Icosavax (ICVX) 10-K 30 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 21, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Entity Registrant Name	ICOSAVAX, INC.
Entity Central Index Key	0001786255
Entity File Number	001-40655
Entity Tax Identification Number	82-3640549
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Address Address Line1	1930 Boren Avenue, Suite 1000
Entity Address City Or Town	Seattle
Entity Address, State and Province	WA
Entity Incorporation State Country Code	DE
Entity Address Postal Zip Code	98101
Local Phone Number	737-0085
City Area Code	206
Security12b Title	Common Stock, $0.0001 par value per share
Trading Symbol	ICVX
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		41,395,981
Entity Public Float			$ 184
Auditor Name	Ernst & Young LLP
Auditor Location	Seattle, Washington
Auditor Firm ID	42
Documents Incorporated by Reference	Certain sections of the registrant’s definitive proxy statement for the 2023 annual meeting of stockholders to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Form 10-K are incorporated by reference into Part III of this Form 10-K.

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash	$ 58,846	$ 279,082
Restricted cash	1,061	1,642
Short-term investments	159,461	0
Prepaid expenses and other current assets	4,545	5,829
Total current assets	223,913	286,553
Property and equipment, net	11,517	1,076
Right-of-use assets operating leases	3,247	0
Total assets	238,677	287,629
Current liabilities:
Accounts payable	2,892	3,899
Accrued and other current liabilities	8,759	4,757
Current portion of operating lease liabilities	2,137	0
Deferred revenue	0	582
Total current liabilities	13,788	9,238
Operating lease liabilities, net of current portion	6,658	0
Other noncurrent liabilities	69	171
Total liabilities	20,515	9,409
Commitments and contingencies (Note 2)
Stockholders' equity (deficit):
Common stock, $0.0001 par value; 500,000,000 authorized at December 31, 2022 and 2021; 41,177,706 and 39,429,103 shares issued as of December 31, 2022 and 2021, respectively; 41,095,564 and 39,175,279 shares outstanding as of December 31, 2022 and December 31, 2021, respectively	6	5
Additional paid-in capital	404,386	372,284
Accumulated other comprehensive loss	(403)	0
Accumulated deficit	(185,827)	(94,069)
Total stockholders' equity (deficit)	218,162	278,220
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	$ 238,677	$ 287,629

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021	Aug. 02, 2021	Dec. 31, 2020
Preferred stock, shares authorized			50,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000	500,000,000
Common stock, shares issued	41,177,706	39,429,103
Common Stock Shares Outstanding	41,095,564	39,175,279
Convertible Preferred Stock [Member]
Convertible preferred stock, shares outstanding	0	0		32,198,879

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Grant revenue	$ 582	$ 7,802
Research and development	65,410	38,776
General and administrative	30,230	34,887
Total operating expenses	95,640	73,663
Loss from operations	(95,058)	(65,861)
Change in fair value of embedded derivative liability	0	(205)
Loss on extinguishment of convertible promissory note	0	(754)
Interest and other	3,300	(151)
Total other expense	3,300	(1,110)
Net loss	(91,758)	(66,971)
Other comprehensive loss:
Unrealized losses on available-for-sale debt securities	(403)
Comprehensive loss	$ (92,161)	$ (66,971)
Net loss per share, basic	$ (2.31)	$ (3.73)
Net loss per share, diluted	$ (2.31)	$ (3.73)
Weighted-average common shares outstanding, basic and diluted	39,725,131	17,965,894
Weighted-average common shares outstanding, basic and diluted	39,725,131	17,965,894

Statements of Convertible Prefe

Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Convertible Preferred Stock [Member]	Convertible Preferred Stock [Member] Series A-1 Convertible Preferred Stock [Member]	Convertible Preferred Stock [Member] Series B-1 Convertible Preferred Stock [Member]
Convertible preferred stock, Beginning Balance (in shares) at Dec. 31, 2020						32,198,879
Convertible preferred stock, Beginning Balance at Dec. 31, 2020						$ 30,062
Beginning Balance (in shares) at Dec. 31, 2020		2,639,026
Beginning Balance at Dec. 31, 2020	$ (26,703)	$ 2	$ 393	$ 0	$ (27,098)
Shares released from restriction upon vesting of early-exercised stock options (in shares)		344,179
Shares released from restriction upon vesting of early-exercised stock options	203		203
Vesting of shares of restricted common stock		469,493
Issuance of Series convertible preferred stock, (in shares)							21,944,874	32,958,612
Issuance of Series convertible preferred stock							$ 21,004	$ 92,630
Issuance of Series B-2 convertible preferred stock from convertible note (in shares)						2,805,850
Issuance of Series B-2 convertible preferred stock from convertible note						$ 7,917
Initial public offering, net of issuance costs, (in shares)		13,953,332
Initial public offering, net of issuance costs	190,737	$ 1	190,736
Conversion of convertible preferred stock into common stock, (in shares)		21,634,898				(89,908,215)
Conversion of convertible preferred stock into common stock	151,613	$ 2	151,611			$ (151,613)
Issuance of common stock for Employee Stock Purchase Plan, (in shares)		16,606
Issuance of common stock for Employee Stock Purchase Plan	212		212
Exercise of common stock options, (in shares)		117,745
Exercise of common stock options	98		98
Stock-based compensation	29,031		29,031
Net loss and comprehensive loss	(66,971)				(66,971)
Convertible preferred stock, Ending Balance (in shares) at Dec. 31, 2021						0
Convertible preferred stock, Ending Balance at Dec. 31, 2021						$ 0
Ending Balance (in shares) at Dec. 31, 2021		39,175,279
Ending Balance at Dec. 31, 2021	278,220	$ 5	372,284	0	(94,069)
Shares released from restriction upon vesting of early-exercised stock options (in shares)		171,682
Shares released from restriction upon vesting of early-exercised stock options	102		102
Vesting of shares of restricted common stock		302,281
Issuance of common stock for Employee Stock Purchase Plan, (in shares)		71,272
Issuance of common stock for Employee Stock Purchase Plan	$ 309		309
Exercise of common stock options, (in shares)	395,050	395,050
Exercise of common stock options	$ 585		585
Issuance of common stock, (in shares)		980,000
Issuance of common stock	9,413	$ 1	9,412
Stock-based compensation	21,694		21,694
Other comprehensive loss	(403)			(403)
Net loss and comprehensive loss	(91,758)				(91,758)
Convertible preferred stock, Ending Balance (in shares) at Dec. 31, 2022						0
Convertible preferred stock, Ending Balance at Dec. 31, 2022						$ 0
Ending Balance (in shares) at Dec. 31, 2022		41,095,564
Ending Balance at Dec. 31, 2022	$ 218,162	$ 6	$ 404,386	$ (403)	$ (185,827)

Statements of Convertible Pre_2

Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares
IPO [Member]
Payments of Stock Issuance Costs	$ 18.6
Series A-1 Convertible Preferred Stock [Member]
Issuance of convertible preferred stock per share | $ / shares	$ 0.9615
Convertible Preferred Stock Issuance Cost	$ 0.1
Series B-1 Convertible Preferred Stock [Member]
Issuance of convertible preferred stock per share | $ / shares	$ 2.82172
Convertible Preferred Stock Issuance Cost	$ 0.3

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss and comprehensive loss	$ (91,758)	$ (66,971)
Adjustments to reconcile net loss to cash used in operating activities:
Stock-based compensation	21,694	29,031
Depreciation	860	82
Non-cash lease expense	983	0
Amortization of premiums and discounts on short-term investments	(1,528)	0
Non-cash interest expense	0	264
Change in fair value of embedded derivative liability	0	205
Loss on extinguishment of convertible promissory note	0	(754)
Changes in operating assets and liabilities:
Prepaids and other current assets	1,284	(5,167)
Accounts payable	(1,195)	1,839
Accrued and other current liabilities	4,002	3,225
Deferred revenue	(582)	(1,802)
Proceeds from lease incentive	4,565	0
Net cash used in operating activities	(61,675)	(38,540)
Investing activities:
Purchases of property and equipment	(11,113)	(1,006)
Purchases of short-term investments	(221,086)	0
Maturities of short-term investments	62,750	0
Net cash used in investing activities	(169,449)	(1,006)
Financing activities:
Proceeds from issuance of convertible preferred stock, net of issuance costs	0	113,634
Proceeds from initial public offering, net of offering costs	0	190,738
Proceeds from issuance of common stock, net of issuance costs	9,413	0
Proceeds from exercise of stock options, including early exercise	894	400
Net cash provided by financing activities	10,307	304,772
Net increase (decrease) in cash, cash equivalents, and restricted cash	(220,817)	265,226
Cash, cash equivalents, and restricted cash at beginning of period	280,724	15,498
Cash, cash equivalents, and restricted cash at end of period	59,907	280,724
Supplemental disclosure of noncash activities
Conversion of preferred stock to common stock	0	151,613
Purchases of property and equipment included in accounts payable	330	142
Right-of-use assets and lease liabilities recognized upon commencement of lease	$ 3,370	$ 0

