Company considers a number of factors concerning the realizability of its net deferred tax assets, including its history of operating losses, the nature of the deferred tax assets, and the timing, likelihood and amount, if any, of future taxable income during the periods in which those temporary differences and carryforwards become deductible, all of which require significant judgment. As of December 31, 2023, the Company has recorded a full valuation allowance on its net deferred tax assets as the Company has concluded that it is not more likely than not that such losses or credits will be utilized. The valuation allowance increased by $ 28.3 million and $ 20.4 million during 2023 and 2022, respectively. At December 31, 2023, the Company has federal net operating loss and tax credit carryforwards of $ 9.5 million and $ 12.4 million, respectively, which expire over a period of 8 to 14 years. Net operating loss carryforwards of $ 138.7 million were generated after 2017, and therefore do not expire. As of December 31, 2023, the Company also had state net operating loss carryforwards of $ 3.3 million, which expire over a period of 18 to 20 years. The Tax Cuts and Jobs Act contained a provision which requires the capitalization of Section 174 costs incurred in years beginning on or after January 1, 2022. Section 174 costs are expenditures which represent research and development costs that are incident to the development or improvement of a product, process, formula, invention, computer software, or technique. This provision changes the treatment of Section 174 costs such that the expenditures are no longer allowed as an immediate deduction but rather must be capitalized and amortized. We have included the impact of this provision, which results in a deferred tax asset of approximately $ 25.2 million as of December 31, 2023. Uncertain Tax Positions The Company files federal income tax returns. With few exceptions, the Company is no longer subject to income tax examinations by tax authorities for years prior to 2016. However, to the extent allowed by law, the tax authorities may have the right to examine prior periods where net operating losses or tax credits were generated and carried forward and may make adjustments to the amount of the net operating loss or credit carryforward amount. The Company is not currently under examination in any jurisdiction. A reconciliation of the beginning and ending amount of unrecognized tax benefits for uncertain tax positions were as follows (in thousands): Year Ended December 31, 2023 2022 Beginning balance $ 1,406 $ 722 Additions for tax positions taken in prior 182 - Additions for tax positions taken in the current 1,521 684 Ending balance $ 3,109 $ 1,406 If the unrecognized tax benefits for uncertain tax positions as of December 31, 2023 are recognized, there will be no impact to the effective tax rate due to the valuation allowance. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying consolidated financial statements. At December 31, 2023, there were no material interest and penalties on uncertain tax benefits. The Company does not anticipate any significant changes to its unrecognized tax benefits in the next 12 months.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2023
Employee Benefit Plans [Abstract]
Employee Benefit Plans	11. Employee Benefit Plans The Company has a 401(k) Plan for all of its employees. The 401(k) Plan allows eligible employees to defer, at the employee’s discretion, up to 100 % of their pretax compensation up to the Internal Revenue Service annual limit. The Company made matching contributions of $ 0.5 million and $ 0.4 million during the years ended December 31, 2023 and 2022, respectively.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	12. 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: Year Ended December 31, 2023 2022 Stock options to purchase common stock 6,820,869 4,033,522 Non-vested Restricted Stock Units 310,087 236,339 Employee stock purchase plan 3,495 5,148 Total 7,134,451 4,275,009

