0001558370-22-003614 | 10-K | XBRL Viewer

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 291,064	$ 39,045
Prepaid expenses and other current assets	7,636	904
Total current assets	298,700	39,949
Property and equipment, net	6,261	3,037
Other non-current assets	872	541
Total assets	305,833	43,527
Current liabilities:
Accounts payable	706	1,602
Accrued expenses and other current liabilities	6,013	1,757
Total current liabilities	6,719	3,359
Deferred rent, net of current portion	396
Total liabilities	7,115	3,359
Commitments and contingencies (Note 9)
Redeemable convertible preferred stock, par value $0.0001 (Note 6)		81,658
Stockholders' (deficit) equity:
Common stock, par value $0.0001; 150,000,000 and 113,259,306 shares authorized as of December 31, 2021 and December 31, 2020, respectively; 31,336,092 and 1,283,545 shares issued as of December 31, 2021 and December 31, 2020, respectively; 31,224,336 and 1,244,139 shares outstanding as of December 31, 2021 and December 31, 2020, respectively	3
Additional paid-in capital	392,384	1,021
Accumulated deficit	(93,669)	(42,511)
Total stockholders' (deficit) equity	298,718	(41,490)
Total liabilities, redeemable convertible preferred stock and stockholders' (deficit) equity	$ 305,833	$ 43,527

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
CONSOLIDATED BALANCE SHEETS
Redeemable convertible preferred stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares, authorized	150,000,000	113,259,306
Common stock, shares, issued	31,336,092	1,283,545
Common stock, shares, outstanding	31,224,336	1,244,139

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 35,926	$ 21,102
General and administrative	15,201	5,565
Total operating expenses	51,127	26,667
Loss from operations	(51,127)	(26,667)
Other (expense) income:
Interest and other (expense) income, net	(31)	144
Total other (expense) income, net	(31)	144
Net loss	$ (51,158)	$ (26,523)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (8.16)	$ (24.00)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (8.16)	$ (24.00)
Weighted-average common shares outstanding, basic (in shares)	6,267,776	1,105,260
Weighted-average common shares outstanding, diluted (in shares)	6,267,776	1,105,260

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Total
Beginning Balances at Dec. 31, 2019						$ 31,816
Beginning Balances (in shares) at Dec. 31, 2019						37,269,149
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock, net of issuance costs				$ 49,842
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)				48,030,736
Ending Balances at Dec. 31, 2020				$ 79,597		$ 81,658
Ending Balances (in shares) at Dec. 31, 2020				82,879,139		85,299,885
Beginning Balances at Dec. 31, 2019		$ 470	$ (15,988)			$ (15,518)
Beginning Balances (in shares) at Dec. 31, 2019	1,004,310
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		214				214
Issuance of common stock upon exercise of stock options (in shares)	129,607
Vesting of restricted common stock		1				1
Vesting of restricted common stock (in shares)	95,770
Vesting of early exercised options		11				11
Vesting of early exercised options (in shares)	14,452
Stock based compensation		325				325
Net loss			(26,523)			(26,523)
Ending Balances at Dec. 31, 2020		1,021	(42,511)			(41,490)
Ending Balances (in shares) at Dec. 31, 2020	1,244,139
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock upon initial public offering						$ (197,489)
Conversion of redeemable convertible preferred stock upon initial public offering (in shares)						(138,821,984)
Issuance of redeemable convertible preferred stock, net of issuance costs					$ 115,831
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)					53,522,099
Ending Balances (in shares) at Dec. 31, 2021						0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of redeemable convertible preferred stock upon initial public offering	$ 2	197,487				$ 197,489
Conversion of redeemable convertible preferred stock upon initial public offering (in shares)	19,185,183
Issuance of common stock from initial public offering, net of issuance costs	$ 1	190,690				190,691
Issuance of common stock from initial public offering, net of issuance costs (in shares)	10,436,250
Issuance of common stock upon exercise of stock options		410				410
Issuance of common stock upon exercise of stock options (in shares)	223,838
Vesting of restricted common stock (in shares)	11,537
Vesting of early exercised options		250				250
Vesting of early exercised options (in shares)	123,389
Stock based compensation		2,526				2,526
Net loss			(51,158)			(51,158)
Ending Balances at Dec. 31, 2021	$ 3	$ 392,384	$ (93,669)			$ 298,718
Ending Balances (in shares) at Dec. 31, 2021	31,224,336