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business Organization Icosavax, Inc. (the “Company”) was incorporated in the state of Delaware on November 1, 2017, and is located in Seattle, Washington. The Company is focused on the research and development of vaccines against infectious diseases. The Company was founded on computationally designed virus-like particle technology, exclusively licensed for a variety of infectious disease indications from the Institute for Protein Design at the University of Washington. The Company’s business involves inherent risks. These risks include, among others, dependence on key personnel, licensors and third-party service providers, patentability of the Company’s products and processes, the immunogenicity, efficacy and safety of the Company’s vaccine candidates and the potential of the Company's novel vaccine technology platform. In addition, any of the Company’s vaccine candidates, and the Company's vaccine technology platform, could become obsolete or diminished in value by discoveries and developments at other organizations. In July 2021, the Company effected a 1-for-4.1557 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s convertible preferred stock. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustment of the convertible preferred stock conversion ratios. On August 2, 2021, the Company completed its initial public offering (“IPO”) pursuant through which it issued 12,133,333 shares of its common stock at a public offering price of $ 15.00 per share, and on August 2, 2021, the Company sold an additional 1,819,999 shares pursuant to the exercise by the underwriters of their option to purchase additional shares. The Company received net proceeds from its IPO, inclusive of the exercise by the underwriters of their option to purchase additional shares, of $ 190.7 million, after deducting underwriting discounts and commissions and offering expenses. Upon the closing of the IPO, all 89,908,215 shares of the then outstanding convertible preferred stock automatically converted into 21,634,898 shares of common stock. Liquidity The Company had an accumulated deficit of $ 185.8 million, cash, cash equivalents, and short-term investments of $ 218.3 million, and restricted cash of $ 1.1 million at December 31, 2022. Management believes the Company has sufficient capital to execute its strategic plan and fund operations through at least the next twelve months from the date these financial statements are issued. The Company has devoted substantially all of its resources to organizing and staffing the Company, business planning, raising capital, in-licensing intellectual property rights, developing vaccine candidates, scaling up manufacturing of vaccine candidates, and preparing for and conducting preclinical studies and clinical trials. The Company has a limited operating history, and the sales and income potential of its business is unproven. The Company has incurred net losses and negative cash flows from operating activities since its inception and expects to continue to incur net losses into the foreseeable future as it continues the development of its vaccine candidates. From inception to December 31, 2022, the Company has funded its operations primarily through the sale of its convertible preferred stock and common stock. As the Company continues to pursue its business plan, it expects to finance its operations through equity offerings, debt financings or other capital sources, including potential strategic collaborations, licenses, and other similar arrangements. However, there can be no assurance that any additional financing or strategic transactions will be available to the Company on acceptable terms, if at all. If events or circumstances occur such that the Company does not obtain additional funding, it may need to delay, reduce or eliminate its product development or future commercialization efforts, which could have a material adverse effect on the Company’s business, results of operations or financial condition. The accompanying financial statements do not include any adjustments that might be necessary if the Company were unable to continue as a going concern.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported balances of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates are used for, but not limited to, stock-based compensation, derivative liability, the timing of research and development accruals, and income taxes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions. Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents, restricted cash, and short-term investments. 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 maintains insured cash sweep accounts where balances are maintained in interest bearing demand accounts. The Company has not realized any losses on these deposits, and management believes that the Company is not exposed to significant credit risk due to the financial positions of the respective depository institutions in which those deposits are held, and its short-term investments are in high credit quality securities including U.S. Treasury and U.S. Agency securities, commercial paper, and highly rated corporate debt securities . Cash and Cash Equivalents and Restricted Cash Cash and cash equivalents consists of deposits with commercial banks in checking and interest-bearing accounts, highly rated money market funds, and all highly liquid investments with an original maturity of 90 days or less at the time of purchase. At December 31, 2022 and 2021, restricted cash includes cash deposited in a collateral account to support a letter of credit issued as security for the Company's operating lease to rent office and laboratory space in Seattle, Washington. At December 31, 2021, restricted cash also includes payments received under the Grant Agreement (as defined in Note 4) with the Bill & Melinda Gates Foundation (“BMGF”). Investments Investments include U.S. Treasury and U.S. Agency securities, commercial paper, and corporate debt securities with a final maturity of each security of less than one year. These investments are classified as available-for-sale debt securities, which are recorded at fair value based on quoted prices in active markets. The Company classifies investments maturing within one year of the reporting date as short-term investments. The Company periodically evaluates whether declines in the fair values of its investments below their amortized cost basis are other-than-temporary. This evaluation considers qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs, including whether the Company has plans to sell the security or whether it is more likely than not the Company will be required to sell any investment before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the investments, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the investment. If the estimated fair value of a debt security is below its amortized cost basis, the Company evaluates whether credit losses exist for the related securities. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment recognized in net loss. Unrealized gains and losses that are unrelated to credit deterioration are reported in other comprehensive loss. The Company recognizes purchase premiums and discounts as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other-than-temporary are reflected in the statements of operations and comprehensive loss using the specific-identification method. Fair Value of Financial Instruments The accounting guidance defines fair value, establishes a consistent framework for measuring fair value, and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of prepaid expenses and other assets, accounts payable, and accrued and other current liabilities are considered to be representative of their respective fair values due to their short maturities. Property and equipment, net Property and equipment, net is stated at cost, net of accumulated depreciation and is depreciated using the straight-line method over the estimated useful lives of the assets, generally two to five years, while leasehold improvements are depreciated over the shorter of their estimated useful lives or the related lease term . Impairment of Long-Lived Assets The Company regularly reviews the carrying value and estimated lives of its long-lived assets, including property and equipment to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. Should an impairment exist, the impairment loss would be measured based on the excess over the carrying amount of the asset’s fair value. The Company has no t recognized any impairment losses from inception through December 31, 2022. Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible note (see Note 7) had conversion and redemption features that met the definition of an embedded derivative and were therefore subject to bifurcation and derivative accounting. The initial recognition of the fair value of the derivative resulted in a discount to the convertible note, with a corresponding derivative liability. The discount to the convertible note was amortized using the effective interest method. The amortization of the discount is included in interest and other expense in the statements of operations and comprehensive loss. The derivative liability related to these features was recorded at estimated fair value and remeasured on a recurring basis. Any changes in fair value were reflected as change in fair value of derivative liability in the statements of operations and comprehensive loss at each reporting date while such instruments were outstanding. The derivative liability was settled in March 2021 upon conversion of the underlying convertible note into Series B convertible preferred stock, resulting in a loss on extinguishment of convertible promissory note . Leases At the inception of a contractual arrangement, the Company determines whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. If both criteria are met, the Company records the associated lease liability and corresponding right-of-use ("ROU") asset upon commencement of the lease using the implicit rate or a discount rate based on a credit-adjusted secured borrowing rate commensurate with the term of the lease. The Company additionally evaluates leases at their inception to determine if they are to be accounted for as an operating lease or a finance lease. A lease is accounted for as a finance lease if it meets one of the following five criteria: the lease has a purchase option that is reasonably certain of being exercised, the present value of the future cash flows is substantially all of the fair market value of the underlying asset, the lease term is for a significant portion of the remaining economic life of the underlying asset, the title to the underlying asset transfers at the end of the lease term, or if the underlying asset is of such a specialized nature that it is expected to have no alternative uses to the lessor at the end of the term. Leases that do not meet the finance lease criteria are accounted for as an operating lease. Operating lease assets represent a right to use an underlying asset for the lease term and operating lease liabilities represent an obligation to make lease payments arising from the lease. Operating lease liabilities with a term greater than one year and their corresponding ROU assets are recognized on the balance sheet at the commencement date of the lease based on the present value of lease payments over the expected lease term. Certain adjustments to the ROU asset may be required for items such as initial direct costs paid or incentives received. As the Company’s leases do not typically provide an implicit rate, the Company utilizes the appropriate incremental borrowing rate, determined as the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term and in a similar economic environment. Lease cost is recognized on a straight-line basis over the lease term and variable lease payments are recognized as operating expenses in the period in which the obligation for those payments is incurred. Variable lease payments primarily include common area maintenance, utilities, real estate taxes, insurance, and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company has elected the practical expedient to not separate lease and non-lease components . Liability for Early Exercise of Stock Options Certain individuals were granted the ability to early exercise their stock options. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest in accordance with the original vesting schedule. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options on the accompanying balance sheets and will be reclassified as common stock and additional paid-in capital as the shares vest. Unvested shares issued under early exercise provisions subject to repurchase by the Company totaled 82,142 and 253,824 shares as of December 31, 2022 and 2021, respectively. As of December 31, 2022 and 2021, the Company recorded $ 0.1 million and $ 0.2 million respectively, related to shares issued with repurchase rights as other noncurrent liabilities in the accompanying balance sheets. Commitments and Contingencies The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has been incurred, and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount the Company accrues the minimum amount in the range. In the event the Company becomes subject to claims or suits arising in the ordinary course of business, the Company would accrue a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. The Company has not recorded any such liabilities at either December 31, 2022 or 2021. Grant Revenue The Company’s revenue consists of revenue under its prior Grant Agreement with BMGF (see Note 4). The Company was reimbursed for certain costs that support development activities, including the Company’s clinical trial notification (“CTN”) preparations for and planned first-in-human Phase 1/2 clinical trial of the Company's former IVX-411 SARS-CoV-2 vaccine in Australia. The Company’s Grant Agreement did not provide a direct economic benefit to BMGF. Rather, the Company entered into an agreement with BMGF to make a certain amount of any resulting vaccine available and accessible at affordable pricing to people in certain low- and middle-income countries. The Company assessed this cost reimbursement agreement to determine if the agreement should be accounted for as an exchange transaction or a contribution. Such an agreement is accounted for as a contribution if the resource provider does not receive commensurate value in return for the assets transferred. Contributions are recognized as grant revenue when all donor-imposed conditions have been met. Accrued Research and Development Expense The Company is required to estimate its obligation for expenses incurred under contracts with vendors, consultants, and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its financial statements by recognizing those expenses in the periods in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical study or clinical trial, as measured by the timing of various aspects of the study, trial or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel and third-party service providers as to the progress of studies or trials, or other services being conducted. To date, the Company has had no material differences between its estimates of such expenses and the amounts actually incurred. During the course of a study or trial, the Company adjusts its expense recognition if actual results differ from its estimate. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed. Research and Development Research and development costs are expensed as incurred and consist primarily of external and internal costs related to the development of vaccine candidates, including salaries and benefits, stock-based compensation, facilities and depreciation, contracted research, consulting arrangements, and other expenses incurred to sustain the Company’s research and development programs . Interest Income Interest income consists of interest income earned on short-term investments in debt securities and interest bearing demand accounts. Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee, officer, director and non-employee stock option grants, estimated in accordance with the applicable accounting guidance, recognized on a straight-line basis over the vesting period. The vesting period generally approximates the expected service period of the awards. The Company recognizes forfeitures as they occur. The fair value of restricted stock units (“RSUs”) is based on the closing price of the Company's common stock on the grant date. The fair value of stock options is estimated using the Black-Scholes option pricing model. The Black-Scholes option pricing model uses inputs which are assumptions that generally require judgment. These assumptions include: ▪ Fair Value of Common Stock . The grant date fair value of the Company’s common stock is determined based on its closing price. ▪ Expected Term . The expected term represents the period that the options granted are expected to be outstanding. The expected term of stock options issued is determined using the simplified method (based on the average of the vesting term and the original contractual term) as the Company has concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term. ▪ Expected Volatility . Given the Company’s limited historical stock price volatility data, the Company derived the expected volatility from the average historical volatilities over a period approximately equal to the expected term of comparable publicly traded companies within the Company’s peer group that were deemed to be representative of future stock price trends as the Company has limited trading history for its common stock. 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. ▪ 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 options. ▪ Expected Dividend Yield . The Company has never paid dividends on its common stock and does not anticipate paying any dividends in the foreseeable future. Therefore, the Company used an expected dividend yield of zero. Significant changes to the key assumptions underlying the factors used could result in different fair values of stock options at each valuation date. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. As of December 31, 2022 and 2021, the Company maintained valuation allowances against its deferred tax assets as the Company concluded it had not met the “more likely than not” to be realized threshold. Changes in the valuation allowance when they are recognized in the provision for income taxes may result in a change in the estimated annual effective tax rate. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. As of December 31, 2022, the Company had no accrued interest or penalties. Comprehensive Loss Comprehensive loss comprises net loss and certain changes in equity excluded from net loss. For the year ended December 31, 2022, other comprehensive loss included unrealized losses on the Company's short-term investments in available-for-sale debt securities. The Company’s comprehensive loss was the same as its reported net loss for the year ended December 31, 2021. Net Loss Per Share Basic net loss per share 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. Diluted net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock and common stock equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding stock options and restricted stock units under the Company’s equity incentive plan and have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. The following tables summarize the computation of the basic and diluted net loss per share (in thousands, except share and per share data): Year Ended 2022 2021 Numerator: Net loss $ ( 91,758 ) $ ( 66,971 ) Denominator: Weighted-average common shares outstanding, basic and diluted 39,725,131 17,965,894 Net loss per share, basic and diluted $ ( 2.31 ) $ ( 3.73 ) The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. Year Ended 2022 2021 Common stock options and restricted stock units 9,387,963 6,591,727 ESPP shares 66,488 16,606 Unvested common stock 82,142 253,824 Total 9,536,593 6,862,157 Segments The Company has determined that it operates and manages one operating segment, which is the business of researching and developing vaccines against infectious diseases. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources. All assets of the Company are located in the United States. Recent Accounting Pronouncements Recently Adopted Accounting Standards In December 2019, the FASB issued ASU 2019-12, Income Taxes—Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance to reduce complexity in certain areas, such as requiring that an entity reflect the effect of an enacted change in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. The new standard is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022 for all non-public entities, with early adoption permitted, and is effective for fiscal years beginning after December 15, 2020, including interim periods within those annual periods for public entities. Early adoption is permitted. The Company adopted ASU 2019-12 on January 1, 2021 and the standard did not have a material impact on its financial statements and related disclosures. Recently Issued Accounting Standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02 ("ASU 2016-13"). 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. ASU 2016-13 will become effective beginning January 1, 2023, with early adoption permitted. The adoption of ASU 2016-13 did not have a material impact on the Company's financial condition, results of operations, cash flows, and financial statement disclosures.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Disclosures	3. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: 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 for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 —Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e. supported by little or no market activity). No transfers between levels have occurred during the periods presented. The Company measures the fair value of money market funds and U.S. Treasury securities based on quoted prices in active markets for identical securities. The Company measures the fair value of U.S. Agency securities, corporate debt securities and commercial paper based on recent trades of securities in inactive markets or based on quoted prices of similar instruments in active markets and other significant inputs derived from or corroborated by observable market data. The following table summarizes, by major security type, the Company's cash, cash equivalents, and investments that are measured at fair value on a recurring basis by level within the fair value hierarchy as of December 31, 2022 (in thousands): December 31, 2022 Fair Value Hierarchy Level Amortized Cost Gross Unrealized Gross Unrealized Fair Market Value Assets: Cash and cash equivalents: Cash Level 1 $ 23,376 $ — $ — $ 23,376 Money market funds Level 1 35,470 — — 35,470 Total cash and cash equivalents 58,846 — — 58,846 Investments: U.S. Treasury securities Level 1 82,277 3 ( 331 ) 81,949 U.S. Agency securities Level 2 14,044 28 — 14,072 Corporate debt securities and commercial paper Level 2 63,543 — ( 103 ) 63,440 Total investments 159,864 31 ( 434 ) 159,461 Total assets measured at fair value on a recurring basis $ 218,710 $ 31 $ ( 434 ) $ 218,307 As of December 31, 2021, the Company considered the carrying amounts of cash and cash equivalents to be representative of their respective fair values due to their short maturities. All investments held as of December 31, 2022 were classified as available-for-sale debt securities and had contractual maturities within one year. There were no realized gains or losses on these securities for the year ended December 31, 2022. The aggregate fair value of available-for-sale debt securities in an unrealized loss position as of December 31, 2022 was $ 90.3 million. The Company evaluated its investments for other-than-temporary impairment and considered the decline in market value for the securities to be temporary in nature. It is not more likely than not that the Company will be required to sell the investments, and the Company does not intend to do so prior to recovery of the amortized cost basis. As further described in Note 7, the Company issued a convertible promissory note in August 2020. The convertible promissory note contained certain features that met the definition of a derivative and were required to be bifurcated. The Company accounted for these as a single derivative comprising all the features requiring bifurcation. The fair value of the derivative liability was estimated using a scenario-based analysis comparing the probability-weighted present value of the convertible promissory note payoff at maturity with and without the bifurcated features. The Company considered possible outcomes available to the noteholders, including various financing dissolution scenarios. In addition, the probabilities applied to various scenarios, the key unobservable inputs are the time to liquidity for each scenario, and the discount rate. The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the derivative liability: March 19, 2021 Probability of financing 100 % Probability of dissolution — Time to liquidity (years) — Discount rate 7.6 % The Company adjusted the carrying value of the derivative liability within the convertible promissory note to the estimated fair value at each reporting date, with any related increases or decreases in the fair value recorded as change in fair value of derivative liability in the statements of operations and comprehensive loss. For the year ended December 31, 2021, the Company recognized $ 0.2 million of other income in the statements of operations and comprehensive loss related to increases in the fair value of the embedded derivative liability. On March 19, 2021, in connection with the closing of the Series B convertible preferred stock financing, the convertible promissory note (including accrued interest) and derivative liability converted into 2,805,850 shares of Series B-2 convertible preferred stock. As a result of the conversion, the Company recorded a loss on extinguishment of convertible promissory note of $ 0.8 million of other expense in the statements of operations and comprehensive loss for the year ended December 31, 2021, which included the derecognition of unamortized debt issuance costs. The following table provides a reconciliation of the fair value of the derivative liability using Level 3 significant unobservable inputs (in thousands): Derivative Liability Fair value at December 31, 2020 $ ( 1,604 ) Change in fair value of embedded derivative liability ( 205 ) Reclassification of derivative liability into convertible preferred stock resulting from conversion of convertible promissory note 1,809 Fair value at December 31, 2021 $ —