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). The consolidated financial statements include the operations of Athira Pharma, Inc., and its wholly owned Australian subsidiary. All intercompany balances and transactions have been eliminated upon consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related 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.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers highly liquid investments with original maturities of three months or less to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash consists primarily of collateral pledged in connection with the Company's corporate credit cards. The table below reconciles the balances of cash and cash equivalents and restricted cash reported on the consolidated balance sheets to the balances of cash, cash equivalents and restricted cash reported on the consolidated statements of cash flows. December 31, 2023 2022 Cash and cash equivalents $ 90,584 $ 95,966 Restricted cash 631 420 Cash, cash equivalents and restricted cash $ 91,215 $ 96,386
Short-term and Long-term Investments	Short-term and Long-term Investments The Company generally invests its excess cash in investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term investments, and long-term investments on the consolidated balance sheets, classified as available-for-sale, and reported at fair value with unrealized gains and losses included in accumulated other comprehensive loss. Amortization and accretion are included in other income, net. Realized gains and losses on the sale of these securities are recognized in other income, net. The Company periodically evaluates whether declines in fair values of its investments below their book value are due to expected credit losses, as well as the Company's ability and intent to hold the investment until a forecasted recovery occurs. Expected credit losses are recorded as an allowance through other income, net.
Concentration of Credit Risk	Concentration of Credit Risk The Company is exposed to credit risk from its deposits of cash in excess of amounts insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses on its deposits of cash since inception.
Property and Equipment	Property and Equipment Property and equipment consist of computer equipment, computer software, laboratory equipment, leasehold improvements and furniture and office equipment. Property and equipment, excluding leasehold improvements, are recorded at cost and depreciation is recognized using the straight-line method based on estimated useful life, generally three to five years . Leasehold improvements are amortized over the shorter of their useful life or the remaining lease term. Maintenance and repairs are charged to expense as incurred, and costs of improvements are capitalized. The Company reviews long-lived assets for impairment whenever events or circumstances indicate the carrying amount of an asset group may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset's carrying amount over its fair value. Gains and losses from asset disposals and impairment losses are classified within the consolidated statements of operations and comprehensive loss in accordance with the use of the asset. There were no impairment losses in the years ended December 31, 2023 and 2022 as there have been no events warranting an impairment analysis.
Fair Value Measurements	Fair Value Measurements The carrying amounts of certain financial instruments, including cash, cash equivalents, restricted cash, investments, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts.
Grant Income	Grant Income In December 2020, the Company accepted a grant from the National Institute on Aging (“NIA”) of the National Institutes of Health (“NIH”) to support its ACT-AD Phase 2 clinical trial for fosgonimeton (then-named ATH-1017), the Company’s lead therapeutic candidate being developed for the treatment of individuals with mild-to-moderate Alzheimer’s disease. The Company recognizes income related to the NIH grant in the accompanying consolidated statements of operations and comprehensive loss as qualifying expenses under the grant agreement are incurred. As of December 31, 2023, the Company has recognized aggregate grant income of $ 15.2 million in connection with the NIH grant, equal to the total grant amount approved. The Company will no t recognize any additional grant income in connection with the NIH grant in the future. During the years ended December 31, 2023 and 2022, the Company recognized grant income of $ 0.2 million and $ 5.2 million, respectively, in connection with the NIH grant. As of December 31, 2022, the Company incurred qualifying expenses in excess of cash received of $ 1.2 million, which is included in unbilled grant receivable on the consolidated balance sheets. The Company received cash of $ 1.4 million related to the NIH grant during the year ended December 31, 2023, compared to $ 6.3 million during the year ended December 31, 2022.
Research and Development Expenses	Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of the pipeline from the Company’s proprietary drug discovery platform (“ATH platform”), the Company’s drug discovery efforts and the development of its drug candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expensed when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company adjusts the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception.
General and Administrative Expenses	General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs, consisting of employee salaries, related benefits, and stock-based compensation expense for employees in the executive, legal, finance and accounting, human resources, and other administrative functions. General and administrative expenses also include third-party costs such as legal costs, insurance costs, accounting, auditing and tax related fees, consulting fees and facilities and other expenses not otherwise included as research and development expenses. General and administrative costs are expensed as incurred.
Leases	Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842 - Leases effective January 1, 2020 . The Company determines if an arrangement contains a lease at inception. The Company performed an evaluation of contracts in accordance with ASC 842 and has determined it has an operating lease agreement for the laboratory and office facilities that the Company occupies. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for the Company’s use. Operating lease liabilities are based on the present value of the future minimum lease payments over the lease term. ROU assets are measured at the amount of the lease liability, adjusted for any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As the Company’s leases generally do not provide an implicit interest rate, the present value of the future minimum lease payments is determined using the Company’s incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate the Company would incur on its future lease payments over a similar term and is based on the information available to the Company at the lease commencement date. The Company’s leases contain options to extend the leases; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreements do not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate non-lease components from lease components, to the extent they are fixed. Non-lease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable non-lease components, such as common-area maintenance costs. The Company has elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The Company accounts for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term. Lease expense is recognized within operating expenses on a straight-line basis over the terms of the lease. Incentives granted under the Company’s facilities lease, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the term of the lease.
Stock-based Compensation	Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option and restricted stock unit grants subject to performance-based milestone vesting over the remaining implicit service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In assessing the Company’s ability to realize deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences are deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future income, tax planning strategies in making this assessment. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for incomes taxes.
Comprehensive Loss Attributable to Common Stockholders	Comprehensive Loss Attributable to Common Stockholders Comprehensive loss attributable to common stockholders consists of net loss and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net loss. The Company’s comprehensive loss attributable to common stockholders is comprised of net loss and unrealized gains and losses on available-for-sale securities.
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company.
Foreign Currency Transaction Remeasurement Adjustments	Foreign Currency Transaction Remeasurement Adjustments Monetary assets and liabilities denominated in foreign currencies were translated into U.S. dollars, the reporting currency, at the exchange rate prevailing at the balance sheet date. Income and expenses denominated in foreign currencies were translated into U.S. dollars at the average exchange rate for the period and the transaction remeasurement adjustments are reported within other income, net in the consolidated statement of operations and comprehensive loss. The functional currency of the Company’s Australian subsidiary is the U.S. dollar.
Segments	Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources.
Emerging Growth Company Status	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company and (2) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act, unless early adoption is permitted. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recent Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The Company adopted ASU 2016-13 effective January 1, 2023 and it did no t have a material impact on its financial condition, results of operations or cash flows.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The table below reconciles the balances of cash and cash equivalents and restricted cash reported on the consolidated balance sheets to the balances of cash, cash equivalents and restricted cash reported on the consolidated statements of cash flows. December 31, 2023 2022 Cash and cash equivalents $ 90,584 $ 95,966 Restricted cash 631 420 Cash, cash equivalents and restricted cash $ 91,215 $ 96,386

