0000950170-22-011331 | 10-Q | XBRL Viewer

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2022	May 31, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	HILLEVAX, INC.
Entity Central Index Key	0001888012
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Small Business	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		33,427,209
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity File Number	001-41365
Entity Tax Identification Number	85-0545060
Entity Address Address Line1	75 State Street
Entity Address, Address Line Two	Suite 100 - #9995
Entity Address City Or Town	Boston
Entity Address State Or Province	MA
Entity Address Postal Zip Code	02109
Entity Incorporation State Country Code	DE
City Area Code	617
Local Phone Number	213-5054
Title of each class	Common Stock, $0.0001 par value per share
Trading Symbol	HLVX
Name of each exchange on which registered	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 111,252	$ 124,566
Prepaid expenses and other current assets	480	141
Total current assets	111,732	124,707
Property and equipment, net		42
Operating lease right-of-use assets	176	189
Other assets	2,788	2,221
Total assets	114,696	127,159
Current liabilities:
Accounts payable (includes related party amounts of $1,301 and $22, respectively)	4,010	1,024
Accrued expenses (includes related party amounts of $230 and $4,911, respectively)	4,778	9,164
Accrued interest (includes related party amounts of $1,252 and $723, respectively)	4,885	2,821
Convertible promissory notes payable at fair value (includes related party amounts of $40,580 and $40,580, respectively)	175,349	158,276
Current portion of operating lease liability	35	32
Warrant liabilities - related party	93,869	56,445
Total current liabilities	282,926	227,762
Operating lease liability, net of current portion	141	153
Other long-term liabilities	1	1
Total liabilities	283,068	227,916
Commitments and contingencies (Note 3)
Stockholders’ deficit:
Common stock, $0.0001 par value; authorized shares 50,000,000 at March 31, 2022 and December 31, 2021; issued shares—9,225,321 at March 31, 2022 and December 31, 2021, respectively; outstanding shares—6,897,450 and 6,599,886 at March 31, 2022 and December 31, 2021, respectively	1	1
Additional paid-in capital	4,698	4,426
Accumulated deficit	(173,071)	(105,184)
Total stockholders’ deficit	(168,372)	(100,757)
Total liabilities and stockholders’ deficit	$ 114,696	$ 127,159

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Common stock par value	$ 0.0001	$ 0.0001
Common stock shares authorized	50,000,000	50,000,000
Common stock shares issued	9,225,321	9,225,321
Common stock shares outstanding	6,897,450	6,599,886
Accounts Payable
Related party amounts	$ 1,301	$ 22
Accrued Expenses
Related party amounts	230	4,911
Accrued Interest
Related party amounts	1,252	723
Convertible Promissory Notes Payable
Related party amounts	$ 44,958	$ 40,580

- Definition

Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

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Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development (includes related party amounts of $1,422 and $15, respectively)	$ 6,211	$ 267
In-process research and development	2,500
General and administrative (includes related party amounts of $26 and $165, respectively)	2,603	1,198
Operating Expenses, Total	11,314	1,465
Operating Income (Loss), Total	(11,314)	(1,465)
Other income (expense):
Interest income	6
Interest expense (includes related party amounts of $529 and $8, respectively)	(2,064)	(9)
Change in fair value of convertible promissory notes (includes related party amounts of $4,378 and $73, respectively)	(17,073)	(73)
Change in fair value of warrant liabilities - related party	37,424
Other income (expense)	(18)	1
Total other income (expense)	(56,573)	(81)
Net loss	$ (67,887)	$ (1,546)
Net loss per share, basic	$ (10.06)	$ (0.32)
Net loss per share, diluted	$ (10.06)	$ (0.32)
Weighted-average shares of common stock outstanding, basic	6,748,668	4,802,907
Weighted-average shares of common stock outstanding, diluted	6,748,668	4,802,907

Condensed Consolidated Statements of Operations (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Related party expenses	$ 1,422	$ 15
General and administrative, related party	26	165
Interest expense, related party	529	9
Change in fair value of convertible promissory notes, related party	$ 4,378	$ 73

- Definition

Direct costs arising from transactions with related parties who are not affiliates or joint Ventures. These costs are categorized as cost of goods sold.

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Condensed Consolidated Statements of Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2020	$ (2,773)		$ 3	$ (2,776)
Beginning Balance, Shares at Dec. 31, 2020		4,759,968
Issuance of common stock, Shares		1,606,815
Vesting restrictions placed on previously issued and outstanding common stock	(1)		(1)
Vesting restrictions placed on previously issued and outstanding common stock, Shares		(2,332,386)
Vesting of restricted shares, Shares		826,052
Net loss	(1,546)			(1,546)
Ending Balance at Mar. 31, 2021	(4,320)		2	(4,322)
Ending Balance, Shares at Mar. 31, 2021		4,860,449
Beginning Balance at Dec. 31, 2021	(100,757)	$ 1	4,426	(105,184)
Beginning Balance, Shares at Dec. 31, 2021		6,599,886
Vesting of restricted shares, Shares		297,564
Stock - based compensation	272		272
Net loss	(67,887)			(67,887)
Ending Balance at Mar. 31, 2022	$ (168,372)	$ 1	$ 4,698	$ (173,071)
Ending Balance, Shares at Mar. 31, 2022		6,897,450

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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+ Details

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (67,887)	$ (1,546)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	272
Change in fair value of convertible promissory notes (includes related party amounts of $4,378 and $73, respectively)	17,073	73
Change in fair value of warrant liabilities - related party	37,424
Acquired in-process research and development	2,500
Loss on disposal of property and equipment	42
Changes in operating assets and liabilities:
Prepaid expenses and other current assets (includes related party amounts of $0 and $12, respectively)	(339)	10
Accounts payable and accrued expenses (includes related party amounts of $(3,402) and $67, respectively)	(1,868)	1,037
Accrued interest (includes related party amounts of $529 and $9, respectively)	2,064	9
Operating lease right-of-use assets and liabilities	4
Net cash used in operating activities	(10,715)	(417)
Cash flows from investing activities
Cash paid for purchased in-process research and development	(2,500)
Net cash used in investing activities	(2,500)
Cash flows from financing activities
Payment of initial public offering costs	(99)
Net cash used in financing activities	(99)
Net decrease in cash and cash equivalents	(13,314)	(417)
Cash and cash equivalents—beginning of period	124,566	457
Cash and cash equivalents—end of period	111,252	$ 40
Supplemental disclosure of noncash investing and financing activities
Unpaid initial public offering costs	$ 548

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement Of Cash Flows [Abstract]
Change in fair value of convertible promissory notes, related party	$ 4,378	$ 73
Related parties prepaid expenses and other assets current	0	12
Related parties accounts payable and accrued expenses	(3,402)	67
Related parties accrued interest	$ 529	$ 9

Organization, Basis of Presentation and Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization, Basis of Presentation and Summary of Significant Accounting Policies

1. Organization, Basis of Presentation and Summary of Significant Accounting Policies

Organization

HilleVax, Inc. (the “Company” or “HilleVax”) was incorporated in the state of Delaware in March 2020 under the name MokshaCo, Inc. (“MokshaCo”). On February 8, 2021, MokshaCo changed its name to HilleVax and merged with North Bridge V, Inc. (“North Bridge V”) and YamadaCo III, Inc. (“YamadaCo III”), each a Delaware corporation formed in 2019, with HilleVax being the surviving entity (the “Merger”). The Company is a biopharmaceutical company focused on developing and commercializing novel vaccines.