Grant Agreement

Grant Agreement	12 Months Ended
	Dec. 31, 2022
Grant Agreement [Abstract]
Grant Agreement	4. Grant Agreement Bill & Melinda Gates Foundation Grant Agreement In support of the Company’s development of its former IVX-411 COVID-19 vaccine for pandemic use, in September 2020, the Company entered into the grant agreement (the “Grant Agreement”) with the Bill & Melinda Gates Foundation (“BMGF”), under which it was awarded a grant totaling up to $ 10.0 million (the “Grant”). The Grant supported development activities related to IVX-411, including the Company’s regulatory filing preparations and its Phase 1/2 clinical trial of IVX-411. The Grant Agreement terminated in accordance with its terms on March 31, 2022. Concurrent with and in connection with the Grant Agreement, the Company entered into a Global Access Commitments Agreement (“GACA”) with BMGF. Under the terms of the GACA, among other things, the Company agreed to make a certain amount of its IVX-411 COVID-19 vaccine available and accessible at affordable pricing to people in certain low- and middle-income countries, if the vaccine was commercialized. The Company discontinued its IVX-411 program in July 2022. Payments received in advance that were related to future performance were deferred and recognized as revenue when the research and development activities were performed. Cash payments received under the Grant Agreement were restricted as to their use until eligible expenditures were incurred. At December 31, 2022, the Company had no restricted cash and no deferred revenue, and at December 31, 2021, had $ 0.6 million of restricted cash and deferred revenue, representing funds received from BMGF and the Company's estimate of costs to be reimbursed and revenue to be recognized, respectively, in the next twelve months under the Grant Agreement. The Company received no funding from BMGF during the year ended December 31, 2022. During the year ended December 31, 2021, the Company received $ 6.0 million in funding from BMGF. During the years ended December 31, 2022 and 2021, the Company recognized revenue from the Grant Agreement of $ 0.6 million and $ 7.8 million, respectively. The Company had received the full $ 10.0 million in funding under the Grant Agreement as of December 31, 2021, and through December 31, 2022, the Company has recognized $ 10.0 million in revenue since the inception of the Grant Agreement.

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	5. Balance Sheet Details Property and equipment, net, consists of the following (in thousands): As of December 31, 2022 2021 Laboratory equipment $ 2,192 $ 856 Leasehold improvements 9,660 — Office furniture and equipment 608 — Construction in progress — 303 Property and equipment, cost 12,460 1,159 Accumulated depreciation ( 943 ) ( 83 ) Property and equipment, net $ 11,517 $ 1,076 Depreciation expense was $ 0.9 million for the year ended December 31, 2022, and $ 0.1 million for the year ended December 31, 2021. Accrued and other current liabilities consist of the following (in thousands): As of December 31, 2022 2021 Taxes payable $ 80 $ — Accrued paid time off 664 342 Accrued bonus 3,135 2,216 Other accrued liabilities 4,512 1,977 Accrued 401k 324 156 ESPP liability 44 66 Total accrued and other current liabilities $ 8,759 $ 4,757

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2022
License Agreements [Abstract]
License Agreements	6. License Agreements License Agreement with the National Institutes of Health The Company is a party to a non-exclusive patent license agreement (as amended, the “NIH Agreement”) with a U.S. government entity, the National Institutes of Health, represented by National Institute of Allergy and Infectious Disease (“NIAID”), which was originally entered into in June 2018. Under the NIH Agreement, the Company obtained a non-exclusive, worldwide, royalty-bearing, sublicensable license under certain NIAID patent rights, and transfer of know-how and biological materials for use in adjuvanted or non-adjuvanted vaccines for the prevention, cure, or treatment of RSV and metapneumovirus (hMPV) infection in humans. Under the NIH Agreement, the Company is required to use commercially reasonable efforts to meet certain specified development, sales and regulatory milestones related to the licensed products within specified time periods. In consideration of the rights granted to the Company under the NIH Agreement, the Company paid a licensing fee upon execution of the NIH Agreement of $ 100,000 , and will pay annual minimum royalty payments starting in the second year after the initial sale of each licensed product which can be credited against any earned royalties due for sales made in the year. The Company is obligated to pay aggregate potential milestone payments of up to $ 8.6 million with respect to future development and commercial milestones. Additionally, the Company has agreed to pay a tiered royalty of a low single digit percentage on net sales of all products applicable to the license. Additional royalties would be due in connection with sublicenses. The Company’s royalty obligations continue for each licensed product for so long as licensed patent rights exist and have not expired, been revoked, lapsed, or held unenforceable. The NIH Agreement will terminate upon the last expiration of the patent rights or the Company may terminate the entirety of the agreement upon discontinuation of development or sales of licensed products and provision of written notice thereof to NIH. The Company incurred fees associated with the license, recorded as research and development expenses, of $ 0.1 million during the year ended December 31, 2022, and $ 0.2 million during the year ended December 31, 2021. License Agreements with University of Washington License Agreement with respect to RSV and Other Pathogens The Company is a party to an exclusive license agreement with the University of Washington (“UW”), originally entered into in June 2018 (as amended, the “UW 2018 Agreement”). Under the UW 2018 Agreement, UW granted the Company an exclusive, worldwide, royalty-bearing, sublicensable license under certain UW patents to make, use, sell, offer to sell, import, and otherwise exploit any product covered by the licensed patents, or licensed products, for the prophylactic and/or therapeutic treatment of RSV infection, hMPV infection and eight other infectious diseases. UW also granted the Company a non-exclusive, worldwide license under certain know-how related to the licensed patents. The licensed patents and know-how generally relate to computationally designed nanoparticles and vaccines based upon such designs, and relate to the Company’s proprietary two-component virus-like-particle technology as well as certain one-component virus-like-particle technology. The Company’s rights and obligations under the UW 2018 Agreement are subject to certain U.S. government rights, certain global access commitment rights for humanitarian purposes to BMGF, certain rights to Howard Hughes Medical Institute ("HHMI"), and certain other limited rights retained by UW. The Company issued 192,276 shares of common stock on August 1, 2018 in exchange for the UW 2018 Agreement’s exclusive license. Under the UW 2018 Agreement, the Company is required to use commercially reasonable efforts to meet certain specified development, regulatory and sales milestones related to the licensed products within specified time periods. In consideration of the rights granted to the Company under the UW 2018 Agreement, the Company is required to pay an annual maintenance fee in the mid four figures starting in 2020. Additionally, the Company is required to pay minimum annual royalties following the first year after commercial sale of each licensed product. There are milestone payments due upon the completion of certain development, regulatory, and commercial milestones for licensed products in the future. The aggregate potential milestone payments for future development, regulatory, and sales-based milestones are $ 1.35 million per indication, up to a maximum of $ 12.2 million in total milestone payments. Additionally, the Company has agreed to pay a royalty of a low single digit percentage on net sales of all licensed products. Additional royalties would be due in connection with sublicenses. The Company’s royalty obligations continue for each licensed product for so long as licensed patent rights exist and have not expired, been revoked, lapsed, or held unenforceable. Unless terminated earlier, the UW 2018 Agreement will remain in effect until all licensed patent rights have terminated and all obligations due to UW have been fulfilled. The last-to-expire licensed patent, if issued, is expected to expire in 2042, subject to any adjustment or extension of patent term that may be available. UW can terminate the UW 2018 Agreement if the Company breaches or fails to perform one of its material duties under the UW 2018 Agreement and the Company is unable to remedy the default within an agreed upon time period that can be extended by UW. The Company may terminate the UW 2018 Agreement at will with prior written notice to UW. Option and License Agreement with Respect to COVID-19 The Company is also a party to an option and license agreement, originally entered into in July 2020 (as amended, the “UW 2020 Agreement”). Under the UW 2020 Agreement, UW granted the Company a non-exclusive, worldwide (excluding South Korea), sublicensable license under certain UW patents to make, use, sell, offer to sell, import, or otherwise exploit any product covered by the licensed patents for the prophylactic and/or therapeutic treatments of SARS-CoV-2 infection. Under an option exercised by the Company, UW granted the Company an exclusive license under the licensed patents for the United States, Canada, Mexico, and Europe (including Switzerland and the United Kingdom) starting in 2025. UW also granted the Company a non-exclusive, worldwide license under certain know-how related to the licensed patents. The licensed patents and know-how generally relate to computationally designed nanoparticles and vaccines based upon such designs. The Company’s rights and obligations under the UW 2020 Agreement are subject to certain U.S. government rights, certain global access commitment rights for humanitarian purposes to BMGF, certain rights to HHMI, and certain other limited rights retained by UW. Under the UW 2020 Agreement, the Company is required to use commercially reasonable efforts to meet certain specified development, regulatory and sales milestones related to the licensed products within specified time periods. The Company has agreed to pay a royalty of a low single digit percentage on net sales of all products applicable to the license. However, the Company will not be required to pay royalties on net sales of any licensed product under the UW 2020 Agreement if the Company is required to pay royalties on net sales under the UW 2018 Agreement. Additional royalties would be due in connection with sublicenses and milestones. The Company’s royalty obligations continue for each licensed product for so long as licensed patent rights exist and have not expired, been revoked, lapsed, or held unenforceable. Unless terminated earlier, the UW 2020 Agreement will remain in effect until all licensed patent rights have terminated and all obligations due to UW have been fulfilled. The last-to-expire licensed patent, if issued, is expected to expire in 2041, subject to any adjustment or extension of patent term that may be available. UW can terminate the UW 2020 Agreement if the Company breaches or fails to perform one of its material duties under the UW 2020 Agreement and the Company is unable to remedy the default within an agreed upon time period that can be extended by UW. The Company may terminate the UW 2020 Agreement at will with prior written notice to UW. During the year ended December 31, 2022, the Company incurred fees associated with the 2018 and 2020 Agreements, recorded as research and development expenses, of $ 0.5 million. During the year ended December 31, 2021, the Company incurred fees associated with the 2018 and 2020 Agreements of $ 0.2 million. License Agreement with Respect to Influenza The Company is a party to a license agreement with UW ("UW Flu License Agreement") entered into in September 2021. Pursuant to the UW Flu License Agreement, UW granted the Company a non-exclusive, worldwide, royalty-bearing, sublicensable (subject to certain restrictions) license under certain UW patents to make, use, sell, offer to sell, import, and otherwise exploit any product covered by the licensed patents ("Licensed Flu Products"), for the prophylactic and/or therapeutic treatment of influenza. UW also granted the Company a non-exclusive, worldwide license to use certain know-how related to the licensed patents. The licensed patents and know-how generally relate to computationally designed nanoparticles and vaccines based upon such designs, and relate to the Company's proprietary two-component virus-like-particle technology and nanoparticle-based influenza virus vaccines. The United States federal government and HHMI have similar rights under the UW Flu License Agreement and the UW 2018 Agreement described above in “License Agreement with respect to RSV and Other Pathogens". The Company is obligated to use commercially reasonable efforts to commercialize Licensed Flu Products, and to initiate a clinical trial with respect to such Licensed Flu Products by a specified date in 2025. If the Company is unable to initiate a clinical trial by the specified date and cannot agree with UW to modify such obligation or does not cure by meeting such obligation, then UW may terminate the UW Flu License Agreement. Under the UW Flu License Agreement, the Company paid UW a one-time upfront license fee, and after September 2023 and for the remainder of the term of the UW Flu License Agreement, the Company is required to pay tiered minimum annual fees ranging from the mid four figures to the mid five figures, with such fees creditable against royalty payments. The Company is required to pay UW up to an aggregate of $ 6.4 million for payments related to development and commercial milestones. The Company is also required to pay UW a fixed, low single-digit percentage royalty on net sales of Licensed Flu Products by the Company and its sublicensees, subject to certain reductions if the Company is required to pay for third-party intellectual property rights in order to commercialize the Licensed Flu Products. The Company is not obligated to pay duplicate royalties on net sales of any Licensed Flu Products if the Company is already required to pay a royalty on such net sales under the UW 2018 Agreement and the UW 2020 Agreement. Unless terminated earlier, the UW Flu License Agreement will remain in effect until all licensed patent rights have expired and all obligations due to UW have been fulfilled. The last-to-expire licensed patent, if issued, is expected to expire in 2041 , subject to any adjustment or extension of patent term that may be available. UW can terminate the UW Flu License Agreement if the Company breaches or fails to perform one of its material duties under the UW Flu License Agreement and is unable to remedy the default within an agreed upon time period that can be extended by UW. The Company can terminate the UW Flu License Agreement at will with prior written notice to UW. During the year ended December 31, 2022, the Company incurred fees associated with the UW Flu License Agreement, recorded as research and development expenses, of $ 0.2 million. During year ended December 31, 2021, the Company incurred fees associated with the UW Flu License Agreement of $ 0.1 million. License Agreement with the University of Texas The Company is a party to an exclusive patent license agreement with the University of Texas at Austin (“UT”) with respect to its hMPV antigen utilized in the IVX-A12 program (the “UT Agreement”). The UT Agreement was entered into in June 2021. Under the UT Agreement, UT granted the Company an exclusive, worldwide, royalty-bearing, sublicensable license under certain patent rights, to use licensed know-how for prevention, cure, amelioration or treatment of respiratory disease caused by hMPV infection in all vaccine fields, excluding up to one mRNA-based vaccine. The Company is obligated to pay aggregate potential milestone payments of up to $ 4.6 million with respect to future development and commercial milestones. Unless terminated earlier, the UT Agreement will remain in effect until all the licensed patent rights have expired. The Company may terminate the UT Agreement with prior written notice to UT. UT may terminate the UT Agreement in whole or in part, or narrow the vaccine field, reduce the territory, or convert the license from exclusive to non-exclusive if the Company: (i) fails to meet its payment obligations, (ii) commits an uncured breach, (iii) commits three or more cured breaches within a specified time period, (iv) challenges the validity, enforceability, or scope of the licensed patent rights, or (v) undergoes certain insolvency-related events. During the year ended December 31, 2022, the Company incurred fees associated with the UT Agreement of $ 0.1 million, recorded as research and development expenses. During year ended December 31, 2021, the Company incurred a negligible amount in fees associated with the UT Agreement.