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments	The following tables reflect the Company’s financial asset balances measured at fair value on a recurring basis (in thousands): December 31, 2023 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 63 $ — $ — $ 63 Commercial paper 2 59,227 — ( 30 ) 59,197 Total cash equivalents $ 59,290 $ — $ ( 30 ) $ 59,260 Short-term investments: Commercial paper 2 6,431 — ( 4 ) 6,427 U.S. government debt and agency 2 50,723 — ( 315 ) 50,408 Total short-term investments $ 57,154 $ — $ ( 319 ) $ 56,835 December 31, 2022 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 7 $ — $ — $ 7 Commercial paper 2 78,028 — ( 26 ) 78,002 Total cash equivalents $ 78,035 $ — $ ( 26 ) $ 78,009 Short-term investments: Commercial paper 2 36,933 — ( 168 ) 36,765 U.S. government debt and agency 2 65,157 — ( 784 ) 64,373 Corporate bonds 2 3,302 — ( 62 ) 3,240 Total short-term investments $ 105,392 $ — $ ( 1,014 ) $ 104,378 Long-term investments: U.S. government debt and agency 2 45,745 — ( 916 ) 44,829 Total long-term investments $ 45,745 $ — $ ( 916 ) $ 44,829

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, 2023 2022 Lab equipment $ 688 $ 433 Office furniture, fixtures, and 712 692 Leasehold improvement 4,322 4,296 Property and equipment, at cost 5,722 5,421 Less: accumulated depreciation ( 2,334 ) ( 1,368 ) Property and equipment, net $ 3,388 $ 4,053

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): December 31, 2023 2022 Research and development expenses $ 11,916 $ 3,843 Employee compensation and benefits 4,545 3,415 Professional services and other 1,882 1,346 Total accrued liabilities $ 18,343 $ 8,604