Forward Stock Split

On April 22, 2022, the Company effected a 1.681-for-1 forward split of shares of the Company’s common stock (the “Forward Stock Split”). The par value of the common stock was not adjusted as a result of the Forward Stock Split and the authorized shares were increased to 50,000,000 shares of common stock in connection with the Forward Stock Split. The accompanying financial statements and notes to the financial statements give retroactive effect to the Forward Stock Split for all periods presented, unless otherwise indicated.

Basis of Presentation

The Company, North Bridge V and YamadaCo III were entities under the common control of Frazier Life Sciences X, L.P. or its affiliates (“Frazier”) as a result of, among others, Frazier’s; (i) ownership of a majority of the outstanding capital stock of each of the companies, (ii) financing of each of the companies, (iii) control of board of directors of each of the companies, and (iv) management of each of the companies. As the merged entities were under common control, the financial statements prior to the Merger report the financial position, results of operations and cash flows of these merged companies. The financial statements also include, subsequent to its formation in May 2021, the accounts of HilleVax GmbH, a wholly-owned subsidiary formed in Zurich, Switzerland. The functional currency of both the Company and HilleVax GmbH is the U.S. dollar. The Company’s assets and liabilities that are not denominated in the functional currency are remeasured into U.S. dollars at foreign currency exchange rates in effect at the balance sheet date except for nonmonetary assets, which are remeasured at historical foreign currency exchange rates in effect at the date of transaction. Net realized and unrealized gains and losses from foreign currency transactions and remeasurement are reported in other income (expense), in the condensed consolidated statements of operations and were not material for the periods presented. All intercompany transactions have been eliminated in consolidation.

Liquidity and Capital Resources

From inception to March 31, 2022, the Company has devoted substantially all of its efforts to organizing and staffing the Company, business planning, raising capital, in-licensing its initial vaccine candidate, HIL-214, preparing for its planned clinical trials of HIL-214, and providing other general and administrative support for these operations. The Company has a limited operating history, has never generated any revenue, 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 and potential commercialization of HIL-214. From inception to March 31, 2022, the Company has funded its operations through the issuance of convertible promissory notes.

The accompanying condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. Management is required to perform a two-step analysis over the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management believes that it has sufficient working capital on hand, including the net proceeds from the Company’s initial public offering ("IPO") in May 2022 (see Note 6), to fund operations through at least the next twelve months from the date these financial statements were issued. There can be no assurance that the Company will be successful in acquiring additional funding, if needed,

that the Company’s projections of its future working capital needs will prove accurate, or that any additional funding would be sufficient to continue operations in future years.

Unaudited Interim Financial Information

The unaudited condensed consolidated financial statements as of March 31, 2022, and for the three months ended March 31, 2022 and 2021, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”), and with U.S. generally accepted accounting principles (“GAAP”) applicable to interim financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s audited financial statements and include all adjustments, consisting of only normal recurring accruals, which in the opinion of management are necessary to present fairly the Company’s financial position as of the interim date and results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year or future periods. The condensed consolidated balance sheet data as of December 31, 2021 was derived from the Company’s audited financial statements but does not include all disclosures required by GAAP. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2021, included in the Company’s prospectus filed with the SEC on April 29, 2022 pursuant to Rule 424(b) under the Securities Act of 1933, as amended.

Use of Estimates

The preparation of the Company’s unaudited condensed consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the Company’s condensed consolidated financial statements and accompanying notes. The most significant estimates in the Company’s unaudited condensed consolidated financial statements relate to accruals for research and development expenses, and the valuation of convertible promissory notes, warrant liabilities and various other equity instruments. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results could differ materially from those estimates and assumptions.

Fair Value Option

As permitted under Accounting Standards Codification (“ASC”) 825, Financial Instruments, (“ASC 825”), the Company has elected the fair value option to account for its convertible promissory notes issued through December 31, 2021. In accordance with ASC 825, the Company records these convertible promissory notes at fair value with changes in fair value recorded in the condensed consolidated statements of operations. As a result of applying the fair value option, direct costs and fees related to the convertible promissory notes were recognized in earnings as incurred and not deferred.

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 non-recurring 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: Observable inputs such as quoted prices in active markets.

Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The carrying amounts of the Company’s financial instruments, including cash and cash equivalents classified within the Level 1 designation discussed above, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. Warrant liabilities and convertible notes are recorded at fair value on a recurring basis.

The Company has no financial assets measured at fair value on a recurring basis. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

Liabilities measured at fair value on a recurring basis are as follows (in thousands):


			Fair Value Measurements at Reporting Date Using:
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of March 31, 2022:
Warrant liabilities	$	93,869	$	—	$	—	$	93,869
Convertible promissory notes		175,349		—		—		175,349
Total	$	269,218	$	—	$	—	$	269,218
As of December 31, 2021:
Warrant liabilities	$	56,445	$	—	$	—	$	56,445
Convertible promissory notes		158,276		—		—		158,276
Total	$	214,721	$	—	$	—	$	214,721

The warrant liabilities consist of an issued and outstanding common stock warrant (the “Takeda Warrant”) and a right to receive an additional common stock warrant (the “Takeda Warrant Right”, and together with the Takeda Warrant, the “Takeda Warrants”) issued to Takeda Vaccines, Inc. (“Takeda”) in connection with a July 2021 license agreement. The Takeda Warrants are accounted for as liabilities as they do not meet all the conditions for equity classification due to (i) insufficient authorized shares for the Takeda Warrant and (ii) the Takeda Warrant Right is not indexed to the Company’s own stock. The fair value of the Takeda Warrants is derived from the model used to estimate the fair value of the Company’s common stock (see Note 5).

The Company issued convertible promissory notes to Frazier (the “Frazier Notes”) from April 2019 to July 2021 and issued unsecured convertible promissory notes in August 2021 (the “August 2021 Notes”) to investors including Frazier. The Company has elected the fair value option for each of its convertible promissory note issuances due to certain embedded features within the notes. The fair value of the Frazier Notes and the August 2021 Notes was estimated using a scenario-based analysis that estimated the fair value of the convertible promissory notes based on the probability-weighted present value of expected future investment returns, considering possible outcomes available to the noteholders, including various IPO, settlement, equity financing, corporate transactions and dissolution scenarios. The Frazier Notes were exchanged for August 2021 Notes in August 2021.

The Company adjusts the carrying value of its warrant liabilities and convertible promissory notes to their estimated fair value at each reporting date, with any related increases or decreases in the fair value recorded as change in fair value of warrant liabilities and as change in fair value of convertible promissory notes, respectively, in the condensed consolidated statements of operations.

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of March 31, 2022:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$9.66 - $18.62
	Estimated time to liquidity	0.12 - 1.50 years
	Discount rate	18%
August 2021 Notes	Estimated time to liquidity	0.12 - 1.50 years
	Volatility	79% - 110%
	Discount rate	16% - 18%
	Risk-free interest rate	0.2% - 2.0%

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of December 31, 2021:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$11.83 - $12.54
	Estimated time to liquidity	0.20 - 1.75 years
	Discount rate	20%
August 2021 Notes	Estimated time to liquidity	0.20 - 1.75 years
	Volatility	80% - 100%
	Discount rate	19% - 20%
	Risk-free interest rate	0.1% - 0.7%

There are significant judgments, assumptions and estimates inherent in the determination of the fair value of each of the instruments described above. These include determination of a valuation method and selection of the possible outcomes available to the Company, including the determination of timing and expected future investment returns for such scenarios. The related judgments, assumptions and estimates are highly interrelated and changes in any one assumption could necessitate changes in another. In particular, any changes in the probability of a particular outcome would require a related change to the probability of another outcome. In the future, depending on the valuation approaches used and the expected timing and weighting of each, the inputs described above, or other inputs, may have a greater or lesser impact on the Company’s estimates of fair value.