Convertible Promissory Note

Convertible Promissory Note	12 Months Ended
	Dec. 31, 2022
Temporary Equity Disclosure [Abstract]
Convertible Promissory Note	7. Convertible Promissory Note In August 2020, the Company issued a $ 6.5 million convertible promissory note (“Convertible Promissory Note”). The Convertible Promissory Note accrued interest at a rate of 6 % a year with maturity date two years from issuance. The Convertible Promissory Note could be converted or redeemed as follows (i) automatically converted in a qualified Series B financing transaction from which the Company would receive total gross proceeds of not less than $ 5.0 million at a conversion price equal to 85 % of the per share price paid by investors for such securities, (ii) automatically converted upon initial public offering at a conversion price equal to 85 % of the per share price off common stock in the initial public offering, (iii) optionally converted into Series A-3 preferred stock if a change in control, initial public offering, or qualified Series B financing had not occurred prior to the maturity date at a price equal to an amount determined by dividing $ 140 million by the fully diluted capitalization of the Company at the time of conversion, or (iv) repaid upon a change in control for an amount equal to the issue price plus accrued and unpaid interest or an amount as would have been payable if the noteholders had optionally converted into shares of Series A-3 preferred stock. The Convertible Promissory Note was converted in March 2021 in connection with the Series B financing. The Convertible Promissory Note was accounted for in accordance with ASC 470-20, Debt with Conversion and Other Options (“ASC 470-20”) and ASC 815-15, Derivatives and Hedging - Embedded Derivatives (“ASC 815-15”). Under ASC 815-15, an embedded feature is required to be bifurcated if all three conditions are met: (1) economic characteristics and risks of the embedded derivative are not clearly and closely related to the economic characteristics and risks of the host contract, (2) the hybrid instrument is not remeasured at fair value under otherwise applicable GAAP with changes in fair value reported in earnings as they occur, and (3) a separate instrument which the same terms as the embedded derivative would be considered a derivative instrument subject to derivative accounting (the initial net investment for the hybrid instrument should not be considered to be the initial net investment for the embedded derivative. The Company bifurcated certain features that were required to be accounted separately for as a single embedded derivative. The initial fair value of this derivative of $ 1.8 million was recorded as a liability, and as a reduction to the carrying value of the Convertible Promissory Note. The Company also incurred a negligible amount of issuance costs related to the Convertible Promissory Note, which were also recorded as a reduction to the Convertible Promissory Note on the balance sheet. The debt discount comprised the initial fair value of the derivative liability and the issuance costs, and was amortized using the effective interest method over the two-year contractual term of the Convertible Promissory Note and presented as a direct reduction of the debt liability. The debt discount was being amortized at an effective interest rate of 23.8 %. Interest expense incurred in connection with the Convertible Promissory Note consisted of the following (in thousands): Year Ended December 31, 2021 Coupon interest at 6% $ 86 Accretion of discount and amortization of issuance costs 177 Total interest expense on Convertible Promissory Note $ 263 On March 19, 2021, in connection with the closing of the Series B convertible preferred stock financing, the Convertible Promissory Note (including accrued interest) and derivative liability converted into 2,805,850 shares of Series B-2 convertible preferred stock at an issuance price of $ 2.39846 per share. As a result of the conversion, the Company recorded a loss on extinguishment of convertible promissory notes of $ 0.8 million of other expense in the statements of operations and comprehensive loss for the year ended December 31, 2021, which included the unamortized debt issuance costs.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	8. Leases In January 2020, and amended in March 2020, the Company entered into a 12-month lease agreement with renewal options for office and laboratory space in Seattle, Washington. The lease was terminated in June 2022. The lease agreement was considered short-term and therefore, no right-of-use asset or lease liability was recorded. In December 2021, the Company entered into a lease agreement for corporate office and laboratory space in Seattle, Washington. The Company took possession of certain leased space at various dates in January 2022 and March 2022. The lease agreement expires in December 2027 and provides for a one-time option to extend for a period of five additional years. The lease agreement provides the Company with an allowance for tenant improvements of $ 5.3 million that is reimbursed to the Company as construction of improvements occurs. Through December 31, 2022, the Company received $ 4.6 million of the tenant improvement allowance. The monthly base rent will be $ 0.2 million for the first year, beginning in October 2022, and will increase by 3.0 % per year over the initial term. In addition, the Company is obligated to pay for common area maintenance and other costs. Under the terms of the lease agreement, the Company is required to maintain a standby letter of credit of $ 1.1 million at the execution of the lease agreement, reduced to $ 0.9 million in October 2023, and further reduced to $ 0.7 million in October 2024. In June 2022, the Company took possession of temporary office and laboratory space under a short-term lease that terminated in September 2022. Classification of ROU assets and lease liabilities and the weighted-average remaining lease term and discount rate associated with operating leases are as follows (in thousands): As of ROU assets: ROU assets - operating leases $ 3,247 Lease liabilities: Current portion of operating lease liabilities 2,137 Noncurrent portion of operating lease liabilities 6,658 Total lease liabilities $ 8,795 Weighted-average remaining lease term (in years): Operating leases 5.0 Weighted-average discount rate: Operating leases 8.0 % The components of lease costs are as follows (in thousands): Year Ended 2022 2021 Operating lease costs $ 983 $ — Variable lease costs 144 — Short-term lease costs 728 396 Total lease costs $ 1,855 $ 396 The maturities of lease liabilities and reconciliation to the present value of lease liabilities are as follows (in thousands): As of December 31, 2023 $ 2,137 2024 2,201 2025 2,267 2026 2,335 2027 2,405 Total undiscounted lease payments 11,345 Less: lease incentives ( 530 ) Less: imputed interest ( 2,020 ) Total lease liabilities 8,795 Less: current lease liabilities ( 2,137 ) Lease liabilities, net of current portion $ 6,658