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Reconciliation of Undiscounted Operating Lease Cash Flows to Operating Lease Liability Payments	The following table reconciles the Company’s undiscounted operating lease cash flows to its operating lease liability (in thousands): December 31, 2024 480 2025 494 2026 509 Thereafter 346 Total undiscounted lease payments 1,829 Present value adjustment for minimum lease ( 244 ) Net lease liability $ 1,585
Weighted Average Remaining Lease Term and Weighted Average Discount Rate to Determine the Operating Lease Liability	The weighted average remaining lease term and the weighted average discount rate used to determine the operating lease liability were as follows: December 31, Weighted average remaining lease term (years) 3.7 Weighted average discount rate 8.1 %

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Reserved Shares of Common Stock for Future Issuance	The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: December 31, 2023 2022 Shares issuable upon the exercise of outstanding 7,130,956 4,269,861 Shares available for future grant under the 2020 3,158,094 4,253,854 Shares available for future grant under the 1,128,732 916,640 Total 11,417,782 9,440,355

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based Compensation Expense Recognized	Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2023 2022 Research and development $ 4,003 $ 3,217 General and administrative 6,620 7,389 Total stock-based compensation expense $ 10,623 $ 10,606
Weighted-Average Assumptions used in Estimating Fair Value of each Stock Options using Black-Scholes Option-Pricing Model	The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Year Ended December 31, 2023 2022 Risk-free interest rate 3.54 % 2.15 % Expected volatility 99.18 % 92.95 % Expected term (in years) 5.84 6.02 Expected dividend yield — —
Summary of Option Activity Changes in Shares Available for Grant under the 2020 Plan	Changes in shares available for grant under the 2020 Plan during the year ended December 31, 2023 were as follows: Shares Shares available for grant at December 31, 2022 4,253,854 2020 Plan reserve increase on January 1, 2023 1,893,869 Options and restricted stock units granted ( 3,834,783 ) Options and restricted stock units forfeited, 845,154 Shares available for grant at December 31, 2023 3,158,094
Summary of Option Activity	A summary of option activity for the year ended December 31, 2023 was as follows: Shares Weighted- Weighted- Aggregate Balance at December 31, 2022 4,033,522 $ 11.75 8.40 $ 827 Granted 3,696,783 3.34 Exercised ( 128,534 ) 1.29 Forfeited/expired ( 780,902 ) 6.72 Balance at December 31, 2023 6,820,869 $ 7.97 8.24 $ 387 Expected to vest 4,000,554 $ 6.41 8.72 $ — Options exercisable 2,820,315 $ 10.18 7.56 $ 387
Summary of Stock Options Outstanding and Exercisable	Stock options outstanding and exercisable consisted of the following at December 31, 2023: Exercise Price ($) Shares Shares 0.16 to 4.22 3,709,593 1,005,785 8.93 to 19.94 2,759,028 1,615,758 20.55 to 29.41 352,248 198,772 Total 6,820,869 2,820,315
Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Restricted Stock Activity	A summary of RSU activity for the year ended December 31, 2023 is as follows: Share Weighted- Non-vested at December 31, 2022 236,339 $ 15.16 Granted 138,000 3.28 Cancelled ( 64,252 ) 7.63 Vested — — Non-vested at December 31, 2023 310,087 $ 11.44