The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs (in thousands):


	Warrant Liabilities		Convertible Promissory Notes
Balance at December 31, 2021	$	56,445	$	158,276
Change in fair value		37,424		17,073
Balance at March 31, 2022	$	93,869	$	175,349

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking accounts and money market funds.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.

Property and Equipment, Net

Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets (generally 3 years). Repairs and maintenance costs are charged to expense as incurred.

Deferred Offering Costs

The Company has deferred offering costs consisting of legal, accounting and other fees and costs directly attributable to its planned IPO. The deferred offering costs will be offset against the proceeds received upon the completion of the planned IPO. As of March 31, 2022 and December 31, 2021, respectively, $2.8 million and $2.2 million of deferred offering costs were recorded within other assets on the condensed consolidated balance sheets.

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. Lease terms are determined at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. For its long-term operating leases, the Company recognizes a lease liability and a right-of-use (“ROU”) asset on its balance sheet and recognizes lease expense on a straight-line basis over the lease term. The lease liability is determined as the present value of future lease payments using the discount rate implicit in the lease or, if the implicit rate is not readily determinable, an estimate of the Company’s incremental borrowing rate. The ROU asset is based on the lease liability, adjusted for any prepaid or deferred rent. The Company aggregates all lease and non-lease components for each class of underlying assets into a single lease component and variable charges for common area maintenance and other variable costs are recognized as expense as incurred. The Company has elected to not recognize a lease liability or ROU asset in connection with short-term operating leases and recognizes lease expense for short-term operating leases on a straight-line basis over the lease term. The Company does not have any financing leases.

Impairment of Long-Lived Assets

The Company reviews long-lived assets, such as property and equipment, for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets. Fair value would be assessed using discounted cash flows or other appropriate measures of fair value. The Company has not recognized any impairment losses through March 31, 2022.

Research and Development Expenses and Accruals

All research and development costs are expensed in the period incurred and consist primarily of salaries, payroll taxes, employee benefits, stock-based compensation charges for those individuals involved in research and development efforts, external research and development costs incurred under agreements with contract research organizations and consultants to conduct and support the Company’s planned clinical trials of HIL-214.

The Company has entered into various research and development contracts with clinical research organizations, clinical manufacturing organizations and other companies. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and payments made in advance of performance are reflected in the accompanying balance sheets as prepaid expenses. The Company records accruals for estimated costs incurred for ongoing research and development activities. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the prepaid or accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates.

In-Process Research and Development

The Company evaluates whether acquired intangible assets are a business under applicable accounting standards. Additionally, the Company evaluates whether the acquired assets have a future alternative use. Intangible assets that do not have future alternative use are considered acquired in-process research and development. When the acquired in-process research and development assets are not part of a business combination, the value of the consideration paid is expensed on the acquisition date.

Patent Costs

Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain.

Stock-Based Compensation

Stock-based compensation expense represents the cost of the grant date fair value of equity awards recognized over the requisite service period of the awards (generally the vesting period) on a straight-line basis. The Company recognizes forfeitures as they occur.

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 the condensed consolidated statements of operations in the period that includes the enactment date.

The Company recognizes net 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 net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

The Company records uncertain tax positions on the basis of a two-step process whereby (i) 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 (ii) 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 in the condensed consolidated statements of operations. Any accrued interest and penalties are included within the related tax liability in the condensed consolidated balance sheets. The Company did not recognize any interest or penalties during the periods presented.

Comprehensive Loss

Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. The Company’s comprehensive loss was the same as its reported net loss for all periods presented.

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker in making decisions on how to allocate resources and assess performance. The Company views its operations and manages its business as one operating segment.

Net Loss Per Share

Basic net loss per share is computed by dividing the consolidated net loss by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. The Company has excluded weighted-average unvested shares of 2,476,653 shares and 1,663,801 shares, respectively, from the weighted-average number of common shares outstanding for the three months ended March 31, 2022 and 2021. Diluted net loss per share is computed by dividing the consolidated net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Potentially dilutive common stock equivalents are comprised of unvested common stock, common stock options, common stock warrants and convertible promissory notes. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the unvested common stock, common stock options, common stock warrants and convertible debt would be antidilutive.

Emerging Growth Company Status

The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has irrevocably elected to avail itself of this exemption from new or revised accounting standards and, therefore, will not be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

Recently Adopted Accounting Standards

There were no recently adopted accounting standards which would have a material impact on the Company's financial statements.

Recently Issued Accounting Pronouncements

The Company assesses the adoption impacts of recently issued accounting standards by the Financial Accounting Standards Board or other standard setting bodies on the Company's condensed consolidated financial statements as well as material updates to previous assessments, if any. There were no new material accounting standards issued in the first quarter of 2022 that impacted the Company.

Related Party Transactions

3 Months Ended

Mar. 31, 2022

Related Party Transactions

2. Related Party Transactions

Frazier is a principal stockholder of the Company and is represented on the Company’s board of directors. From January 8, 2019 (inception) to March 31, 2022, the Company and Frazier reimbursed each other for various goods and services, including personnel related expenses, travel, insurance, facilities and other various overhead and administrative expenses. As of March 31, 2022 and December 31, 2021, the Company had outstanding amounts due to Frazier of $0 and $22,000, respectively, related to these shared operating expenses. For the three months ended March 31, 2022 and 2021, the Company incurred $26,000 and $0.2 million, respectively, of shared operating expenses.

Mountain Field LLC (“Mountain Field”) is an entity owned by a former member of the Company’s board of directors. From January 8, 2019 (inception) to March 31, 2022, the Company charged Mountain Field for various personnel related and other administrative expenses associated with the operations of Mountain Field. These shared expenses were allocated based on time incurred by personnel. For the three months ended March 31, 2022 and 2021, the Company charged Mountain Field $0 and $5,000, respectively, for shared expenses.

On July 2, 2021, the Company entered into a license agreement with Takeda pursuant to which it was granted an exclusive sublicensable, royalty-bearing license (the “Takeda License”) to commercialize HIL-214 pharmaceutical products for all human uses on a worldwide basis outside of Japan. In connection with the Takeda License, Takeda became a related party stockholder with representation on the Company’s board of directors. In March 2022, the Company paid Takeda an aggregate $2.5 million contingent payment upon the release of certain drug products and the completion of certain regulatory activities, which have no alternative future use, and was recorded as in-process research and development in the Company’s condensed consolidated statement of operations for the three months ended March 31, 2022.