Convertible Preferred Stock and

Convertible Preferred Stock and Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Convertible Preferred Stock and Stockholders' Equity (Deficit)	. Convertible Preferred Stock and Stockholders’ Equity Convertible Preferred Stock In connection with the Company's IPO in August 2021, all outstanding shares of the convertible preferred stock were converted into common stock as discussed below. No convertible preferred stock was outstanding as of December 31, 2022 or December 31, 2021. In February 2021, the Company triggered a milestone closing associated with its Series A-1 convertible preferred stock resulting in the issuance of 21,944,874 shares. In March 2021, before the Company effected a 1-for-4.1557 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s convertible preferred stock in July 2021, the Company entered into a convertible preferred stock purchase agreement for the issuance of 35,764,462 shares of Series B convertible preferred stock, $ 0.0001 par value per share, of which 32,958,612 shares of Series B-1 and 2,805,850 shares of Series B-2 were issued. The Series B convertible preferred stock financing resulted in net cash proceeds of $ 92.7 million, net of $ 0.35 million in issuance costs from the sale of 32,958,612 shares of Series B-1 convertible preferred stock at a price of $ 2.82172 per share. In addition, the Convertible Promissory Note of $ 6.5 million that the Company issued in August 2020, including accrued interest as of the date of conversion of $ 0.2 million, was converted into 2,805,850 shares of Series B-2 convertible preferred stock on March 19, 2021 at 85 % of the offering’s share price. Prior to its conversion into common stock in connection with the Company’s IPO in August 2021, the Company’s convertible preferred stock was classified as temporary equity on the Company’s balance sheets in accordance with authoritative guidance. In connection with the Company’s IPO, all outstanding shares of the convertible preferred stock converted into 21,634,898 shares of common stock and the related carrying value was reclassified to common stock and additional paid-in capital. There were no shares of convertible preferred stock outstanding as of the closing of the IPO. On August 2, 2021, the Company amended and restated its certificate of incorporation to authorize 500,000,000 shares of common stock and 50,000,000 shares of preferred stock, which shares of preferred stock are currently undesignated. The Company does not have any outstanding preferred stock as of December 31, 2022. Common Stock As of December 31, 2022 and 2021, of the 500,000,000 authorized shares of common stock, 41,177,706 and 39,429,103 shares were issued, respectively. As of December 31, 2022 and December 31, 2021, shares outstanding, which excludes common stock issued from the early exercise of unvested stock options, were 41,095,564 and 39,175,279 , respectively. On August 15, 2022, the Company entered into an Equity Distribution Agreement (the "Equity Distribution Agreement") with Oppenheimer & Co. Inc. (the "Agent"), pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering price of up to $ 150.0 million from time to time, in “at the market” offerings through the Agent. Sales of the shares of common stock, if any, will be made at prevailing market prices at the time of sale, or as otherwise agreed with the Agent. The Agent will receive a commission from the Company of up to 3.0% of the gross proceeds of any shares of common stock sold under the Equity Distribution Agreement. The Company is not obligated to sell, and the Agent is not obligated to buy or sell, any shares of common stock under the Equity Distribution Agreement. During the three months ended December 31, 2022, the Company sold and issued 980,000 shares of common stock under the Equity Distribution Agreement, resulting in net cash proceeds of $ 9.4 million, net of $ 0.6 million in issuance costs. Equity Incentive Plans In 2017, the Company established a stock option plan (the “2017 Plan”) under which incentives may be granted to officers, employees, directors, consultants and advisors. Awards under the 2017 Plan may consist of restricted stock and incentive and non-qualified stock options to purchase shares of common stock of the Company. During 2021, the Company’s stockholders approved the 2021 Incentive Plan (the “2021 Plan”), which became effective in July 2021. The 2021 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock, dividend equivalents, RSUs and other stock or cash-based awards. The number of shares of the Company’s common stock initially reserved for issuance under the 2021 Plan was 4,600,000 shares; plus the shares of common stock remaining available for issuance under the 2017 Plan as of the effective date of the 2021 Plan, as well as any shares subject to outstanding awards under the 2017 Plan as of the effective date of the 2021 Plan that become available for issuance under the 2021 Plan thereafter in accordance with its terms. The number of shares initially available for issuance increases annually on January 1 of each calendar year beginning in 2022 and ending in and including 2031, equal to the lesser of (A) 5 % of the shares outstanding on the final day of the immediately preceding calendar year and (B) a smaller number of shares as determined by the Company's board of directors. The reserve for the 2021 Plan increased by 2,058,885 shares effective January 1, 2023. No more than 50,000,000 shares of common stock may be issued under the 2021 Plan upon the exercise of incentive stock options. The 2021 Plan is administered by the Board of Directors of the Company or a committee appointed by the Board of Directors, which determines the types of awards to be granted, including the number of shares subject to the awards, the exercise price and the vesting schedule. All option and service-based RSU awards are subject to a time-based vesting period which will generally be four years. Performance-based RSU awards are subject to vesting conditions based on the achievement of specified milestones related to development of vaccine candidates. Certain option and RSU awards provide for accelerated vesting if there is a change in control or if other contractually specified contingencies are met. The term of stock options granted under the 2021 Plan cannot exceed ten years (or five years in the case of incentive stock options granted to certain significant stockholders). Options shall not have an exercise price less than 100 % of the fair market value of the Company’s common stock on the grant date (or 110 % in the case of incentive stock options granted to certain significant stockholders), except with respect to certain substitute awards granted in connection with a corporate transaction. Common stock reserved for future issuance consisted of the following: As of December 31, 2022 Common stock options and restricted stock units granted and outstanding 9,387,963 Shares available for issuance under the equity incentive plans 2,409,593 Shares available for issuance under the 2021 Employee Stock Purchase Plan 706,413 Total common stock reserved for issuance 12,503,969 A summary of the status of the options issued under the Company’s equity incentive plans as of December 31, 2022, and information with respect to the changes in options outstanding is as follows (in thousands, except share and per share data): Options Weighted Average Exercise Weighted Average Remaining Aggregate Balance at December 31, 2021 6,591,727 $ 8.04 Granted 3,112,560 9.66 Exercised ( 395,050 ) 1.48 Forfeited ( 377,233 ) 10.91 Expired ( 547,014 ) 5.32 Balance at December 31, 2022 8,384,990 $ 9.00 8.72 $ 20,499 Vested and expected to vest as of 8,384,990 $ 9.00 8.72 $ 20,499 Vested and exercisable at 2,219,625 $ 8.06 8.31 $ 5,636 Exercisable options in the table above reflect the number of options vested as of the date reported. Options that were granted under the 2017 Plan permitted early exercise. Cash received for early exercise of unvested options is recognized as an other noncurrent liability in the accompanying balance sheet and totaled $ 0.1 million at December 31, 2022. The aggregate intrinsic value in the table above is calculated as the difference between the exercise price of the underlying options and the fair value of the Company’s common stock for all options that were in-the-money as of December 31, 2022. The aggregate intrinsic value of options exercised during the years ended December 31, 2022 and 2021 was $ 5.1 million and $ 1.0 million, respectively. The weighted-average grant date fair value of options granted during the years ended December 31, 2022 and 2021 was $ 7.33 and $ 8.52 per share, respectively. A summary of the status of RSUs issued under the Company’s equity incentive plans as of December 31, 2022, and information with respect to the changes in RSUs outstanding is as follows: Service-based RSUs Performance-based RSUs Units Weighted Average Grant-Date Fair Value Units Weighted Average Grant-Date Fair Value Nonvested at December 31, 2021 388,500 $ 25.96 — $ — Granted 906,271 $ 12.25 60,000 $ 18.74 Vested ( 278,281 ) $ 11.34 ( 24,000 ) $ 10.91 Forfeited ( 49,517 ) $ 16.45 — $ — Nonvested at December 31, 2022 966,973 $ 17.81 36,000 $ 3.08 Expected to vest at December 31, 2022 966,973 $ 17.81 — $ — The total fair value of RSUs vested during the year ended December 31, 2022 was $ 1.6 million. No RSUs vested during the year ended December 31, 2021. The weighted-average grant date fair value of RSUs granted during the year ended December 31, 2021 was $ 25.96 per share. Employee Stock Purchase Plan During 2021, the Company’s stockholders approved the 2021 Employee Stock Purchase Plan (the “ESPP”), which became effective in July 2021. The ESPP permits eligible employees who elect to participate in an offering under the ESPP to have up to 15% of their eligible earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the ESPP. The price of common stock purchased under the ESPP is equal to 85% of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant date of purchase. The number of shares of common stock initially reserved for issuance under the ESPP was 400,000 shares. The number of shares of common stock reserved for issuance under the ESPP increased on January 1, 2022 and will increase each January 1 thereafter through January 1, 2031, in an amount equal to the lower of (1) 1 % of the aggregate number of shares of common stock of the Company outstanding on the final day of the immediately preceding calendar year and (2) such smaller number of shares of common stock as determined by the Board, provided that no more than 15,000,000 shares of our common stock may be issued under the ESPP. The reserve for the ESPP increased by 411,777 shares effective January 1, 2023. During the year ended December 31, 2022, 71,272 shares were purchased by employees under the ESPP, and during the year ended December 31, 2021, 16,606 shares were purchased by employees under the ESPP. Stock-based compensation expense related to the ESPP for the years ended December 31, 2022 and 2021 was $ 0.3 million and $ 0.1 million, respectively. Stock-Based Compensation Expense Stock-based compensation expense for all equity awards and the ESPP, has been reported in the statements of operations and comprehensive loss as follows (in thousands): Year Ended 2022 2021 Research and development $ 8,123 $ 2,710 General and administrative 13,571 26,321 Total $ 21,694 $ 29,031 The Company recognizes compensation expense for options and RSU awards based on their grant date fair value. The compensation expense is recognized over the requisite service period on a straight-line basis. The fair value of RSUs is equal to the closing stock price on the date of grant. The fair value of each stock option granted was estimated using the Black-Scholes option pricing model. The assumptions used in the Black-Scholes option pricing model to estimate the fair value of the stock option grants issued during years ended were as follows: Year Ended 2022 2021 Risk-free rate of interest 1.43 %- 4.15 % 0.63 %- 1.34 % Expected term (years) 5.27 - 6.08 years 5.77 - 6.08 years Expected stock price volatility 89.3 % - 118.1 % 84.2 % - 90.9 % Dividend yield 0 % 0 % As of December 31, 2022, the unrecognized compensation cost related to outstanding stock options and RSU awards was $ 43.4 million and $ 14.1 million, respectively, and is expected to be recognized as expense over a weighted-average period of approximately 2.68 years. On August 4, 2021, as a result of the death of Tadataka (Tachi) Yamada, M.D., the Company's former Chairman, the Company's Board of Directors decided to accelerate the vesting of all of Dr. Yamada's previously unvested stock options as of the date of his death. The Company accelerated the vesting of 611,639 stock options, with exercise prices ranging from $ 0.83 to $ 5.90 per share, resulting in incremental non-cash, stock-based compensation of $ 21.0 million being recorded in 2021 as general and administrative expense.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The reconciliations of the U.S. statutory federal income tax rates to the Company's effective tax rates were as follows: Year Ended 2022 2021 U.S. federal statutory income tax rate 21.0 % 21.0 % Adjustments for the tax effects of: State income taxes, net of federal tax 1.1 1.0 Other permanent differences 0.4 ( 0.4 ) Research and development tax credits 3.4 3.1 Research and development credit permanent adjustment — ( 0.6 ) Stock-based compensation ( 2.2 ) ( 1.6 ) Uncertain tax positions ( 0.9 ) ( 0.8 ) Change in valuation allowance ( 22.8 ) ( 21.7 ) Effective income tax rate — % — % Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The significant components of our deferred tax assets and liabilities are as follows (in thousands): As of December 31, 2022 2021 Deferred tax assets Net operating loss carryforwards $ 17,304 $ 12,623 Capitalized research and development 11,731 — Research and development credits 4,599 2,349 Deferred revenue — 126 Operating lease liabilities 1,951 — Stock-based compensation 2,203 5,192 Other 712 533 Total deferred tax assets 38,500 20,823 Deferred tax liabilities Property and equipment ( 1,135 ) — Right-of-use assets – operating leases ( 720 ) — Other ( 269 ) ( 280 ) Total deferred tax liabilities ( 2,124 ) ( 280 ) Less: valuation allowance ( 36,376 ) ( 20,543 ) Net deferred tax assets $ — $ — The Tax Cuts and Jobs Act enacted in December 2017 contained a provision that 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. The Company has included the impact of this provision, which results in a deferred tax asset of approximately $ 11.7 million as of December 31, 2022. Due to the uncertainty surrounding the realization of deductible tax attributes in future tax returns, the Company has recorded a valuation allowance against its net deferred tax assets as of December 31, 2022 and 2021. Utilization of the net operating loss carryforwards is dependent on future taxable income. As such, realization is not assured, and a valuation allowance has been established. The valuation allowance for deferred tax assets was approximately $ 36.4 million as of December 31, 2022, an increase of $ 15.8 million during the year ended December 31, 2022. The Company has total net operating loss carryforwards for U.S. federal income tax and state purposes of approximately $ 76.2 million and $ 30.8 million, respectively, as of December 31, 2022 which begin to expire in 2037 and 2035 , respectively. Federal net operating losses generated after January 1, 2018 will be carried forward indefinitely. The Company has federal research and development tax credit carryforwards of approximately $ 5.9 million as of December 31, 2022, which begin to expire in 2037 . Additionally, the Company has state research and development credit carryforwards of approximately $ 0.3 million as of December 31, 2022, which begin to expire in 2032 . The operating loss carryforwards and research and development tax credits may be limited due to a change in control in the Company’s ownership as defined by the Internal Revenue Code Sections 382 and 383. The Company files federal and state income tax returns. The Company is not currently under examination but is open to audit by the I.R.S. and state tax authorities for tax years beginning in 2017. The resolutions of any examinations are not expected to be material to these financial statements. As of December 31, 2022, there are no penalties or accrued interest recorded in the financial statements. 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, 2022 2021 Unrecognized tax benefits, beginning of year $ 758 $ 263 Additions based on tax positions relating to current year 775 495 Additions based on tax positions relating to prior year 14 — Unrecognized tax benefits, end of year $ 1,547 $ 758 The Company does not believe it is reasonably possible that its unrecognized tax benefits will change materially in the next twelve months.