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (51,158)	$ (26,523)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	1,117	326
Loss on disposal of property and equipment	74	20
Stock based compensation expense	2,526	325
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(6,733)	(311)
Other non-current assets	(331)	(541)
Accounts payable	(715)	631
Accrued expenses and other current liabilities	3,962	578
Deferred rent	396	(75)
Net cash used in operating activities	(50,862)	(25,570)
Cash flows from investing activities:
Purchases of property and equipment	(4,580)	(2,318)
Net cash used in investing activities	(4,580)	(2,318)
Cash flows from financing activities:
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	115,831	49,842
Proceeds from issuance of common stock upon initial public offering, net of issuance costs	190,691
Proceeds from exercise of stock options	410	213
Proceeds from the early exercise of stock options	529	34
Net cash provided by financing activities	307,461	50,089
Net increase in cash and cash equivalents	252,019	22,201
Cash and cash equivalents at beginning of year	39,045	16,844
Cash and cash equivalents at end of year	291,064	39,045
Supplemental cash flow disclosures:
Purchases of property and equipment included in accounts payable and accrued expenses	155	320
Conversion of preferred stock to common stock upon initial public offering	197,489
Vesting of restricted stock subject to repurchase		1
Vesting of options early exercised subject to repurchase	$ 250	$ 11

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements reflect the operations of the Company and have been prepared in conformity with generally accepted accounting principles in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB).

Principles of Consolidation

The accompanying consolidated financial statements include those of the Company and its wholly-owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and expenses, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to accrual and prepayment of research and development expenses and stock-based compensation. The Company bases its estimates on historical experience, known trends, and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts, and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions.

Segment Information

The Company manages its operations as a single segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of assessing performance and making operating decisions. All of the Company's long-lived assets are located in the United States.

Cash and Cash Equivalents

Cash and cash equivalents consist of standard checking accounts and money market account funds that invest primarily in U.S. government-backed securities and treasuries. The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents are stated at cost, which is substantially equivalent to fair value. As of December 31, 2021 and 2020, the Company has no restricted cash.

Concentrations of Credit Risk and Off-Balance Sheet Risk

Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. Periodically, the Company may maintain deposits in financial institutions in excess of government insured limits. Management believes that the Company is not exposed to significant credit risk as the Company’s deposits are held at financial institutions that management believes to be of high credit quality, and the Company has not experienced any losses on these deposits.

Fair Value Measurements

ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the

Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the assets or liability and are developed based on the best information available under the circumstances. ASC 820 identifies fair value as the price that would be received to sell an asset or paid to transfer a liability, in an orderly transaction between market participants at the measurement date.

As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tiered value hierarchy that distinguishes between the following:

●

Level 1—Quoted prices in active markets for identical assets or liabilities.

●

Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

●

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies, and similar techniques.

To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

There have been no changes to the valuation methods utilized by the Company during the years ended December 31, 2021 and 2020. The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of financial instruments between levels during the years ended December 31, 2021 and 2020. The carrying amounts of accounts payable and accrued expenses approximate their fair values due to their short-term nature.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight line method over the estimated useful life of each asset as follows:


	Estimated Useful Life
Laboratory equipment	5 years
Computer equipment	3 years
Furniture and fixtures	5 years
Leasehold improvements	Lesser of estimated useful life or remaining lease term

Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated once placed into service. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in other (expense) income. Expenditures for repairs and maintenance that do not improve or extend the life of the respective assets are expensed in operations as incurred.

Impairment of Long-Lived Assets

The Company evaluates its long-lived assets, which consist primarily of property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets 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 by the amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no impairment losses recognized during the years ended December 31, 2021 and 2020.

Redeemable Convertible Preferred Stock

The Company recorded redeemable convertible preferred stock at fair value upon issuance, net of any issuance costs. The Company classified stock that was redeemable in circumstances outside of the Company’s control outside of permanent equity. No accretion was recognized as the contingent events that could give rise to redemption were not deemed probable.

Deferred Offering Costs

The Company capitalizes incremental legal, professional accounting and other third-party fees that are incurred in the course of preparing for a financing as other non-current assets until the offering is consummated. At the time of the completion of the offering, the costs are reclassified as a reduction of the proceeds of the financing as part of additional paid-in-capital. Should the offering be terminated, deferred offering costs are charged to operations during the period in which the offering is terminated.