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Tax	The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2023 and 2022. Net loss is attributable to the following tax jurisdictions (in thousands): Year Ended December 31, 2023 2022 United States $ ( 117,440 ) $ ( 95,778 ) Foreign ( 232 ) 139 Net Loss $ ( 117,672 ) $ ( 95,639 )
Schedule of Effective Income Tax Rate Reconciliation	The provision for income taxes differs from the amount expected by applying the federal statutory rates to the net loss before taxes as follows: Year Ended December 31, 2023 2022 Federal statutory income tax rate 21.0 % 21.0 % State taxes — ( 0.4 ) Stock-based compensation ( 1.1 ) ( 1.3 ) Non-deductible expenses and others ( 0.1 ) ( 0.1 ) Tax credits 4.2 2.2 Change in valuation allowance ( 24.0 ) ( 21.4 ) Effective income tax rate — % — %
Components of Deferred Tax Assets and Liabilities	The components of the Company’s deferred tax assets and liabilities were as follows (in thousands): Year Ended December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 31,342 $ 24,092 Research and development tax credit 9,327 4,218 Accrued liabilities 2,828 2,781 Stock-based compensation 2,564 1,676 Operating lease liability 333 404 Other 180 121 Capitalized research and development 25,182 10,729 Total deferred tax assets 71,756 44,021 Deferred tax liabilities: Right of use asset ( 221 ) ( 267 ) Prepaid expenses and other ( 75 ) ( 475 ) Investments ( 214 ) ( 294 ) Total deferred tax liabilities ( 510 ) ( 1,036 ) Less valuation allowance ( 71,246 ) ( 42,985 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits for Uncertain Tax Positions	A reconciliation of the beginning and ending amount of unrecognized tax benefits for uncertain tax positions were as follows (in thousands): Year Ended December 31, 2023 2022 Beginning balance $ 1,406 $ 722 Additions for tax positions taken in prior 182 - Additions for tax positions taken in the current 1,521 684 Ending balance $ 3,109 $ 1,406

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Summary of Dilutive Securities Excluded from Computation of Diluted 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: Year Ended December 31, 2023 2022 Stock options to purchase common stock 6,820,869 4,033,522 Non-vested Restricted Stock Units 310,087 236,339 Employee stock purchase plan 3,495 5,148 Total 7,134,451 4,275,009

Description of Business - Addit

Description of Business - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2023
Description Of Business [Line Items]
Entity incorporation, date of Incorporation		Mar. 31, 2011
Entity reincorporation, date of reincorporation		Oct. 27, 2015
Net cash proceeds from issuance of convertible preferred stock, common stock warrants, and convertible notes		$ 407.4
Cash, cash equivalents, and investments		$ 147.4
At The Market Common Stock Offering
Description Of Business [Line Items]
Number of shares issued and sold	0
At The Market Common Stock Offering | Maximum
Description Of Business [Line Items]
Aggregate proceeds from issuance of common stock	$ 75

Significant Accounting Polici_4

Significant Accounting Policies - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 90,584	$ 95,966
Restricted cash	631	420
Cash, cash equivalents and restricted cash	$ 91,215	$ 96,386	$ 110,537

Significant Accounting Polici_5

Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Impairment losses	$ 0	$ 0
Grant income	$ 157,000	5,161,000
Unbilled grant receivable		1,227,000
Change in accounting principle, accounting standards update, adopted	true
Accounting Standards Update [Extensible Enumeration]	us-gaap:AccountingStandardsUpdate201613Member
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
Number of operating segments | Segment	1
ASU 2016-02
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
National Institutes of Health Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grants received	$ 1,400,000	6,300,000
Grant income	200,000	5,200,000
Aggregate grant income	15,200,000
Additional grant income	$ 0
Unbilled grant receivable		$ 1,200,000
Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Property and equipment useful life	3 years
Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Property and equipment useful life	5 years

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	$ 90,584	$ 95,966
Recurring Basis | Short-term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	57,154	105,392
Investments, Unrealized Losses	(319)	(1,014)
Investments, Fair Value	56,835	104,378
Recurring Basis | Short-term Investments | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	6,431	36,933
Investments, Unrealized Losses	(4)	(168)
Investments, Fair Value	6,427	36,765
Recurring Basis | Short-term Investments | U.S. Government Debt and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	50,723	65,157
Investments, Unrealized Losses	(315)	(784)
Investments, Fair Value	50,408	64,373
Recurring Basis | Short-term Investments | Corporate Bonds | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost		3,302
Investments, Unrealized Losses		(62)
Investments, Fair Value		3,240
Recurring Basis | Long Term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost		45,745
Investments, Unrealized Losses		(916)
Investments, Fair Value		44,829
Recurring Basis | Long Term Investments | U.S. Government Debt and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost		45,745
Investments, Unrealized Losses		(916)
Investments, Fair Value		44,829
Recurring Basis | Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	59,290	78,035
Cash equivalents, Unrealized Losses	(30)	(26)
Cash equivalents, Fair Value	59,260	78,009
Recurring Basis | Cash Equivalents | Money Market Fund | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	63	7
Cash equivalents, Fair Value	63	7
Recurring Basis | Cash Equivalents | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	59,227	78,028
Cash equivalents, Unrealized Losses	(30)	(26)
Cash equivalents, Fair Value	$ 59,197	$ 78,002