Employee Savings Plan

Employee Savings Plan	Dec. 31, 2022
Postemployment Benefits [Abstract]
Employee Saving Plan	11. Employee Savings Plan The Company has a defined contribution 401(k) savings plan for those employees who meet minimum eligibility requirements. Under the terms of the plan, eligible employees may contribute up to 90 % of their annual compensation to the plan, subject to Internal Revenue Service limitations. The Company may also, at its sole discretion, make contributions to the plan. The Company contributed $ 0.1 million to the plan during the year ended December 31, 2022. The Company did no t make any contributions to the plan during 2021.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported balances of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates are used for, but not limited to, stock-based compensation, derivative liability, the timing of research and development accruals, and income taxes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents, restricted cash, and short-term investments. 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 maintains insured cash sweep accounts where balances are maintained in interest bearing demand accounts. The Company has not realized any losses on these deposits, and management believes that the Company is not exposed to significant credit risk due to the financial positions of the respective depository institutions in which those deposits are held, and its short-term investments are in high credit quality securities including U.S. Treasury and U.S. Agency securities, commercial paper, and highly rated corporate debt securities
Comprehensive Loss	Comprehensive Loss Comprehensive loss comprises net loss and certain changes in equity excluded from net loss. For the year ended December 31, 2022, other comprehensive loss included unrealized losses on the Company's short-term investments in available-for-sale debt securities. The Company’s comprehensive loss was the same as its reported net loss for the year ended December 31, 2021.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The accounting guidance defines fair value, establishes a consistent framework for measuring fair value, and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of prepaid expenses and other assets, accounts payable, and accrued and other current liabilities are considered to be representative of their respective fair values due to their short maturities.
Cash	Cash and Cash Equivalents and Restricted Cash Cash and cash equivalents consists of deposits with commercial banks in checking and interest-bearing accounts, highly rated money market funds, and all highly liquid investments with an original maturity of 90 days or less at the time of purchase. At December 31, 2022 and 2021, restricted cash includes cash deposited in a collateral account to support a letter of credit issued as security for the Company's operating lease to rent office and laboratory space in Seattle, Washington. At December 31, 2021, restricted cash also includes payments received under the Grant Agreement (as defined in Note 4) with the Bill & Melinda Gates Foundation (“BMGF”). Investments Investments include U.S. Treasury and U.S. Agency securities, commercial paper, and corporate debt securities with a final maturity of each security of less than one year. These investments are classified as available-for-sale debt securities, which are recorded at fair value based on quoted prices in active markets. The Company classifies investments maturing within one year of the reporting date as short-term investments. The Company periodically evaluates whether declines in the fair values of its investments below their amortized cost basis are other-than-temporary. This evaluation considers qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs, including whether the Company has plans to sell the security or whether it is more likely than not the Company will be required to sell any investment before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the investments, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the investment. If the estimated fair value of a debt security is below its amortized cost basis, the Company evaluates whether credit losses exist for the related securities. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment recognized in net loss. Unrealized gains and losses that are unrelated to credit deterioration are reported in other comprehensive loss. The Company recognizes purchase premiums and discounts as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other-than-temporary are reflected in the statements of operations and comprehensive loss using the specific-identification method.
Property and equipment, net	Property and equipment, net Property and equipment, net is stated at cost, net of accumulated depreciation and is depreciated using the straight-line method over the estimated useful lives of the assets, generally two to five years, while leasehold improvements are depreciated over the shorter of their estimated useful lives or the related lease term .
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company regularly reviews the carrying value and estimated lives of its long-lived assets, including property and equipment to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. Should an impairment exist, the impairment loss would be measured based on the excess over the carrying amount of the asset’s fair value. The Company has no t recognized any impairment losses from inception through December 31, 2022.
Derivative Liability, Convertible Notes Discount and Amortization	Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible note (see Note 7) had conversion and redemption features that met the definition of an embedded derivative and were therefore subject to bifurcation and derivative accounting. The initial recognition of the fair value of the derivative resulted in a discount to the convertible note, with a corresponding derivative liability. The discount to the convertible note was amortized using the effective interest method. The amortization of the discount is included in interest and other expense in the statements of operations and comprehensive loss. The derivative liability related to these features was recorded at estimated fair value and remeasured on a recurring basis. Any changes in fair value were reflected as change in fair value of derivative liability in the statements of operations and comprehensive loss at each reporting date while such instruments were outstanding. The derivative liability was settled in March 2021 upon conversion of the underlying convertible note into Series B convertible preferred stock, resulting in a loss on extinguishment of convertible promissory note
Leases	Leases At the inception of a contractual arrangement, the Company determines whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. If both criteria are met, the Company records the associated lease liability and corresponding right-of-use ("ROU") asset upon commencement of the lease using the implicit rate or a discount rate based on a credit-adjusted secured borrowing rate commensurate with the term of the lease. The Company additionally evaluates leases at their inception to determine if they are to be accounted for as an operating lease or a finance lease. A lease is accounted for as a finance lease if it meets one of the following five criteria: the lease has a purchase option that is reasonably certain of being exercised, the present value of the future cash flows is substantially all of the fair market value of the underlying asset, the lease term is for a significant portion of the remaining economic life of the underlying asset, the title to the underlying asset transfers at the end of the lease term, or if the underlying asset is of such a specialized nature that it is expected to have no alternative uses to the lessor at the end of the term. Leases that do not meet the finance lease criteria are accounted for as an operating lease. Operating lease assets represent a right to use an underlying asset for the lease term and operating lease liabilities represent an obligation to make lease payments arising from the lease. Operating lease liabilities with a term greater than one year and their corresponding ROU assets are recognized on the balance sheet at the commencement date of the lease based on the present value of lease payments over the expected lease term. Certain adjustments to the ROU asset may be required for items such as initial direct costs paid or incentives received. As the Company’s leases do not typically provide an implicit rate, the Company utilizes the appropriate incremental borrowing rate, determined as the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term and in a similar economic environment. Lease cost is recognized on a straight-line basis over the lease term and variable lease payments are recognized as operating expenses in the period in which the obligation for those payments is incurred. Variable lease payments primarily include common area maintenance, utilities, real estate taxes, insurance, and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company has elected the practical expedient to not separate lease and non-lease components .
Grant Revenue	Grant Revenue The Company’s revenue consists of revenue under its prior Grant Agreement with BMGF (see Note 4). The Company was reimbursed for certain costs that support development activities, including the Company’s clinical trial notification (“CTN”) preparations for and planned first-in-human Phase 1/2 clinical trial of the Company's former IVX-411 SARS-CoV-2 vaccine in Australia. The Company’s Grant Agreement did not provide a direct economic benefit to BMGF. Rather, the Company entered into an agreement with BMGF to make a certain amount of any resulting vaccine available and accessible at affordable pricing to people in certain low- and middle-income countries. The Company assessed this cost reimbursement agreement to determine if the agreement should be accounted for as an exchange transaction or a contribution. Such an agreement is accounted for as a contribution if the resource provider does not receive commensurate value in return for the assets transferred. Contributions are recognized as grant revenue when all donor-imposed conditions have been met.
Accrued Research and Development Expense	Accrued Research and Development Expense The Company is required to estimate its obligation for expenses incurred under contracts with vendors, consultants, and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its financial statements by recognizing those expenses in the periods in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical study or clinical trial, as measured by the timing of various aspects of the study, trial or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel and third-party service providers as to the progress of studies or trials, or other services being conducted. To date, the Company has had no material differences between its estimates of such expenses and the amounts actually incurred. During the course of a study or trial, the Company adjusts its expense recognition if actual results differ from its estimate. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed.
Research and Development	Research and Development Research and development costs are expensed as incurred and consist primarily of external and internal costs related to the development of vaccine candidates, including salaries and benefits, stock-based compensation, facilities and depreciation, contracted research, consulting arrangements, and other expenses incurred to sustain the Company’s research and development programs
Interest Income	Interest Income Interest income consists of interest income earned on short-term investments in debt securities and interest bearing demand accounts.
Liability For Early Exercise Of Stock Options	Liability for Early Exercise of Stock Options Certain individuals were granted the ability to early exercise their stock options. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest in accordance with the original vesting schedule. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options on the accompanying balance sheets and will be reclassified as common stock and additional paid-in capital as the shares vest. Unvested shares issued under early exercise provisions subject to repurchase by the Company totaled 82,142 and 253,824 shares as of December 31, 2022 and 2021, respectively. As of December 31, 2022 and 2021, the Company recorded $ 0.1 million and $ 0.2 million respectively, related to shares issued with repurchase rights as other noncurrent liabilities in the accompanying balance sheets.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee, officer, director and non-employee stock option grants, estimated in accordance with the applicable accounting guidance, recognized on a straight-line basis over the vesting period. The vesting period generally approximates the expected service period of the awards. The Company recognizes forfeitures as they occur. The fair value of restricted stock units (“RSUs”) is based on the closing price of the Company's common stock on the grant date. The fair value of stock options is estimated using the Black-Scholes option pricing model. The Black-Scholes option pricing model uses inputs which are assumptions that generally require judgment. These assumptions include: ▪ Fair Value of Common Stock . The grant date fair value of the Company’s common stock is determined based on its closing price. ▪ Expected Term . The expected term represents the period that the options granted are expected to be outstanding. The expected term of stock options issued is determined using the simplified method (based on the average of the vesting term and the original contractual term) as the Company has concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term. ▪ Expected Volatility . Given the Company’s limited historical stock price volatility data, the Company derived the expected volatility from the average historical volatilities over a period approximately equal to the expected term of comparable publicly traded companies within the Company’s peer group that were deemed to be representative of future stock price trends as the Company has limited trading history for its common stock. 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. ▪ 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 options. ▪ Expected Dividend Yield . The Company has never paid dividends on its common stock and does not anticipate paying any dividends in the foreseeable future. Therefore, the Company used an expected dividend yield of zero. Significant changes to the key assumptions underlying the factors used could result in different fair values of stock options at each valuation date.
Commitments and Contingencies	Commitments and Contingencies The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has been incurred, and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount the Company accrues the minimum amount in the range. In the event the Company becomes subject to claims or suits arising in the ordinary course of business, the Company would accrue a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. The Company has not recorded any such liabilities at either December 31, 2022 or 2021.
Income Tax	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. As of December 31, 2022 and 2021, the Company maintained valuation allowances against its deferred tax assets as the Company concluded it had not met the “more likely than not” to be realized threshold. Changes in the valuation allowance when they are recognized in the provision for income taxes may result in a change in the estimated annual effective tax rate. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. As of December 31, 2022, the Company had no accrued interest or penalties.
Net Loss Per Share	Net Loss Per Share Basic net loss per share 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. Diluted net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock and common stock equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding stock options and restricted stock units under the Company’s equity incentive plan and have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. The following tables summarize the computation of the basic and diluted net loss per share (in thousands, except share and per share data): Year Ended 2022 2021 Numerator: Net loss $ ( 91,758 ) $ ( 66,971 ) Denominator: Weighted-average common shares outstanding, basic and diluted 39,725,131 17,965,894 Net loss per share, basic and diluted $ ( 2.31 ) $ ( 3.73 ) The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. Year Ended 2022 2021 Common stock options and restricted stock units 9,387,963 6,591,727 ESPP shares 66,488 16,606 Unvested common stock 82,142 253,824 Total 9,536,593 6,862,157
Segments	Segments The Company has determined that it operates and manages one operating segment, which is the business of researching and developing vaccines against infectious diseases. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources. All assets of the Company are located in the United States.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Standards In December 2019, the FASB issued ASU 2019-12, Income Taxes—Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance to reduce complexity in certain areas, such as requiring that an entity reflect the effect of an enacted change in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. The new standard is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022 for all non-public entities, with early adoption permitted, and is effective for fiscal years beginning after December 15, 2020, including interim periods within those annual periods for public entities. Early adoption is permitted. The Company adopted ASU 2019-12 on January 1, 2021 and the standard did not have a material impact on its financial statements and related disclosures. Recently Issued Accounting Standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02 ("ASU 2016-13"). 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. ASU 2016-13 will become effective beginning January 1, 2023, with early adoption permitted. The adoption of ASU 2016-13 did not have a material impact on the Company's financial condition, results of operations, cash flows, and financial statement disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Computation of Basic and Diluted Net Loss Per Share	The following tables summarize the computation of the basic and diluted net loss per share (in thousands, except share and per share data): Year Ended 2022 2021 Numerator: Net loss $ ( 91,758 ) $ ( 66,971 ) Denominator: Weighted-average common shares outstanding, basic and diluted 39,725,131 17,965,894 Net loss per share, basic and diluted $ ( 2.31 ) $ ( 3.73 )
Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. Year Ended 2022 2021 Common stock options and restricted stock units 9,387,963 6,591,727 ESPP shares 66,488 16,606 Unvested common stock 82,142 253,824 Total 9,536,593 6,862,157

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value, Liabilities Measured on Recurring Basis	The following table summarizes, by major security type, the Company's cash, cash equivalents, and investments that are measured at fair value on a recurring basis by level within the fair value hierarchy as of December 31, 2022 (in thousands): December 31, 2022 Fair Value Hierarchy Level Amortized Cost Gross Unrealized Gross Unrealized Fair Market Value Assets: Cash and cash equivalents: Cash Level 1 $ 23,376 $ — $ — $ 23,376 Money market funds Level 1 35,470 — — 35,470 Total cash and cash equivalents 58,846 — — 58,846 Investments: U.S. Treasury securities Level 1 82,277 3 ( 331 ) 81,949 U.S. Agency securities Level 2 14,044 28 — 14,072 Corporate debt securities and commercial paper Level 2 63,543 — ( 103 ) 63,440 Total investments 159,864 31 ( 434 ) 159,461 Total assets measured at fair value on a recurring basis $ 218,710 $ 31 $ ( 434 ) $ 218,307
Fair Value Measurement Inputs and Valuation Techniques	The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the derivative liability: March 19, 2021 Probability of financing 100 % Probability of dissolution — Time to liquidity (years) — Discount rate 7.6 %
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a reconciliation of the fair value of the derivative liability using Level 3 significant unobservable inputs (in thousands): Derivative Liability Fair value at December 31, 2020 $ ( 1,604 ) Change in fair value of embedded derivative liability ( 205 ) Reclassification of derivative liability into convertible preferred stock resulting from conversion of convertible promissory note 1,809 Fair value at December 31, 2021 $ —

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of property and equipment	Property and equipment, net, consists of the following (in thousands): As of December 31, 2022 2021 Laboratory equipment $ 2,192 $ 856 Leasehold improvements 9,660 — Office furniture and equipment 608 — Construction in progress — 303 Property and equipment, cost 12,460 1,159 Accumulated depreciation ( 943 ) ( 83 ) Property and equipment, net $ 11,517 $ 1,076
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consist of the following (in thousands): As of December 31, 2022 2021 Taxes payable $ 80 $ — Accrued paid time off 664 342 Accrued bonus 3,135 2,216 Other accrued liabilities 4,512 1,977 Accrued 401k 324 156 ESPP liability 44 66 Total accrued and other current liabilities $ 8,759 $ 4,757

Convertible Promissory Note (Ta

Convertible Promissory Note (Tables)	12 Months Ended
	Dec. 31, 2022
Convertible Promissory Note [Abstract]
Summary Of Interest Expense Of Convertible Promissory Note	Interest expense incurred in connection with the Convertible Promissory Note consisted of the following (in thousands): Year Ended December 31, 2021 Coupon interest at 6% $ 86 Accretion of discount and amortization of issuance costs 177 Total interest expense on Convertible Promissory Note $ 263