Contingencies

The Company records liabilities for legal and other contingencies when information available to the Company indicates that it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Legal costs in connection with legal and other contingencies are expensed as costs are incurred. No liabilities for legal and other contingencies were accrued as of December 31, 2021 and 2020.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, contract research organizations (CROs), business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and its executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. The Company has not incurred any material costs as a result of such indemnifications and is not currently aware of any indemnification claims.

Rent Expense

The Company’s real estate operating lease provides for scheduled annual rent increases throughout the lease term. In accordance with ASC Topic 840, Leases (ASC 840), the Company recognizes the effects of the scheduled rent increases on a straight-line basis over the full term of the lease. Tenant improvement allowances, if any, provided by the landlord are recorded as deferred rent and amortized as a reduction to rent expense over the lease term.

Research and Development Costs

Research and development costs are charged to expense as incurred. Research and development costs consist of direct and allocated costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, facilities costs, third-party license fees related to technology with no alternative future use, laboratory supplies, depreciation, manufacturing expenses, preclinical expenses, consulting and other contracted services. Costs for certain research and development activities are recognized based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the consolidated financial statements as prepaid or accrued research and development.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Stock-Based Compensation

The Company’s stock-based compensation program allows for grants of stock options and restricted stock awards. Grants are awarded to employees and non-employees, including the Company’s board of directors.

The Company accounts for its stock-based compensation in accordance with ASC Topic 718, Compensation-Stock Compensation (ASC 718). ASC 718 requires all stock-based payments to employees, non-employees and directors, to be recognized as expense in the consolidated statements of operations based on their grant date fair values. The Company estimates the fair value of options granted using the Black-Scholes option pricing model (Black-Scholes) for stock option grants to both employees and non-employees. The fair value of the Company’s common stock is used to determine the fair value of restricted stock awards.

The Company’s stock-based compensation awards are subject to service-based vesting conditions. Compensation expense related to awards to employees, directors and non-employees with service-based vesting conditions is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term.

Black-Scholes requires inputs based on certain subjective assumptions, including (i) the expected stock price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate and (iv) expected dividends. The Company determines the expected volatility using a blended approach encompassing its historical experience and the historical volatility of a peer group of comparable publicly traded companies with product candidates in similar stages of development to the Company’s product candidates. The Company uses the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to employees and non-employees whereby, the expected term equals the arithmetic average of the vesting term and the original contractual term of the options due to its lack of sufficient historical data. The risk-free interest rate is based on U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company recognizes forfeitures as they occur.

Prior to the Company’s IPO, there was no public market for its common stock, and consequently, the estimated fair value of its common stock was determined by the board of directors as of the date of each option grant, with input from management, considering third-party valuations of its common stock as well as its board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the grant. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation (Practice Aid). The Practice Aid identifies various available methods for allocating the enterprise value across classes of series of capital stock in determining the fair value of the Company’s common stock at each valuation date.

Subsequent to the Company’s IPO, the fair value of the common stock underlying the stock-based awards is the closing price of the Company’s common stock on the date of grant.

Restricted common stock awards are subject to service based vesting and repurchase rights. Accordingly, the Company has recorded the proceeds from the issuance of restricted stock as a liability in the consolidated balance sheets. This restricted stock liability is reclassified into stockholders’ (deficit) equity as the restricted stock vests.

The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Income Taxes

Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes (ASC 740), which provides for deferred taxes using an asset and liability approach. The Company accounts for income taxes using 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 recognized in the consolidated financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the consolidated

financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by first evaluating the tax position to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes.

Net Loss per Share

The Company follows the two-class method when computing net loss per share, as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. During periods of loss, there is no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company.

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the diluted net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. Given that the Company recorded a net loss for each of the periods presented, there is no difference between basic and diluted net loss per share since the effect of common stock equivalents would be antidilutive and are, therefore, excluded from the diluted net loss per share calculation.

Emerging Growth Company Status

The Company qualifies as an “emerging growth company” (EGC), as defined in the Jumpstart Our Business Startups Act (JOBS Act) and may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not EGCs. The Company may take advantage of these exemptions until it is no longer an EGC under Section 107 of the JOBS Act, which provides that an EGC can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected to avail itself of the extended transition period and, therefore, while the Company is an EGC it will not be subject to new or revised accounting standards the same time that they become applicable to other public companies that are not EGCs, unless it chooses to early adopt a new or revised accounting standard. As a result of this election, the consolidated financial statements may not be comparable to companies that comply with public company FASB standards’ effective dates.

Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the FASB or other standard-setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and non-public companies, the Company can adopt the new or revised standard at the time non-public companies adopt the new or revised standard and can do so until such time that the

Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for non-public companies. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial statements and disclosures.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes all existing lease guidance. This guidance offers specific accounting guidance for a lessee, a lessor and sale and leaseback transactions. The new standard requires lessees to recognize an operating lease with a term greater than one year on their balance sheets as a right-of-use asset and corresponding lease liability, measured at the present value of the lease payments. Lessees are required to classify leases as either finance or operating leases. If the lease is effectively a financed-purchase by the lessee, the lease is classified as a financing lease; otherwise the lease is classified as an operating lease. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. Topic 842 provides accounting guidance for transactions that meet specific criteria for a leaseback transaction. If the criteria are not met, the transaction is considered a “failed sale” and the transaction must be accounted for as a financing arrangement. For EGCs, such as the Company, ASU 2016-02, as amended, will be effective for annual reporting periods beginning after December 15, 2021 and interim periods within those fiscal years, with early adoption permitted. For public entities, ASU No. 2016-02 was effective for annual periods beginning after December 15, 2018, including interim periods within these annual periods. The Company is currently evaluating the full impact that the adoption of ASU 2016-02 is expected to have on its consolidated financial statements; however, the adoption of ASU 2016-02 will require the recognition at the adoption date of both a lease liability, based on the present value of future lease payments, and a corresponding right-to-use asset, which the Company expects to be material. The future lease payment obligation as of December 31, 2021 is disclosed in Note 9, Commitments and Contingencies.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This ASU requires that credit losses for financial instruments measured at amortized cost be reported using an expected losses model rather than the incurred losses model that is currently used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, this standard requires allowances to be recorded instead of reducing the amortized cost of the investment. ASU 2016-13 limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value and requires the reversal of previously recognized credit losses if fair value increases. For EGCs, such as the Company, the new standard will be effective beginning January 1, 2023. For public entities, the standard was effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company is currently evaluating the potential impact this ASU may have on its financial position and results of operations upon adoption.

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740)—Simplifying the Accounting for Income Taxes (ASU 2019-12), which is intended to simplify the accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends certain aspects of the existing guidance to improve consistent application. For EGCs, such as the Company, ASU 2019-12 is effective beginning January 1, 2022, with early adoption permitted. The Company is currently evaluating the potential impact that this ASU may have on its financial position and results of operations, as well as the timing of its adoption of this standard.

Fair Value Measurements

12 Months Ended

Dec. 31, 2021

Fair Value Measurements

Fair Value Measurements

3. Fair Value Measurements

The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands):


	Fair Value Measurements at
	December 31, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	290,814	$	—	$	—	$	290,814
Total	$	290,814	$	—	$	—	$	290,814


	Fair Value Measurements at
	December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	38,795	$	—	$	—	$	38,795
Total	$	38,795	$	—	$	—	$	38,795

Cash and Cash Equivalents—Cash and cash equivalents of $291.1 million and $39.0 million as of December 31, 2021 and December 31, 2020, respectively, consisted of money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock

12 Months Ended

Dec. 31, 2021

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock

6. Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock

Redeemable Convertible Preferred Stock

Upon the closing of the IPO in November 2021, the Company’s Preferred Stock automatically converted into 19,185,183 shares of common stock. As of December 31, 2021, the Company did not have any shares of redeemable convertible preferred stock authorized, issued or outstanding. Redeemable convertible preferred stock consisted of the following at December 31, 2020 (in thousands, except share amounts):


	December 31, 2020
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
	85,299,885	85,299,885	$	81,658	$	88,377	11,788,435

On October 27, 2016, the Company entered into a Series Seed Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 691,641 shares of Series Seed redeemable convertible preferred stock (Series Seed Preferred Stock) at a purchase price of $0.8675 per share for aggregate proceeds of $0.6 million. On March 3, 2017, the Company entered into a second closing of Series Seed Preferred Stock, whereby the Company issued 576,368 shares at a purchase price of $0.8675 per share for aggregate proceeds of $0.5 million. On May 16, 2017, the Company completed the milestone closing of Series Seed Preferred Stock upon the satisfaction of stated milestones pursuant to the Series Seed Preferred Stock Purchase Agreement. In connection with this milestone closing, a total of 1,152,737 shares of Series Seed Preferred Stock were issued at a purchase price of $0.8675, for aggregate gross proceeds of $1.0 million. The Company incurred issuance costs of less than $0.1 million in connection with each of these closings.