Fair Value - Additional Informa

Fair Value - Additional Information (Details) - Recurring Basis	12 Months Ended
	Dec. 31, 2023
Minimum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term investments effective maturity date	1 year
Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Short-term investments effective maturity date	1 year
Long-term investments effective maturity date	2 years

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 5,722	$ 5,421
Less: accumulated depreciation	(2,334)	(1,368)
Property and equipment, net	3,388	4,053
Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	688	433
Office Furniture, Fixtures, and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	712	692
Leasehold Improvement
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 4,322	$ 4,296

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 969,000	$ 845,000

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Research and development expenses	$ 11,916	$ 3,843
Employee compensation and benefits	4,545	3,415
Professional services and other	1,882	1,346
Total accrued Liabilities	$ 18,343	$ 8,604

Significant Agreements - Additi

Significant Agreements - Additional Information (Details) - Washington State University License Agreement - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2020	Dec. 31, 2015
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments payable upon marketing approval			$ 600,000
Annual minimum royalty payments			25,000
Net sales exempt from royalty payment			100,000
Royalty obligation	$ 0
Licensed Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sales	$ 0
Phase 2 Clinical Trial Initiation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments on development milestone achieved		$ 50,000
Phase 3 Clinical Trial Initiation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments, amount payable			$ 300,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Commitments And Contingencies [Line Items]
Legal settlement expense		$ 10,000,000		$ 10,000,000
Insurance recovery in operating expenses	$ 1,600,000		$ 1,628,000
Insurance recovery receivable	1,628,000		1,628,000
Accrued legal settlement	$ 10,000,000	$ 10,000,000	10,000,000	10,000,000
Operating lease expense			353,000	368,000
Variable lease expense			$ 186,000	$ 167,000
Wang V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date			June 25, 2021
Name of plaintiff			Fan Wang and Hang Gao
Jawandha V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date			June 25, 2021
Name of plaintiff			Harshdeep Jawandha
Slyne V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date			June 25, 2021
Name of plaintiff			Timothy Slyne and Tai Slyne
Athira Pharma Inc V Dr. Kawas
Commitments And Contingencies [Line Items]
Lawsuit filing date			August 12, 2022
Name of defendant			Dr. Kawas
Laboratory and Office Facilities | Bothell, Washington
Commitments And Contingencies [Line Items]
Operating lease expiration month and year			2027-08
Operating lease existence of option to extend			true
Operating lease, additional term of contract	5 years		5 years
Laboratory and Office Facilities | Bothell, Washington | Minimum
Commitments And Contingencies [Line Items]
Operating lease initial term	6 years 3 months 18 days		6 years 3 months 18 days
Laboratory and Office Facilities | Bothell, Washington | Maximum
Commitments And Contingencies [Line Items]
Operating lease initial term	7 years		7 years

Commitments and Contingencies_2

Commitments and Contingencies - Reconciliation of Undiscounted Operating Lease Cash Flows to Operating Lease Liability Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2024	$ 480
2025	494
2026	509
Thereafter	346
Total undiscounted lease payments	1,829
Present value adjustment for minimum lease commitments	(244)
Net lease liability	$ 1,585

Commitments and Contingencies_3

Commitments and Contingencies - Weighted Average Remaining Lease Term and Weighted Average Discount Rate to Determine the Operating Lease Liability (Details)	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term (years)	3 years 8 months 12 days
Weighted average discount rate	8.10%