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Classified of ROU assets and lease liabilities and weighted average remaining lease term	Classification of ROU assets and lease liabilities and the weighted-average remaining lease term and discount rate associated with operating leases are as follows (in thousands): As of ROU assets: ROU assets - operating leases $ 3,247 Lease liabilities: Current portion of operating lease liabilities 2,137 Noncurrent portion of operating lease liabilities 6,658 Total lease liabilities $ 8,795 Weighted-average remaining lease term (in years): Operating leases 5.0 Weighted-average discount rate: Operating leases 8.0 %
Schedule of Component of Lease Cost	The components of lease costs are as follows (in thousands): Year Ended 2022 2021 Operating lease costs $ 983 $ — Variable lease costs 144 — Short-term lease costs 728 396 Total lease costs $ 1,855 $ 396
Schedule of Maturities of Lease Liabilities	The maturities of lease liabilities and reconciliation to the present value of lease liabilities are as follows (in thousands): As of December 31, 2023 $ 2,137 2024 2,201 2025 2,267 2026 2,335 2027 2,405 Total undiscounted lease payments 11,345 Less: lease incentives ( 530 ) Less: imputed interest ( 2,020 ) Total lease liabilities 8,795 Less: current lease liabilities ( 2,137 ) Lease liabilities, net of current portion $ 6,658

Convertible Preferred Stock a_2

Convertible Preferred Stock and Stockholders' Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Schedule of common stock reserved for future issuance	Common stock reserved for future issuance consisted of the following: As of December 31, 2022 Common stock options and restricted stock units granted and outstanding 9,387,963 Shares available for issuance under the equity incentive plans 2,409,593 Shares available for issuance under the 2021 Employee Stock Purchase Plan 706,413 Total common stock reserved for issuance 12,503,969
Summary of the Status of the Options Issued Under the Plan	A summary of the status of the options issued under the Company’s equity incentive plans as of December 31, 2022, and information with respect to the changes in options outstanding is as follows (in thousands, except share and per share data): Options Weighted Average Exercise Weighted Average Remaining Aggregate Balance at December 31, 2021 6,591,727 $ 8.04 Granted 3,112,560 9.66 Exercised ( 395,050 ) 1.48 Forfeited ( 377,233 ) 10.91 Expired ( 547,014 ) 5.32 Balance at December 31, 2022 8,384,990 $ 9.00 8.72 $ 20,499 Vested and expected to vest as of 8,384,990 $ 9.00 8.72 $ 20,499 Vested and exercisable at 2,219,625 $ 8.06 8.31 $ 5,636
Summary of the RSU under Equity incentive plan	A summary of the status of RSUs issued under the Company’s equity incentive plans as of December 31, 2022, and information with respect to the changes in RSUs outstanding is as follows: Service-based RSUs Performance-based RSUs Units Weighted Average Grant-Date Fair Value Units Weighted Average Grant-Date Fair Value Nonvested at December 31, 2021 388,500 $ 25.96 — $ — Granted 906,271 $ 12.25 60,000 $ 18.74 Vested ( 278,281 ) $ 11.34 ( 24,000 ) $ 10.91 Forfeited ( 49,517 ) $ 16.45 — $ — Nonvested at December 31, 2022 966,973 $ 17.81 36,000 $ 3.08 Expected to vest at December 31, 2022 966,973 $ 17.81 — $ —
Schedule of Stock-based Compensation Expense for All Equity Awards	Stock-based compensation expense for all equity awards and the ESPP, has been reported in the statements of operations and comprehensive loss as follows (in thousands): Year Ended 2022 2021 Research and development $ 8,123 $ 2,710 General and administrative 13,571 26,321 Total $ 21,694 $ 29,031
Summary of Assumptions Used in Black-Scholes Model	The fair value of each stock option granted was estimated using the Black-Scholes option pricing model. The assumptions used in the Black-Scholes option pricing model to estimate the fair value of the stock option grants issued during years ended were as follows: Year Ended 2022 2021 Risk-free rate of interest 1.43 %- 4.15 % 0.63 %- 1.34 % Expected term (years) 5.27 - 6.08 years 5.77 - 6.08 years Expected stock price volatility 89.3 % - 118.1 % 84.2 % - 90.9 % Dividend yield 0 % 0 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Reconciliation of Federal Statutory Income Tax Rate and Effective Income Tax Rate	The reconciliations of the U.S. statutory federal income tax rates to the Company's effective tax rates were as follows: Year Ended 2022 2021 U.S. federal statutory income tax rate 21.0 % 21.0 % Adjustments for the tax effects of: State income taxes, net of federal tax 1.1 1.0 Other permanent differences 0.4 ( 0.4 ) Research and development tax credits 3.4 3.1 Research and development credit permanent adjustment — ( 0.6 ) Stock-based compensation ( 2.2 ) ( 1.6 ) Uncertain tax positions ( 0.9 ) ( 0.8 ) Change in valuation allowance ( 22.8 ) ( 21.7 ) Effective income tax rate — % — %
Schedule Of Components Of Deferred Tax Assets And Liabilities	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The significant components of our deferred tax assets and liabilities are as follows (in thousands): As of December 31, 2022 2021 Deferred tax assets Net operating loss carryforwards $ 17,304 $ 12,623 Capitalized research and development 11,731 — Research and development credits 4,599 2,349 Deferred revenue — 126 Operating lease liabilities 1,951 — Stock-based compensation 2,203 5,192 Other 712 533 Total deferred tax assets 38,500 20,823 Deferred tax liabilities Property and equipment ( 1,135 ) — Right-of-use assets – operating leases ( 720 ) — Other ( 269 ) ( 280 ) Total deferred tax liabilities ( 2,124 ) ( 280 ) Less: valuation allowance ( 36,376 ) ( 20,543 ) Net deferred tax assets $ — $ —
Summary of Unrecognized Tax Benefits	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, 2022 2021 Unrecognized tax benefits, beginning of year $ 758 $ 263 Additions based on tax positions relating to current year 775 495 Additions based on tax positions relating to prior year 14 — Unrecognized tax benefits, end of year $ 1,547 $ 758 The Company does not believe it is reasonably possible that its unrecognized tax benefits will change materially in the next twelve months.

Description of Business - Addit

Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Aug. 02, 2021	Aug. 31, 2021	Jul. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Subsidiary Sale Of Stock [Line Items]
Stock split			1-for-4.1557	1-for-4.1557
Sale of common stock				41,177,706	39,429,103
Proceeds from initial public offering, net of offering costs				$ 0	$ 190,738
Preferred stock, shares outstanding				0	0
Accumulated Deficit				$ 185,827	$ 94,069
Cash and cash equivalents restricted cash				218,300
Cash				58,846	$ 279,082
Restricted Cash				$ 1,100
IPO [Member]
Subsidiary Sale Of Stock [Line Items]
Sale of common stock	12,133,333
Offering price per share	$ 15
Additional shares purchasable by underwriters	1,819,999
Proceeds from initial public offering, net of offering costs	$ 190,700
Preferred stock, shares outstanding	89,908,215
Common stock converted	21,634,898	21,634,898

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020
Derivatives liability, carrying value	$ 1,800,000
Restricted Cash	1,100,000
Impairment losses	$ 0
Number of shares subject to repurchase | shares	82,142	253,824
Liabilities with shares issued with repurchase rights	$ 100	$ 200
Accrued interest and penalties	$ 0
Number Of Reporting Units | Segment	1
Lease agreement option to extend	the Company entered into a 12-month lease agreement with renewal options
Right-of-use assets operating leases	$ 3,247,000	$ 0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Minimum [Member]
Property and equipment useful lives of assets	2 years
Maximum [Member]
Property and equipment useful lives of assets	5 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (91,758)	$ (66,971)
Denominator:
Weighted-average common shares outstanding, basic and diluted	39,725,131	17,965,894
Weighted-average common shares outstanding, basic and diluted	39,725,131	17,965,894
Net loss per share, basic and diluted	$ (2.31)	$ (3.73)
Net loss per share, basic and diluted	$ (2.31)	$ (3.73)

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common equivalent shares	9,536,593	6,862,157
ESPP Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common equivalent shares	66,488	16,606
Stock Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common equivalent shares	9,387,963	6,591,727
Unvested Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common equivalent shares	82,142	253,824

Fair value measurements - Sched

Fair value measurements - Schedule of Fair Value Liabilities Measured on Recurring Basis (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 218,710
Gross Unrealized Gains	31
Gross Unrealized Losses	(434)
Fair Market Value	218,307
Cash and Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	58,846
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Market Value	58,846
Investment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	159,864
Gross Unrealized Gains	31
Gross Unrealized Losses	(434)
Fair Market Value	159,461
Level 1 | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Cash [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	23,376
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Market Value	23,376
Level 1 | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	35,470
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Market Value	35,470
Level 1 | Fair Value, Recurring [Member] | Investment [Member] | U.S. Treasury Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	82,277
Gross Unrealized Gains	3
Gross Unrealized Losses	(331)
Fair Market Value	81,949
Level 2 | Fair Value, Recurring [Member] | Investment [Member] | U.S. Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	14,044
Gross Unrealized Gains	28
Gross Unrealized Losses	0
Fair Market Value	14,072
Level 2 | Fair Value, Recurring [Member] | Investment [Member] | Corporate Debt Securities and Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	63,543
Gross Unrealized Gains	0
Gross Unrealized Losses	(103)
Fair Market Value	$ 63,440

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 19, 2021	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unrealized Loss on Securities		$ 90,300
Loss on extinguishment of convertible promissory note		0	$ 754
Series B-2 Convertible Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Promissory note and derivative liability conversion into share	2,805,850
Convertible preferred stock issued upon conversion	2,805,850
Operating Expense [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of embedded derivative liability		200
Operating Expense [Member] | Series B-2 Convertible Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on extinguishment of convertible promissory note		$ 800

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Significant Unobservable Inputs Used in the Fair Value Measurements for the Derivative Liability (Details)	Mar. 19, 2021
Measurement Input Probability Of Financing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liability	100
Measurement Input Probability Of Dissolution [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liability	0
Measurement Input, Expected Term [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liability	0
Measurement Input, Discount Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liability	0.76

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Reconciliation of the Fair Value of the Derivative Liability Using Level 3 Significant Unobservable Inputs (Details) - Level 3 $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	$ (1,604)
Change in the fair value of the derivative liability	(205)
Reclassification of derivative liability into convertible preferred stock resulting from conversion of convertible promissory note	1,809
Ending balance	$ 0

Grant Agreement - Additional In

Grant Agreement - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Grant Agreement [Line Items]
Restricted Cash	$ 1,100	$ 1,100
BMGF Grant
Grant Agreement [Line Items]
Grant Received	10,000	10,000	$ 10,000
Funding received		0	6,000
Revenue from grant		600	7,800
Deferred revenue	$ 0	$ 0	$ 600

Balance Sheet Details -Addition

Balance Sheet Details -Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Depreciation expenses	$ 860	$ 82

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of property and equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property and Equipment [Line Items]
Property and equipment, cost	$ 12,460	$ 1,159
Accumulated depreciation	(943)	(83)
Property and equipment, net, Total	11,517	1,076
Laboratory equipment [Member]
Property and Equipment [Line Items]
Property and equipment, cost	2,192	856
Construction in progress [Member]
Property and Equipment [Line Items]
Property and equipment, cost	0	303
Leasehold Improvements [ Member]
Property and Equipment [Line Items]
Property and equipment, cost	9,660	0
Office furniture and equipment [ Member]
Property and Equipment [Line Items]
Property and equipment, cost	$ 608	$ 0

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Taxes payable	$ 80	$ 0
Accrued paid time off	664	342
Accrued bonus	3,135	2,216
Other accrued liabilities	4,512	1,977
Accrued 401k	324	156
ESPP liability	44	66
Total accrued and other current liabilities	$ 8,759	$ 4,757

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Aug. 01, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee	$ 100
Common stock, shares issued	41,177,706	39,429,103
NIH Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee	$ 100,000
Potential milestone payments	8,600
NIH Agreement | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee		$ 200
U W Two Thousand And Eighteen Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued			192,276
Potential Payments For Future Development Regulatory And Sales Based Milestones	1,350
Total Milestone Payments	12,200
U W Two Thousand And Eighteen And U W Two Thousand And Twenty Agreement | License | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee	500	200
U T Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payments	4,600
U T Agreement | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee	100
UW Flu License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee		$ 100
Aggregate Payments Related To Cumulative Net Sales Thresholds	$ 6,400
License Agreement Expiry Year	2041
UW Flu License Agreement | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment Of License Fee	$ 200

Convertible Promissory Note - A

Convertible Promissory Note - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Mar. 19, 2021	Aug. 31, 2020	Dec. 31, 2022	Dec. 31, 2021
Debt Conversion [Line Items]
Convertible promissory note issued		$ 6,500
Accrued interest rate, per annum		6%
Promissory note maturity period		2 years	2 years
Derivatives liability, carrying value			$ 1,800
Debt discount interest rate, effective percentage			23.80%
Loss on extinguishment of convertible promissory note			$ 0	$ 754
Common Stock [Member]
Debt Conversion [Line Items]
Payments of Debt Issuance Costs			$ 600
Convertible Promissory Note
Debt Conversion [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 140,000
Loss on extinguishment of convertible promissory note				$ 800
Series A3 Convertible Preferred Stock | Convertible Promissory Note
Debt Conversion [Line Items]
Share price, percentage		85%
Series B-2 Convertible Preferred Stock [Member]
Debt Conversion [Line Items]
Promissory note and derivative liability conversion into share	2,805,850
Shares issued price per share	$ 2.39846
Minimum [Member] | Series A3 Convertible Preferred Stock | Convertible Promissory Note
Debt Conversion [Line Items]
Proceeds from Convertible Debt		$ 5,000