On December 14, 2018, the Company entered into a Series A Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 34,848,403 shares of Series A redeemable convertible preferred stock (Series A Preferred Stock), 24,015,368 of which were issued at a purchase price of $1.041 per share for gross cash proceeds of $25.0 million, and 10,833,035 of which were issued in satisfaction of principal and interest on convertible notes outstanding held by the Company of $9.0 million. Pursuant to the Series A Preferred Stock Purchase Agreement, the Company also agreed to issue up to an additional 24,015,368 shares at a price of $1.041 per share upon the achievement of certain specified milestones.

On January 22, 2020, upon waiver of stated milestones in the Series A Preferred Stock Purchase Agreement, the Company issued 24,015,368 shares of Series A Preferred Stock at a purchase price of $1.041 per share for aggregate proceeds of $25.0 million. The Company incurred issuance costs of less than $0.1 million. Pursuant to the Amended and Restated Series A Preferred Stock Purchase Agreement, on August 12, 2020, the Company agreed to issue an additional 24,015,368 shares of Series A Preferred Stock at a purchase price of $1.041 per share for aggregate proceeds of $25.0 million. The Company incurred issuance costs of $0.1 million.

On March 29, 2021, the Company entered into a Series B Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 53,522,099 shares of Series B redeemable convertible preferred stock (Series B Preferred Stock, together with the Series Seed Preferred Stock and Series A Preferred Stock, Preferred Stock) at a price of $2.172 per share for gross cash proceeds of $116.2 million. The Company incurred issuance costs of $0.4 million. As part of the issuance of Series B Preferred Stock, the liquidation preferences of the Preferred Stock were modified such that, in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or a deemed liquidation event, the holders of Preferred Stock then outstanding shall be entitled to be paid out equal to the greater of (i) the applicable original issue price, plus any dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Preferred Stock been converted into common stock.

The Company amended the articles of incorporation upon the issuance of the Series B Preferred Stock and the rights and preferences of the outstanding shares of Series Seed Preferred Stock and Series A Preferred Stock were adjusted. The Company considered if the adjustment to the previously issued shares of Preferred Stock represents an extinguishment or a modification to the outstanding mezzanine classified instruments. The adjustments to the outstanding shares of Preferred Stock were qualitatively insignificant. As a result, the adjustments to the rights and preferences of the outstanding shares of Preferred Stock qualified as a modification and no accounting was required as holders of these classes of equity did not receive any incremental value in the transaction.

Upon issuance of each class of redeemable convertible preferred stock, the Company assessed the embedded conversion and liquidation features of the shares and determined that such features did not require the Company to separately account for these features. The Company also concluded that no beneficial conversion feature existed on the issuance date of each class of redeemable convertible preferred stock.

Prior to the conversion of the Preferred Stock into shares of common stock upon the completion of the IPO in November 2021, the Preferred Stock had the following rights and preferences:

Conversion Rights

Each share of Preferred Stock is convertible at the option of the holder at any time after the date of issuance. The number of shares of common stock to be issued in the event of a conversion is determined by dividing the original issue price of $0.8675 for the Series Seed Preferred Stock, $1.041 for the Series A Preferred Stock, and $2.172 for the Series B Preferred Stock by the conversion price then in effect. The conversion price for each of the Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock was initially $0.8675, $1.041, and $2.172 per share, respectively, subject to adjustment under certain circumstances, including but not limited to certain additional issuances of common shares.

The Preferred Stock automatically convert at either (i) the closing of a firm-commitment underwritten public offering resulting in at least $75 million of net proceeds to the Company, upon which all outstanding Preferred Stock shall automatically be converted into common shares, at the then effective Series Seed conversion price, Series A conversion price, or Series B conversion price, respectively or (ii) at the election of the required majority of Preferred Stock holders, upon which all or any portion of the outstanding Preferred Stock shall automatically be converted into common shares, at the then effective Series Seed conversion price, Series A conversion price, and or Series B conversion price, respectively.