Common Stock - Schedule of Rese

Common Stock - Schedule of Reserved Shares of Common Stock for Future Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	11,417,782	9,440,355
Shares Issuable Upon the Exercise of Outstanding Common Stock Options and the Vesting of Outstanding Common Restricted Stock Units Granted
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	7,130,956	4,269,861
Shares Available for Future Grant under 2020 Equity Incentive Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	3,158,094	4,253,854
Shares Available for Future Grant under Employee Stock Purchase Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	1,128,732	916,640

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2023	Jan. 01, 2024	Jan. 01, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	11,417,782			9,440,355
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Share based compensation maximum annual increase in number of shares that may be issued under the plan	3,230,000
Share based compensation percentage of number shares of common stock issued and outstanding on immediate proceeding	5%
Reserved shares of common stock for future issuance			1,893,869
2020 Equity Incentive Plan | Subsequent Event
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		1,908,630
2020 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Share based compensation maximum annual increase in number of shares that may be issued under the plan	646,000
Share based compensation percentage of number shares of common stock issued and outstanding on immediate proceeding	1%
Reserved shares of common stock for future issuance			378,774
2020 Employee Stock Purchase Plan | Subsequent Event
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		381,726

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 10,623	$ 10,606
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,003	3,217
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,620	$ 7,389

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield		0%
Fair value of options granted		$ 9,800	$ 16,300
Fair value of restricted stock units granted		500	100
Fair value of options vested		9,800	6,800
Aggregate intrinsic value of options exercised		200	3,000
Unrecognized compensation cost		$ 16,000
Remaining weighted-average period expected to recognize unrecognized compensation cost		1 year 11 months 26 days
Stock-based compensation expense		$ 10,623	10,606
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issued common stock, share under employee stock purchase plan		166,682
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Terms of award		Under the ESPP, eligible employees can authorize payroll deductions for amounts up to the lesser of 15% of their qualifying wages or the statutory limit under the U.S. Internal Revenue Code. The ESPP provides for offering periods of six months in duration with one purchase period per offering period beginning May 18 and November 18 of each year.
Offering periods	6 months
Percentage of fair market value of common shares	85%
Stock-based compensation expense		$ 100	$ 200
Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum percentage of payroll deductions for qualifying wages or statutory limit	15%
Shares of common stock purchased by each participant		10,000

Stock-based Compensation - Weig

Stock-based Compensation - Weighted-Average Assumptions used in Estimating Fair Value of each Stock Options using Black-Scholes Option-Pricing Model (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	3.54%	2.15%
Expected volatility	99.18%	92.95%
Expected term (in years)	5 years 10 months 2 days	6 years 7 days
Expected dividend yield	0%

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Option Activity Changes in Shares Available for Grant under the 2020 Plan (Details)	12 Months Ended
	Dec. 31, 2023 shares
Share-Based Payment Arrangement [Abstract]
Shares Available for Grant, Beginning Balance	4,253,854
2020 Plan reserve increase on January 1, 2023	1,893,869
Options and restricted stock units granted	(3,834,783)
Options and restricted stock units forfeited, cancelled, or expired	845,154
Shares Available for Grant, Ending Balance	3,158,094

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Shares, Beginning Balance	4,033,522
Shares, Granted	3,696,783
Shares, Exercised	(128,534)
Shares, Forfeited/expired	(780,902)
Shares, Ending Balance	6,820,869	4,033,522
Shares, Expected to vest	4,000,554
Shares, Options exercisable	2,820,315
Weighted-Average Exercise price per Share, Beginning Balance	$ 11.75
Weighted-Average Exercise price per Share, Granted	3.34
Weighted-Average Exercise price per Share, Exercised	1.29
Weighted-Average Exercise price per Share, Forfeited/expired	6.72
Weighted-Average Exercise price per Share, Ending Balance	7.97	$ 11.75
Weighted-Average Exercise price per Share, Expected to vest	6.41
Weighted-Average Exercise price per Share, Options exercisable	$ 10.18
Weighted-Average Remaining Contractual Term (in years)	8 years 2 months 26 days	8 years 4 months 24 days
Weighted-Average Remaining Contractual Term, Expected to vest (in years)	8 years 8 months 19 days
Weighted-Average Remaining Contractual Term, Options exercisable (in years)	7 years 6 months 21 days
Aggregate Intrinsic Value, Outstanding Balance	$ 387	$ 827
Aggregate Intrinsic Value, Options exercisable	$ 387