Convertible Promissory Note - S

Convertible Promissory Note - Summary of Interest Expense of Convertible Promissory Note (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Convertible Promissory Note [Abstract]
Coupon interest at 6%	$ 86
Accretion of discount and amortization of issuance costs	177
Total interest expense on Convertible Promissory Note	$ 263

Leases (Additional Information)

Leases (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Lease agreement option to extend	the Company entered into a 12-month lease agreement with renewal options
Lease Agreements [Member]
Lessee, Lease, Description [Line Items]
Lease agreement option to extend		The lease agreement expires in December 2027 and provides for a one-time option to extend for a period of five additional years.
Allowance for tenant improvements	$ 4.6	$ 5.3
Monthly base rent		$ 0.2
Monthly base rent yearly increase percentage		3%
Lease Agreements [Member] | Standby Letters of Credit [Member]
Lessee, Lease, Description [Line Items]
Standby letters of credit		$ 1.1
Lease Agreements [Member] | Second Anniversary [Member]
Lessee, Lease, Description [Line Items]
Standby letters of credit		0.7
Lease Agreements [Member] | First Anniversary [Member]
Lessee, Lease, Description [Line Items]
Standby letters of credit		$ 0.9

Leases - Classified of ROU asse

Leases - Classified of ROU assets and lease liabilities and weighted average remaining lease term (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Right-of-use assets operating leases	$ 3,247	$ 0
Current portion of operating lease liabilities	2,137	0
Noncurrent portion of operating lease liabilities	6,658	$ 0
Total lease liabilities	$ 8,795
Weighted-average remaining lease term (in years): Operating leases	5 years
Weighted-average discount rate: Operating leases	8%

Leases - Schedule of Component

Leases - Schedule of Component of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease costs	$ 983	$ 0
Variable lease costs	144	0
Short-term lease costs	728	396
Total lease costs	$ 1,855	$ 396

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
2023	$ 2,137
2024	2,201
2025	2,267
2026	2,335
2027	2,405
Total undiscounted lease payments	11,345
Less: lease incentives	(530)
Less: imputed interest	(2,020)
Total lease liabilities	8,795
Less: current lease liabilities	(2,137)	$ 0
Operating lease liabilities, net of current portion	$ 6,658	$ 0

Convertible Preferred Stock a_3

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended				12 Months Ended
	Aug. 04, 2021	Aug. 02, 2021	Mar. 19, 2021	Aug. 31, 2021	Jul. 31, 2021	Feb. 28, 2021	Aug. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Aug. 15, 2022
Class Of Stock [Line Items]
weighted-average grant date fair value of RSUs granted per share									$ 25.96
Weight granted fair value Nonvested Granted								$ 7.33	$ 8.52
aggregate intrinsic value of options exercised								$ 5,100	$ 1,000
Common stock aggregate offering price										$ 150,000
Convertible Notes Payable								$ 6,500
Reverse Stock Split					1-for-4.1557			1-for-4.1557
Preferred stock, shares outstanding								0	0
Common stock, shares authorized		500,000,000						500,000,000	500,000,000
Preferred stock, shares authorized		50,000,000
Proceeds from issuance of convertible preferred stock, net of issuance costs								$ 0	$ 113,634
Convertible promissory note issued							$ 6,500
Convertible preferred stock								12,503,969
Sale of common stock								41,177,706	39,429,103
Common Stock Shares Outstanding								41,095,564	39,175,279
Common stock, par value								$ 0.0001	$ 0.0001
Granted								3,112,560
Compensation expense recognition vesting period								2 years 8 months 4 days
Stock-based compensation								$ 21,694	$ 29,031
Stock-based compensation expense related to the ESPP								21,694	29,031
Board of Directors Chairman
Class Of Stock [Line Items]
Accelerated vesting of shares	611,639
Exercise price range, lower range limit	$ 0.83
Exercise price range, upper range limit	$ 5.90
Stock-based compensation									21,000
Stock Options [Member]
Class Of Stock [Line Items]
Cash Recieved For Exercise Of Non Vested Options								100
Restricted Stock
Class Of Stock [Line Items]
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount								$ 14,100
Restricted Stock Units (RSUs) [Member]
Class Of Stock [Line Items]
Convertible Preferred Stock Issuance Cost									$ 1,600
2021 Stock Incentive Plan
Class Of Stock [Line Items]
Convertible preferred stock								4,600,000
Sale of common stock								50,000,000
Stock option granted maximum term								10 years
Percentage Of Exercise Price To Fair Market Value Common Stock On Grant Date								100%
Increase In Common Stock Shares Reserved For Future Issuance								2,058,885
Percentage Of Common Stock Outstanding								5%
2021 Stock Incentive Plan | Stock Options [Member]
Class Of Stock [Line Items]
Percentage Of Exercise Price To Fair Market Value Common Stock On Grant Date								110%
IPO [Member]
Class Of Stock [Line Items]
Common stock converted		21,634,898		21,634,898
Preferred stock, shares outstanding		89,908,215
Sale of common stock		12,133,333
Employee Stock [Member]
Class Of Stock [Line Items]
Convertible preferred stock								400,000
Sale of common stock								15,000,000
Increase In Common Stock Shares Reserved For Future Issuance								411,777
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount								$ 43,400
Percentage Of Common Stock Outstanding								1%
Number of purchased shares by the employee								71,272	16,606
Stock-based compensation expense related to the ESPP								$ 300	$ 100
Common Stock [Member]
Class Of Stock [Line Items]
Proceeds from issuance of convertible preferred stock, net of issuance costs								9,400
Payments of Debt Issuance Costs								$ 600
Sale of common stock								980,000
Series A-1 Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Convertible preferred stock, shares issued						21,944,874
Series B Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock, shares issued								35,764,462
Preferred stock, par value								$ 0.0001
Proceeds from issuance of convertible preferred stock, net of issuance costs								$ 92,700
Series B-1 Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Convertible, Conversion Price								$ 2.82172
Proceeds From Issuance Of Convertible Preferred Stock Up On Achievement Of Closing Milestone								$ 350
Preferred stock, shares issued								32,958,612
Series B-2 Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Offerings share price			85%
Stock Issued During Period, Shares, Conversion of Convertible Securities			2,805,850
Interest on Convertible Debt, Net of Tax								$ 200
Preferred stock, shares issued								2,805,850
Promissory note and derivative liability conversion into share			2,805,850
Shares issued price per share			$ 2.39846

Convertible Preferred Stock a_4

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Schedule of Common Stock Reserved for Future Issuance (Details)	Dec. 31, 2022 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	12,503,969
Common Stock Options and Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	9,387,963
Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	2,409,593
2021 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	706,413

Convertible Preferred Stock a_5

Convertible Preferred Stock and Stockholders' Equity - Summary of the RSU under Equity incentive plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted	3,112,560
Expected to vest at Dec 31,2022	8,384,990
Weight granted fair value Nonvested Granted	$ 7.33	$ 8.52
Weighted average exercise price per share, Vested and exercisable at Dec 31, 2022	$ 8.06
Service Based RSU Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Nonvested at December 31, 2021	388,500
Granted	906,271
Vested	(278,281)
Forfeited	49,517
Nonvested at December 31, 2022	966,973	388,500
Expected to vest at Dec 31,2022	966,973
Weighted Average Nonvested at December 31, 2021	$ 25.96
Weight granted fair value Nonvested Granted	12.25
Weighted-average grant date fair value, Vested	11.34
Weighted-average grant date fair value, Forfeited	(16.45)
Weighted Average Grant Nonvested at Dec 31, 2022	17.81	$ 25.96
Weighted average exercise price per share, Vested and exercisable at Dec 31, 2022	$ 17.81
Performance Based RSUs Member
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted	60,000
Vested	(24,000)
Nonvested at December 31, 2022	36,000
Weight granted fair value Nonvested Granted	$ 18.74
Weighted-average grant date fair value, Vested	10.91
Weighted Average Grant Nonvested at Dec 31, 2022	$ 3.08

Convertible Preferred Stock a_6

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Summary of the Status of the Options Issued Under the Plan (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Stockholders' Equity Note [Abstract]
Balance at December 31, 2021 | shares	6,591,727
Granted | shares	3,112,560
Exercised | shares	(395,050)
Forfeited | shares	377,233
Expired | shares	(547,014)
Balance at December 31, 2022 | shares	8,384,990
Expected to vest at Dec 31,2022 | shares	8,384,990
Options Outstanding, Vested and exercisable at Dec 31, 2022 | shares	2,219,625
Weighted average exercise price per share, Balance at December 31, 2021 | $ / shares	$ 8.04
Granted | $ / shares	9.66
Exercised | $ / shares	1.48
Forfeited | $ / shares	10.91
Expired | $ / shares	5.32
Weighted average exercise price per share, Balance at December 31, 2022 | $ / shares	9
Vested and expected to vest as of December 31, 2022 | $ / shares	9
Weighted average exercise price per share, Vested and exercisable at Dec 31, 2022 | $ / shares	$ 8.06
Weighted average remaining contractual term (Years)	8 years 8 months 19 days
Vested and expected to vest as of December 31, 2022	8 years 8 months 19 days
Vested and exercisable at December 31, 2022	8 years 3 months 21 days
Aggregate intrinsic value, Balance at December 31, 2022 | $	$ 20,499
Vested and expected to vest as of December 31, 2022 | $	20,499
Vested and exercisable at December 31, 2022 | $	$ 5,636

Convertible Preferred Stock a_7

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Schedule of Stock-based Compensation Expense for All Equity Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Stock-based compensation expense related to the ESPP	$ 21,694	$ 29,031
Research and Development Expense [Member]
Class Of Stock [Line Items]
Stock-based compensation expense related to the ESPP	8,123	2,710
General and Administrative [Member]
Class Of Stock [Line Items]
Stock-based compensation expense related to the ESPP	$ 13,571	$ 26,321

Convertible Preferred Stock a_8

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Summary of Assumptions Used in Black-Scholes Model (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Risk-free rate of interest, Minimum	1.43%	0.63%
Risk-free rate of interest, Maximum	4.15%	1.34%
Expected stock price volatility, Minimum	89.30%	84.20%
Expected stock price volatility, Maximum	118.10%	90.90%
Dividend yield	0%	0%
Maximum [Member]
Class Of Stock [Line Items]
Expected term (years)	6 years 29 days	6 years 29 days
Minimum [Member]
Class Of Stock [Line Items]
Expected term (years)	5 years 3 months 7 days	5 years 9 months 7 days

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate and Effective Income Tax Rate (Detail)		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	21%	21%
State income taxes, net of federal tax	1.10%	1%
Other permanent differences	0.40%	(0.40%)
Research and development tax credits	3.40%	3.10%
Research and Development Credit Permanent Adjustment	0%	(0.60%)
Stock-based compensation	(2.20%)	(1.60%)
Uncertain Tax Positions	(0.90%)	(0.80%)
Change in valuation allowance	(22.80%)	(21.70%)
Effective Income Tax Rate Reconciliation, Percent, Total	0%	0%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Liabilities) Included in Other Assets in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 17,304	$ 12,623
Capitalized research and development	11,731	0
Research and development credits	4,599	2,349
Deferred revenue	0	126
Operating lease liabilities	1,951	0
Stock-based compensation	2,203	5,192
Other	712	533
Total deferred tax assets	38,500	20,823
Property and equipment	1,135	0
Right-of-use assets operating leases	(720)	0
Other	(269)	(280)
Total deferred tax liabilities	(2,124)	(280)
Less: valuation allowance	(36,376)	(20,543)
Deferred Tax Assets, Net, Total	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	$ 36,376,000	$ 20,543,000
Increase in valuation allowance	15,800,000
Research and development credits	$ 4,599,000	$ 2,349,000
Federal Operating Loss Carry forwards Expiration Period	2037
State Operating Loss Carry forwards Expiration Period	2035
Deferred tax assets	$ 11,700,000
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 76,200,000
Operating Loss Carry Forwards Expiration Period	2037
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 30,800,000
Operating Loss Carry Forwards Expiration Period	2032
Research and Development Tax Credit Carryforwards | Federal
Operating Loss Carryforwards [Line Items]
Research and development credits	$ 5,900,000
Research and Development Tax Credit Carryforwards | State
Operating Loss Carryforwards [Line Items]
Research and development credits	$ 300

Income Taxes - Summary of Unrec

Income Taxes - Summary of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning of year	$ 758	$ 263
Additions based on tax positions relating to current year	775	495
Unrecognized tax benefits, end of year	$ 1,547	$ 758

Employee Savings Plan - Additio

Employee Savings Plan - Additional Information (Details) - USD ($)		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Employer discretionary contribution amount	$ 100	$ 0
Maximum
Defined Contribution Plan Disclosure [Line Items]
Percent of employees gross pay	90%