The Company and Takeda are party to a Transitional Services Agreement (“TSA”) under which the Company is obligated to pay Takeda for certain services, including pass-through costs, related to research and development and regulatory assistance services, oversight and management of ongoing clinical and research studies, and maintenance of third party vendor contracts. For the three months ended March 31, 2022, the Company incurred $1.4 million of research and development expenses for Takeda’s services. As of March 31, 2022, the Company had $1.3 million and $0.2 million, respectively, of accounts payable and accrued expenses due to Takeda. As of December 31, 2021, the Company had $4.9 million of accrued expenses due to Takeda.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

3. Commitments and Contingencies

Operating Lease

In August 2021, the Company entered into a five-year noncancelable operating lease for a facility in Switzerland, which it determined was an operating lease at the inception of the lease contract. The lease commencement date occurred in September 2021 when the Company gained access to the facility. The Company is obligated to make monthly rental payments that periodically escalate during the lease term and is subject to additional charges for common area maintenance and other costs. The Company has an option to extend the lease for a period of five years which the Company is not reasonably certain to exercise.

As of March 31, 2022, the remaining lease term of the Company’s operating lease was 54 months, and the discount rate on the Company’s operating lease was 6.0%. As there was not an implicit rate within the lease, the discount rate was determined by using a set of peer companies incremental borrowing rates. For the three months ended March 31, 2022, operating lease expense and cash paid for amounts included in the measurement of lease liabilities were immaterial.

Future minimum noncancelable operating lease payments, which commenced in October 2021, are as follows (in thousands):


	March 31, 2022
Years ending December 31:
2022 (remaining 9 months)	$	33
2023		44
2024		44
2025		44
2026		35
Total undiscounted operating lease payments		200
Present value adjustment		(24	)
Operating lease liability		176
Less current portion of operating lease liability		35
Operating lease liability, net of current portion	$	141

In March 2022, the Company entered into a lease for office and laboratory space located in Boston, Massachusetts (the “Boston Lease”). The initial lease term is 10 years commencing upon the earlier of (i) nine months following the date the Company gains possession of the premises to commence construction of certain tenant improvements and (ii) the date certain tenant improvements are substantially completed. As of March 31, 2022, the Boston Lease had not yet commenced. Escalating base rental payments and additional charges for operating expenses and management fees are due on a monthly basis. The Boston Lease includes certain tenant improvement allowances, an option for the Company to extend the lease for a period of five years and requires a security deposit of $1.6 million. The future noncancelable lease payments related to the Boston Lease, excluding operating expenses and management fees, total $37.4 million.

Contingencies

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.

Convertible Promissory Notes

3 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

Convertible Promissory Notes

4. Convertible Promissory Notes

Frazier Convertible Note Financings

During 2019, 2020 and 2021, the Company issued the Frazier Notes for an aggregate of $8.5 million bearing interest at per annum rates ranging from 0.12% to 2.52%. An aggregate of $0.9 million of the Frazier Notes were issued in April, May and September of 2019 (the “2019 Frazier Notes”), an aggregate of $1.3 million of the Frazier Notes were issued in March, August and October of 2020 (the “2020 Frazier Notes”) and an aggregate of $6.3 million of Frazier Notes were issued from April to July 2021 (the “2021 Frazier Notes”). The Frazier Notes were generally scheduled to mature 12 to 18 months from the date of issuance. The Company recorded changes in the fair value of the Frazier Notes in the condensed consolidated statements of operations. The Frazier Notes were exchanged for convertible promissory notes newly issued in connection with the August 2021 convertible note financing described below. For the three months ended March 31, 2021, the Company recognized a $0.1 million change in fair value of convertible promissory notes and recognized $9,000 of interest expense in connection with outstanding Frazier Notes.

August 2021 Convertible Note Financing

On August 31, 2021, the Company entered into a note purchase agreement under which it issued the August 2021 Notes for an aggregate of $139.52 million. Of the August 2021 Notes, $103.75 million were issued to new investors, $25.0 million were issued to Frazier for cash and $10.77 million were issued to Frazier in exchange for the then outstanding principal and accrued interest on the Frazier Notes. The August 2021 Notes bear interest at a rate of 6% per annum, compounded annually. For the three months ended March 31, 2022, the Company recognized a $17.1 million change in fair value of convertible promissory notes in the condensed consolidated statements of operations and recognized $2.1 million of interest expense in connection with outstanding August 2021 Notes. As of March 31, 2022 and December 31, 2021, the outstanding principal balance of the August 2021 Notes was $139.5 million.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI https://asc.fasb.org/topic&trid=2208564

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+ Details

Stockholders' Deficit

3 Months Ended

Mar. 31, 2022

Stockholders Equity Note [Abstract]

Stockholders' Deficit

5. Stockholders’ Deficit

A summary of the Company’s unvested shares is as follows:


	Number of Unvested Shares
Balance at December 31, 2021		2,625,435
Share vesting		(297,564	)
Balance at March 31, 2022		2,327,871

For accounting purposes, unvested shares of common stock are considered issued, but not outstanding until they vest. As of March 31, 2022 and December 31, 2021, the Company had no material repurchase liability related to the unvested shares in the table above.

2021 Equity Incentive Plan

On February 8, 2021, the Company’s board of directors and stockholders approved and adopted the HilleVax, Inc. 2021 Equity Incentive Plan (the “2021 Plan”). The term of the 2021 Plan is ten years from the adoption date. Under the 2021 Plan, the Company may grant stock options, restricted stock, restricted stock units, and other stock-based awards to employees, directors or consultants of the Company and its subsidiaries. The stock options granted under the plan generally vest over a four-year period from the vesting commencement date. As of March 31, 2022 a total of 2,969,486 shares were reserved for issuance under the 2021 Plan.

Valuation of Common Stock and Stock-Based Compensation Expense

Prior to obtaining the Takeda License on July 2, 2021, the fair value of the Company’s common stock was nominal since the Company was not sufficiently capitalized and held no assets that could be used to generate future revenues. Subsequent to obtaining the Takeda License, the Company estimated the fair value of its common stock using methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants Accounting and Valuation Guide: Valuation of Privately Held Company Equity Securities Issued as Compensation (the “Practice Aid”). The Practice Aid prescribes several valuation approaches for setting the value of an enterprise, such as the cost, income and market approaches, and various methodologies for allocating the value of an enterprise to its common stock. The Company’s 2021 and 2022 valuations utilized a scenario-based analysis that estimated the fair value per share based on the probability-weighted present value of expected future investment returns, considering each of the possible outcomes available to the Company, including various IPO, stay private and dissolution scenarios, and applying a discount for lack of marketability for certain equity holders. The Company considered various stay private scenarios using the income approach and allocated the indicated equity value, adjusted for the expected impact of the convertible notes, to each class of equity on a fully-diluted basis, considering option value for certain option classes. The Company also considered various IPO scenarios based on expected equity values in an IPO and allocated the indicated equity value to each class of equity on a fully-diluted basis considering the dilutive impacts of the convertible notes.

Since all restricted stock awards from inception were issued prior to obtaining the Takeda License on July 2, 2021, the Company has recorded no material stock-based compensation expense and has no material unrecognized stock-based compensation related to these awards.

A summary of the Company’s stock option activity under the 2021 Plan is as follows (in thousands, except share and per share data):


	Number of Outstanding Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance at December 31, 2021		727,873		$	6.99		9.94	$	765
Granted		479,085			8.05
Cancelled		(16,810	)		6.99
Balance at March 31, 2022		1,190,148		$	7.42		9.80	$	7,907
Vested and expected to vest at March 31, 2022		1,190,148		$	7.42	9.80		$	7,907
Exercisable at March 31, 2022		—		$	—		—	$	—

Stock-Based Compensation Expense

The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:


	Three Months Ended March 31,
	2022	2021 (1)
Risk-free interest rate	1.9%–2.5%	— %
Expected volatility	88.1%–89.5%	— %
Expected term (in years)	5.5–6.1	—
Expected dividend yield	0 %	0 %

(1)

No stock options were granted until December 2021.

Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of grant for zero coupon U.S. Treasury notes with maturities similar to the expected term of the awards.

Expected volatility. Since the Company is not yet a public company and does not have a trading history for its common stock, the expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the biotechnology industry. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

Expected term. The expected term represents the period of time that options are expected to be outstanding. Because the Company does not have historical exercise behavior, it determines the expected life assumption using the simplified method, for employees, which is an average of the contractual term of the option and its vesting period.

Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present intention to pay cash dividends and, therefore, used an expected dividend yield of zero.

Stock-based compensation expense has been reported in the condensed consolidated statements of operations as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Research and development	$	201	$	—
General and administrative		71		—
Total	$	272	$	—

The weighted average grant date fair value per share of option grants for the three months ended March 31, 2022 was $5.92. There were no option grants during the three months ended March 31, 2021. No stock options were exercised during the three months ended March 31, 2022 or 2021. As of March 31, 2022, total unrecognized stock-based compensation cost was approximately $6.0 million, which is expected to be recognized over a remaining weighted-average period of approximately 3.75 years.

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following:


	March 31, 2022
Common stock warrants		5,883,500
Common stock options outstanding		1,190,148
Shares available for issuance under the 2021 Plan		216,849
		7,290,497

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Subsequent Events

3 Months Ended

Mar. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

6. Subsequent Events

Term Loan Facility

On April 18, 2022, the Company entered into a Loan and Security Agreement (“Loan Agreement”) with Hercules Capital, Inc. (“Hercules”), as administrative and collateral agent, and the lenders party thereto¸ providing for term loans (“Term Loans”) of up to $75.0 million in the aggregate. The Company borrowed $5.0 million on April 18, 2022 and has the right to borrow up to an additional $10.0 million through December 15, 2022 and up to an additional $15.0 million through June 30, 2023 (collectively, “Term Loan 1”). The Company also has the right to borrow up to $20.0 million through June 30, 2023 (“Term Loan 2”). In addition, the Company has the right to borrow $25.0 million through March 31, 2024 (“Term Loan 3”), provided that on or prior to March 31, 2023, (i) the Company has announced that the planned Phase 2b clinical trial evaluating the safety, immunogenicity, and efficacy of HIL-214 in infants (“HIL-214 Vaccine Trial”) will continue without material adverse modification after completion of the planned interim safety and immunogenicity analysis on the first 200 evaluable subjects in the HIL-214 Vaccine Trial, and (ii) the Company has announced the completion of subject enrollment for the HIL-214 Vaccine Trial, which shall involve the enrollment of approximately 3,000 or more subjects. All Term Loans are subject to a minimum draw amount of $5.0 million and no event of default under the Loan Agreement having occurred and is continuing. The borrowings under the Loan Agreement are collateralized by substantially all of the Company’s assets, including intellectual property and certain other assets.

The Term Loans bear (a) cash interest at a floating rate of the higher of (i) the Wall Street Journal prime rate (or 5.00% if less) plus 1.05%, or (ii) 4.55%, and (b) additional interest at a per annum rate equal to 2.85%, with such interest being added to the outstanding principal balance of the Term Loans on a monthly basis. The monthly payments consist of interest-only through June 1, 2025 or, if prior to April 30, 2025, (x) the conditions to Term Loan 3 have been satisfied and (y) the Company has reasonably determined that (i) the HIL-214 Vaccine Trial has achieved the protocol-specified primary efficacy endpoint and (ii) HIL-214 has demonstrated acceptable safety results in the HIL-214 Vaccine Trial, and, as a result, the Company supports the initiation of a Phase 3 registrational trial as the next immediate step in the development of HIL-214, in each case subject to reasonable verification by Hercules, through June 1, 2026. Subsequent to the interest-only period, the Term Loans will be payable in equal monthly installments of principal, plus accrued and unpaid interest, through the maturity date of May 1, 2027. In addition, the Company is obligated to pay a final payment fee equal to the greater of (i) $2.1 million and (ii) 7.15% of the original principal amount of the Term Loans. The Company may elect to prepay all or a portion of the Term Loans prior to maturity, subject to a prepayment fee of up to 2.00% of the then outstanding principal balance and the pro rata application of such payment to the final payment fee. After repayment, no Term Loan amounts may be borrowed again.

The Loan Agreement contains certain customary affirmative and negative covenants and events of default. The affirmative covenants include, among others, covenants requiring the Company to maintain its legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding its operating accounts. The negative covenants include, among others, limitations on the Company’s ability to incur additional indebtedness and liens, merge with other companies or consummate certain changes of control, acquire other companies or businesses, make certain investments, pay dividends, transfer or dispose of assets, amend certain material agreements, including the Takeda License, or enter into various specified transactions. Upon the occurrence of an event of default, subject to any specified cure periods, all amounts owed by the Company would begin to bear interest at a rate that is 4.00% above the rate effective immediately before the event of default and may be declared immediately due and payable by Hercules, as collateral agent.

2022 Incentive Award Plan

In April 2022, the Company’s board of directors and stockholders approved the 2022 Incentive Award Plan (the “2022 Plan”) under which the Company may grant stock options, restricted stock, dividend equivalents, restricted stock units, stock appreciation rights, and other stock or cash-based awards to its employees, consultants and directors. The 2022 Plan became effective in connection with the Company’s IPO and will remain in effect until the tenth anniversary of its effective date, which will be April 28, 2032, unless earlier terminated by the Company’s board of directors. The number of shares of the Company's common stock initially available for issuance under awards granted pursuant to the 2022 Plan was the sum of (1) 4,900,000 shares of the Company’s common stock, plus (2) any shares remaining available for issuance under the 2021 Plan as of the effective date of the 2022 Plan, plus (3) any shares subject to outstanding awards under the 2021 Plan as of the effective date of the 2022 Plan that become available for issuance under the 2022 Plan thereafter in accordance with its terms. The number of shares initially available for issuance will be increased by an annual increase on January 1 of each calendar year beginning in 2023 and ending in and including 2032, equal to the lesser of (1) 5% of the shares of common stock outstanding on the final day of the immediately preceding calendar year and (2) such smaller number of shares as determined by the Company’s board of directors. In connection with the Company’s IPO, the Company’s board of directors approved the grant under the 2022 Plan of stock options to purchase

an aggregate of 132,799 shares of its common stock to certain of the Company’s employees, at an exercise price equal to the IPO price.

2022 Employee Stock Purchase Plan

In April 2022, the Company’s board of directors and stockholders approved the 2022 Employee Stock Purchase Plan (the “2022 ESPP”). The 2022 ESPP became effective in connection with the Company’s IPO. The 2022 ESPP permits eligible employees who elect to participate in an offering under the ESPP to have up to a specified percentage of their eligible earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the 2022 ESPP. The price of common stock purchased under the 2022 ESPP is equal to 85% of the lower of the fair market value of the common stock on the first trading day of the offering period or the relevant purchase date. A total of 410,000 shares of the Company’s common stock was initially reserved for issuance under the 2022 ESPP. In addition, the number of shares available for issuance under the 2022 ESPP will be annually increased on January 1 of each calendar year beginning in 2023 and ending in and including 2032, by an amount equal to the lesser of (1) 1% of the shares outstanding on the final day of the immediately preceding calendar year and (2) such smaller number of shares as is determined by the Company’s board of directors, provided that no more than 10,000,000 shares of the Company’s common stock may be issued under the 2022 ESPP.