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	6,820,869	4,033,522
Shares Exercisable	2,820,315
Exercise Price $0.16 to 4.22
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	3,709,593
Shares Exercisable	1,005,785
Exercise Price $0.16 to 4.22 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 0.16
Exercise Price $0.16 to 4.22 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 4.22
Exercise Price $8.93 to 19.94
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	2,759,028
Shares Exercisable	1,615,758
Exercise Price $8.93 to 19.94 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 8.93
Exercise Price $8.93 to 19.94 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 19.94
Exercise Price $20.55 to 29.41
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	352,248
Shares Exercisable	198,772
Exercise Price $20.55 to 29.41 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 20.55
Exercise Price $20.55 to 29.41 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 29.41

Stock-based Compensation - Su_4

Stock-based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Equivalent, Non-vested, Beginning Balance | shares	236,339
Share Equivalent, Granted | shares	138,000
Share Equivalent, Cancelled | shares	(64,252)
Share Equivalent, Non-vested, Ending Balance | shares	310,087
Weighted-Average Grant Date Fair Value, Non-vested, Beginning Balance | $ / shares	$ 15.16
Weighted-Average Grant Date Fair Value, Non-vested, Granted | $ / shares	3.28
Weighted-Average Grant Date Fair Value, Non-vested, Cancelled | $ / shares	7.63
Weighted-Average Grant Date Fair Value, Non-vested, Ending Balance | $ / shares	$ 11.44

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
United States	$ (117,440)	$ (95,778)
Foreign	(232)	139
Net loss	$ (117,672)	$ (95,639)

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21%	21%
State Taxes		(0.40%)
Stock-based compensation	(1.10%)	(1.30%)
Non-deductible expenses and others	(0.10%)	(0.10%)
Tax credits	4.20%	2.20%
Change in valuation allowance	(24.00%)	(21.40%)
Effective income tax rate	0%	0%

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 31,342	$ 24,092
Research and development tax credit carryforwards	9,327	4,218
Accrued liabilities	2,828	2,781
Stock-based compensation	2,564	1,676
Operating lease liability	333	404
Other	180	121
Capitalized research and development	25,182	10,729
Total deferred tax assets	71,756	44,021
Deferred tax liabilities:
Right of use asset	(221)	(267)
Prepaid expenses and other	(75)	(475)
Investments	(214)	(294)
Total deferred tax liabilities	(510)	(1,036)
Less valuation allowance	(71,246)	(42,985)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Change in valuation allowance	$ 28,300,000	$ 20,400,000
Net operating loss carryforwards	138,700,000
Material interest and penalties on uncertain tax benefits	0
Deferred Tax Assets	25,200,000
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	9,500,000
Tax credit carryforwards	12,400,000
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 3,300,000
Minimum | Federal
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	8 years
Minimum | State
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration period	18 years
Maximum | Federal
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	14 years
Maximum | State
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration period	20 years

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits for Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Beginning balance	$ 1,406	$ 722
Additions for tax positions taken in prior year	182
Additions for tax positions taken in the current year	1,521	684
Ending balance	$ 3,109	$ 1,406

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Benefit Plans [Abstract]
Percentage of pretax compensation eligible to defer	100%
Matching contributions	$ 0.5	$ 0.4

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Summary of Dilutive Securities excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	7,134,451	4,275,009
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	6,820,869	4,033,522
Non-vested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	310,087	236,339
Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	3,495	5,148