Initial Public Offering

On May 3, 2022, the Company completed its IPO whereby it sold 13,529,750 shares of common stock at a public offering price of $17.00 per share, for net proceeds of approximately $210.3 million, after deducting underwriting discounts, commissions and offering costs of approximately $19.7 million. In addition, each of the following occurred in connection with the Company's IPO (i) the issuance of 10,672,138 shares of common stock upon the automatic conversion of August 2021 Notes, (ii) the expiration of the right granted to Takeda to receive an additional common stock warrant, (iii) the reclassification of the Takeda Warrant and August 2021 Notes to stockholders’ equity at their fair values, and (iv) an increase in the number of authorized shares of the Company's common stock and preferred stock to 500,000,000 shares and 50,000,000 shares, respectively.

Organization, Basis of Presentation and Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Forward Stock Split

Basis of Presentation

Liquidity and Capital Resources

that the Company’s projections of its future working capital needs will prove accurate, or that any additional funding would be sufficient to continue operations in future years.

Unaudited Interim Financial Information

Use of Estimates

Fair Value Option

Fair Value Measurements

Level 1: Observable inputs such as quoted prices in active markets.

Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

Liabilities measured at fair value on a recurring basis are as follows (in thousands):


			Fair Value Measurements at Reporting Date Using:
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of March 31, 2022:
Warrant liabilities	$	93,869	$	—	$	—	$	93,869
Convertible promissory notes		175,349		—		—		175,349
Total	$	269,218	$	—	$	—	$	269,218
As of December 31, 2021:
Warrant liabilities	$	56,445	$	—	$	—	$	56,445
Convertible promissory notes		158,276		—		—		158,276
Total	$	214,721	$	—	$	—	$	214,721

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of March 31, 2022:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$9.66 - $18.62
	Estimated time to liquidity	0.12 - 1.50 years
	Discount rate	18%
August 2021 Notes	Estimated time to liquidity	0.12 - 1.50 years
	Volatility	79% - 110%
	Discount rate	16% - 18%
	Risk-free interest rate	0.2% - 2.0%

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of December 31, 2021:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$11.83 - $12.54
	Estimated time to liquidity	0.20 - 1.75 years
	Discount rate	20%
August 2021 Notes	Estimated time to liquidity	0.20 - 1.75 years
	Volatility	80% - 100%
	Discount rate	19% - 20%
	Risk-free interest rate	0.1% - 0.7%

The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs (in thousands):


	Warrant Liabilities		Convertible Promissory Notes
Balance at December 31, 2021	$	56,445	$	158,276
Change in fair value		37,424		17,073
Balance at March 31, 2022	$	93,869	$	175,349

Cash and Cash Equivalents

Concentrations of Credit Risk

Property and Equipment, Net

Deferred Offering Costs

Leases

Impairment of Long-Lived Assets

Research and Development Expenses and Accruals

In-Process Research and Development

Patent Costs

Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain.

Stock-Based Compensation

Emerging Growth Company Status

Recently Adopted/Issued Accounting Standards/Pronouncements

Recently Adopted Accounting Standards

There were no recently adopted accounting standards which would have a material impact on the Company's financial statements.

Recently Issued Accounting Pronouncements

Organization, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Liabilities Measured at Fair Value on Recurring Basis

Liabilities measured at fair value on a recurring basis are as follows (in thousands):


			Fair Value Measurements at Reporting Date Using:
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of March 31, 2022:
Warrant liabilities	$	93,869	$	—	$	—	$	93,869
Convertible promissory notes		175,349		—		—		175,349
Total	$	269,218	$	—	$	—	$	269,218
As of December 31, 2021:
Warrant liabilities	$	56,445	$	—	$	—	$	56,445
Convertible promissory notes		158,276		—		—		158,276
Total	$	214,721	$	—	$	—	$	214,721

Summary of Significant Unobservable Inputs Used in Fair Value Measurements

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of March 31, 2022:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$9.66 - $18.62
	Estimated time to liquidity	0.12 - 1.50 years
	Discount rate	18%
August 2021 Notes	Estimated time to liquidity	0.12 - 1.50 years
	Volatility	79% - 110%
	Discount rate	16% - 18%
	Risk-free interest rate	0.2% - 2.0%

The following table summarizes information about the significant unobservable inputs used in the fair value measurements for the Takeda Warrants and the August 2021 Notes as of December 31, 2021:


Liability	Key Unobservable Inputs	Range
Takeda Warrants	Transaction prices per share	$11.83 - $12.54
	Estimated time to liquidity	0.20 - 1.75 years
	Discount rate	20%
August 2021 Notes	Estimated time to liquidity	0.20 - 1.75 years
	Volatility	80% - 100%
	Discount rate	19% - 20%
	Risk-free interest rate	0.1% - 0.7%

Reconciliation of All Liabilities Measured at Fair Value Using Level 3 Significant Unobservable Inputs

The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs (in thousands):


	Warrant Liabilities		Convertible Promissory Notes
Balance at December 31, 2021	$	56,445	$	158,276
Change in fair value		37,424		17,073
Balance at March 31, 2022	$	93,869	$	175,349

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Noncancelable Operating Lease Payments

Future minimum noncancelable operating lease payments, which commenced in October 2021, are as follows (in thousands):


	March 31, 2022
Years ending December 31:
2022 (remaining 9 months)	$	33
2023		44
2024		44
2025		44
2026		35
Total undiscounted operating lease payments		200
Present value adjustment		(24	)
Operating lease liability		176
Less current portion of operating lease liability		35
Operating lease liability, net of current portion	$	141

Stockholder's Deficit (Tables)

3 Months Ended

Mar. 31, 2022

Stockholders Equity Note [Abstract]

Summary of Unvested Shares

A summary of the Company’s unvested shares is as follows:


	Number of Unvested Shares
Balance at December 31, 2021		2,625,435
Share vesting		(297,564	)
Balance at March 31, 2022		2,327,871

Summary of Stock Option Activity

A summary of the Company’s stock option activity under the 2021 Plan is as follows (in thousands, except share and per share data):


	Number of Outstanding Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance at December 31, 2021		727,873		$	6.99		9.94	$	765
Granted		479,085			8.05
Cancelled		(16,810	)		6.99
Balance at March 31, 2022		1,190,148		$	7.42		9.80	$	7,907
Vested and expected to vest at March 31, 2022		1,190,148		$	7.42	9.80		$	7,907
Exercisable at March 31, 2022		—		$	—		—	$	—

Summary of Assumptions used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants

The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:


	Three Months Ended March 31,
	2022	2021 (1)
Risk-free interest rate	1.9%–2.5%	— %
Expected volatility	88.1%–89.5%	— %
Expected term (in years)	5.5–6.1	—
Expected dividend yield	0 %	0 %

(1)

No stock options were granted until December 2021.

Schedule of Stock-based Compensation Expense

Stock-based compensation expense has been reported in the condensed consolidated statements of operations as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Research and development	$	201	$	—
General and administrative		71		—
Total	$	272	$	—

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following:


	March 31, 2022
Common stock warrants		5,883,500
Common stock options outstanding		1,190,148
Shares available for issuance under the 2021 Plan		216,849
		7,290,497

Organization, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)		3 Months Ended
	Apr. 22, 2022 shares	Mar. 31, 2022 USD ($) shares	Mar. 31, 2021 shares	Dec. 31, 2021 USD ($) shares
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Common stock shares authorized \| shares		50,000,000		50,000,000
Property and equipment estimated useful life		3 years
Deferred offering costs		$ 2,800,000		$ 2,200,000
Antidilutive securities excluded from computation of earnings per share \| shares		2,476,653	1,663,801
Subsequent Event
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Forward split of shares	1.681
Common stock shares authorized \| shares	50,000,000
Recurring
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Assets measured at fair value		$ 0
Non-Recurring
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Non-financial assets at fair value		0
Non-financial liabilities at fair value		$ 0

Organization, Basis of Presentation and Summary of Significant Accounting Policies - Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	$ 269,218	$ 214,721
Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	93,869	56,445
Convertible Promissory Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	175,349	158,276
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	269,218	214,721
Significant Unobservable Inputs (Level 3) \| Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	93,869	56,445
Significant Unobservable Inputs (Level 3) \| Convertible Promissory Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	$ 175,349	$ 158,276

Organization, Basis of Presentation and Summary of Significant Accounting Policies - Summary of Significant Unobservable Inputs Used in Fair Value Measurements (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2022 $ / shares	Dec. 31, 2021 $ / shares
Takeda Warrants \| Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Warrants measurement input	18	20
Takeda Warrants \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Transaction prices per share	$ 9.66	$ 11.83
Estimated time to liquidity	1 month 13 days	2 months 12 days
Takeda Warrants \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Transaction prices per share	$ 18.62	$ 12.54
Estimated time to liquidity	1 year 6 months	1 year 9 months
August 2021 Notes \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Estimated time to liquidity	1 month 13 days	2 months 12 days
August 2021 Notes \| Minimum \| Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	16	19
August 2021 Notes \| Minimum \| Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	79	80
August 2021 Notes \| Minimum \| Risk-Free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	0.2	0.1
August 2021 Notes \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Estimated time to liquidity	1 year 6 months	1 year 9 months
August 2021 Notes \| Maximum \| Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	18	20
August 2021 Notes \| Maximum \| Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	110	100
August 2021 Notes \| Maximum \| Risk-Free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Notes measurement input	2.0	0.7

Organization, Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation of All Liabilities Measured at Fair Value Using Level 3 Significant Unobservable Inputs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Warrant Liabilities
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2021	$ 56,445
Change in fair value	37,424
Balance at March 31, 2022	93,869
Convertible Promissory Notes
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2021	158,276
Change in fair value	17,073
Balance at March 31, 2022	$ 175,349

Related Party Transactions - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Contingent payment recorded as in-process research and development		$ 2,500,000
Accounts payable	$ 4,010,000	4,010,000		$ 1,024,000
Accrued expenses	4,778,000	4,778,000		9,164,000
Frazier
Related Party Transaction [Line Items]
Due to related parties	0	0		22,000
Shared operating expenses		26,000	$ 200,000
Mountain Field
Related Party Transaction [Line Items]
Shared operating expenses		0	$ 5,000
Takeda
Related Party Transaction [Line Items]
Contingent payment recorded as in-process research and development	2,500,000
Takeda \| TSA
Related Party Transaction [Line Items]
Research and development expenses		1,400,000
Accounts payable	1,300,000	1,300,000
Accrued expenses	$ 200,000	$ 200,000		$ 4,900,000

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Mar. 31, 2022	Aug. 31, 2021	Mar. 31, 2022
Commitments And Contingencies Disclosure [Line Items]
Operating lease, remaining lease term	54 months		54 months
Operating lease, discount rate	6.00%		6.00%
Switzerland
Commitments And Contingencies Disclosure [Line Items]
Operating lease term		5 years
Operating lease, existence of option to extend [true false]		true
Operating lease option to extend			The Company has an option to extend the lease for a period of five years which the Company is not reasonably certain to exercise.
Operating lease renewal term		5 years
Boston, Massachusetts
Commitments And Contingencies Disclosure [Line Items]
Operating lease term	10 years		10 years
Operating lease, existence of option to extend [true false]	true
Operating lease option to extend			an option for the Company to extend the lease for a period of five years
Operating lease renewal term	5 years		5 years
Operating lease security deposit	$ 1.6		$ 1.6
Future noncancelable lease payments excluding operating expenses and management fees			$ 37.4

Commitments and Contingencies - Schedule of Future Minimum Noncancelable Operating Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
2022 (remaining 9 months)	$ 33
2023	44
2024	44
2025	44
2026	35
Total undiscounted operating lease payments	200
Present value adjustment	(24)
Operating lease liability	176
Less current portion of operating lease liability	35	$ 32
Operating lease liability, net of current portion	$ 141	$ 153

Convertible Promissory Notes - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
	Aug. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Convertible Promissory Notes [Line Items]
Change in fair value of convertible promissory notes		$ 17,073	$ 73
Interest expense			$ 9,000
Convertible promissory notes, outstanding principal balance		$ 175,349		$ 158,276
Minimum
Convertible Promissory Notes [Line Items]
Notes issuance, maturity period		12 months
Maximum
Convertible Promissory Notes [Line Items]
Notes issuance, maturity period		18 months
Frazier
Convertible Promissory Notes [Line Items]
Aggregate amount		$ 8,500
Change in fair value of convertible promissory notes		$ 100
Frazier \| Minimum
Convertible Promissory Notes [Line Items]
Bearing interest		0.12%
Frazier \| Maximum
Convertible Promissory Notes [Line Items]
Bearing interest		2.52%
2019 Frazier Notes
Convertible Promissory Notes [Line Items]
Aggregate amount		$ 900
2020 Frazier Notes
Convertible Promissory Notes [Line Items]
Aggregate amount		1,300
2021 Frazier Notes
Convertible Promissory Notes [Line Items]
Aggregate amount		$ 6,300
August 2021 Notes \| Note Purchase Agreement
Convertible Promissory Notes [Line Items]
Aggregate amount	$ 139,520
Debt instrument, interest rate	6.00%
Debt instrument, frequency of periodic payment		annually
Change in fair value of convertible promissory notes		$ 17,100
Interest expense		2,100
Convertible promissory notes, outstanding principal balance		$ 139,500		$ 139,500
August 2021 Notes \| Note Purchase Agreement \| New Investors
Convertible Promissory Notes [Line Items]
Aggregate amount	$ 103,750
August 2021 Notes \| Note Purchase Agreement \| Frazier Life Sciences X, L.P.
Convertible Promissory Notes [Line Items]
Aggregate amount	10,770
Cash proceeds from issuance of convertible notes	$ 25,000

Stockholders' Deficit - Summary of Unvested Shares (Details)	3 Months Ended
	Mar. 31, 2022 shares
Stockholders Equity Note [Abstract]
Number of unvested shares, Beginning balance	2,625,435
Number of unvested shares, Shares vesting	(297,564)
Number of unvested shares, Ending balance	2,327,871

Stockholders' Deficit - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%
Weighted average grant date fair value per share of option grants	$ 5.92
Stock options granted		0	0
Stock options exercised	0	0
Total unrecognized stock-based compensation cost	$ 6.0
Total unrecognized stock-based compensation cost expected to be recognized over remaining weighted-average period	3 years 9 months
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Plan term	ten years
Vesting period	4 years
Shares reserved for issuance	2,969,486
Stock options granted	479,085

Stockholders' Deficit - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of outstanding options, Granted		0	0
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of outstanding options, Beginning balance	727,873
Number of outstanding options, Granted	479,085
Number of outstanding options, Cancelled	(16,810)
Number of outstanding options, Ending Balance	1,190,148		727,873
Number of outstanding options, Vested and expected to vest at March 31, 2022	1,190,148
Weighted average exercise price, Beginning balance	$ 6.99
Weighted average exercise price, Granted	8.05
Weighted average exercise price, Cancelled	6.99
Weighted average exercise price, Ending balance	7.42		$ 6.99
Weighted average exercise price, Vested and expected to vest at March 31, 2022	$ 7.42
Weighted-average remaining contractual term (in years)	9 years 9 months 18 days		9 years 11 months 8 days
Weighted-average remaining contractual term (in years), Vested and expected to vest at March 31, 2022	9 years 9 months 18 days
Aggregate intrinsic value	$ 7,907		$ 765
Aggregate intrinsic value, Vested and expected to vest at March 31, 2022	$ 7,907

Stockholders' Deficit - Summary of Assumptions used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.90%
Risk-free interest rate, maximum	2.50%
Expected volatility, minimum	88.10%
Expected volatility, maximum	89.50%
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days

Stockholders' Deficit - Summary of Assumptions used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants (Parenthetical) (Details) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021
Stockholders Equity Note [Abstract]
Stock options granted	0	0

Stockholders' Deficit - Schedule of Stock-based Compensation Expense (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 272
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	201
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 71

Stockholders' Deficit - Schedule of Common Stock Reserved for Future Issuance (Details)	Mar. 31, 2022 shares
Class Of Stock [Line Items]
Common stock reserved for future issuance	7,290,497
Common Stock Warrants
Class Of Stock [Line Items]
Common stock reserved for future issuance	5,883,500
Common Stock Options Outstanding
Class Of Stock [Line Items]
Common stock reserved for future issuance	1,190,148
Shares Available for Issuance Under the 2021 Plan
Class Of Stock [Line Items]
Common stock reserved for future issuance	216,849

Subsequent Events - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended
	May 03, 2022	Apr. 18, 2022	Apr. 30, 2022	Mar. 31, 2021	Mar. 31, 2024	Jun. 30, 2023	Dec. 15, 2022	Apr. 22, 2022	Mar. 31, 2022	Dec. 31, 2021
Subsequent Event [Line Items]
Common stock reserved for future issuance									7,290,497
Increase in number of authorized shares of common stock									50,000,000	50,000,000
Common Stock
Subsequent Event [Line Items]
Sale of common stock				1,606,815
Stock Option
Subsequent Event [Line Items]
Common stock reserved for future issuance									1,190,148
Subsequent Event
Subsequent Event [Line Items]
Increase in number of authorized shares of common stock								50,000,000
Subsequent Event \| Initial Public Offering
Subsequent Event [Line Items]
Increase in number of authorized shares of common stock	500,000,000
Increase in number of authorized shares of preferred stock	50,000,000
Subsequent Event \| Initial Public Offering \| Common Stock
Subsequent Event [Line Items]
Sale of common stock	13,529,750
Public offering price per share	$ 17.00
Net proceeds from initial public offering	$ 210,300,000
Underwriting discounts, commissions and offering costs	$ 19,700,000
Subsequent Event \| 2022 Incentive Award Plan
Subsequent Event [Line Items]
Number of shares initially available for issuance under awards granted			4,900,000
Plan term			The 2022 Plan became effective in connection with the Company’s IPO and will remain in effect until the tenth anniversary of its effective date, which will be April 28, 2032, unless earlier terminated by the Company’s board of directors. The number of shares of the Company's common stock initially available for issuance under awards granted pursuant to the 2022 Plan was the sum of (1) 4,900,000 shares of the Company’s common stock, plus (2) any shares remaining available for issuance under the 2021 Plan as of the effective date of the 2022 Plan, plus (3) any shares subject to outstanding awards under the 2021 Plan as of the effective date of the 2022 Plan that become available for issuance under the 2022 Plan thereafter in accordance with its terms.
Plan expiration date			Apr. 28, 2032
Percentage of shares issued from outstanding number of shares			5.00%
Shares issuance, beginning year			2023
Shares issuance, ending year			2032
Subsequent Event \| 2022 Incentive Award Plan \| Stock Option
Subsequent Event [Line Items]
Number of shares initially available for issuance under awards granted			132,799
Subsequent Event \| 2022 Employee Stock Purchase Plan
Subsequent Event [Line Items]
Percentage of shares issued from outstanding number of shares			1.00%
Shares issuance, beginning year			2023
Shares issuance, ending year			2032
Purchase price of common stock, percent			85.00%
Common stock reserved for future issuance			410,000
Number of shares authorized			10,000,000
August 2021 Notes \| Subsequent Event \| Initial Public Offering \| Common Stock
Subsequent Event [Line Items]
Conversion of notes to common stock	10,672,138
Loan Agreement \| Term Loan \| Subsequent Event
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 75,000,000.0
Debt instrument, minimum draw amount		$ 5,000,000.0
Debt instrument, basis spread on variable rate		5.00%
Debt instrument, interest rate		4.55%
Debt instrument, interest rate per annum		2.85%
Debt instrument, payment terms		The monthly payments consist of interest-only through June 1, 2025 or, if prior to April 30, 2025, (x) the conditions to Term Loan 3 have been satisfied and (y) the Company has reasonably determined that (i) the HIL-214 Vaccine Trial has achieved the protocol-specified primary efficacy endpoint and (ii) HIL-214 has demonstrated acceptable safety results in the HIL-214 Vaccine Trial, and, as a result, the Company supports the initiation of a Phase 3 registrational trial as the next immediate step in the development of HIL-214, in each case subject to reasonable verification by Hercules, through June 1, 2026. Subsequent to the interest-only period, the Term Loans will be payable in equal monthly installments of principal, plus accrued and unpaid interest, through the maturity date of May 1, 2027.
Debt instrument, frequency of periodic payment		monthly
Debt instrument, maturity date		May 01, 2027
Debt instrument, final payment fee		$ 2,100,000
Percentage of original principal amount payable		7.15%
Percentage of interest upon event of default		4.00%
Loan Agreement \| Term Loan \| Subsequent Event \| Prime Rate
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate		1.05%
Loan Agreement \| Term Loan \| Subsequent Event \| Maximum
Subsequent Event [Line Items]
Percentage of prepayment fee on outstanding principal balance		2.00%
Loan Agreement \| Term Loan 1 \| Subsequent Event
Subsequent Event [Line Items]
Debt instrument, borrowed amount		$ 5,000,000.0
Loan Agreement \| Term Loan 1 \| Scenario Forecast \| Maximum
Subsequent Event [Line Items]
Remaining borrowing capacity						$ 15,000,000.0	$ 10,000,000.0
Loan Agreement \| Term Loan 2 \| Scenario Forecast \| Maximum
Subsequent Event [Line Items]
Remaining borrowing capacity						$ 20,000,000.0
Loan Agreement \| Term Loan 3 \| Scenario Forecast \| Maximum
Subsequent Event [Line Items]
Remaining borrowing capacity					$ 25,000,000.0