Dividends

The holders of Preferred Stock shall be entitled to receive non-cumulative cash dividends, out of any assets legally available therefor, prior and in preference to any declaration or payment of any dividend on shares of common stock (payable other than in common stock or other securities and rights convertible into or entitling the holder thereof to receive, directly or indirectly, additional shares of common stock of the Company) at a rate of eight percent of the applicable original issue price per share of Preferred Stock per annum, payable only when, as and if declared by the Company’s board of directors.

The Company shall not declare, pay or set aside any dividends on shares of any other class or series of capital stock of the Company (other than dividends on shares of common stock payable in shares of common stock) unless (in addition to the obtaining of any consents required otherwise by the Company’s restated certificate of incorporation) the holders of Preferred Stock then outstanding shall first receive, or simultaneously receive, in addition to the eight percent non-cumulative dividend described above, a dividend on each outstanding share of Preferred Stock in an amount at least equal to the dividend payable on each share of such class or series determined as if all shares of such class or series had been converted into common stock. No dividends were declared or paid during the years ended December 31, 2021 or 2020.

Liquidation Preference

Upon liquidation, dissolution, or winding up of business or a deemed liquidation event, the holders of the Preferred Stock shall be entitled to be paid out the greater of (i) the applicable original issue price, plus any dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Preferred Stock been converted into common stock. If, upon any such event, the assets available for distribution are insufficient to satisfy the liquidation payment to holders of Preferred Stock in full, the holders of Preferred Stock shall share ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

Voting Rights

Except as provided by law or by other provisions of the instruments pursuant to which each series of Preferred Stock was issued, holders of the Preferred Stock and common stockholders’ vote together as one class on an “as-converted basis.” On any matter presented to the stockholders of the Company for their action or consideration at any meeting of stockholders of the Company, each holder of Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock is entitled to cast the number of votes equal to the number of whole shares of common stock

into which the shares of Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock held by such holder are convertible as of the record date for determining shares entitled to vote on such matter. The holders of the shares of Series A Preferred Stock, exclusively and as a separate class, are entitled to elect three directors of the Company. The holders of the shares of Series B Preferred Stock, exclusively and as a separate class, are entitled to elect one director of the Company. The holders of the shares of common stock and Preferred Stock, exclusively and voting together as a single class, are entitled to elect three directors of the Company.

Common Stock

As of December 31, 2021, the Company’s certificate of incorporation, as amended and restated effective upon the completion of the IPO, authorized the Company to issue 150,000,000 shares of common stock, par value $0.0001 per share. The holders of common stock are entitled to one vote for each share held on all matters submitted to a vote of the stockholders. The holders of common stock do not have any cumulative voting rights. Holders of common stock are entitled to receive ratably any dividends declared by the board of directors out of funds legally available for that purpose, subject to any preferential dividend rights of any outstanding preferred stock. Common stock has no preemptive rights, conversion rights or other subscription rights or redemption or sinking fund provisions. In the event of liquidation, dissolution or winding up, holders of common stock will be entitled to share ratably in all assets remaining after payment of all debts and other liabilities and any liquidation preference of any outstanding preferred stock.

As of December 31, 2020, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 113,259,306 shares of common stock, par value $0.0001 per share. The holders of common stock are entitled to one vote for each share of common stock. Subject to the payment in full of all preferential dividends to which the holders of the Preferred Stock are entitled, the holders of common stock shall be entitled to receive dividends out of funds legally available. In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, after the payment or provision for payment of all debts and liabilities of the Company and all preferential amounts to which the holders of Preferred Stock are entitled with respect to the distribution of assets in liquidation, the holders of common stock shall be entitled to share ratably in the remaining assets of the Company available for distribution.

Shares Reserved for Future Issuance

The Company has reserved the following shares of common stock for future issuance at December 31:


	2021	2020
Exercise of outstanding stock options	3,461,870	1,625,256
Outstanding restricted stock	—	11,537
Future awards under the 2021 Plan	2,843,255	—
Future awards under the 2021 ESPP	278,762	—
Future awards under the 2016 Plan	—	360,306
Conversion of redeemable convertible preferred stock	—	11,788,435
Total shares of authorized common stock reserved for future issuance	6,583,887	13,785,534

Preferred Stock

As of December 31, 2021, the Company was authorized to issue 10,000,000 shares of undesignated preferred stock, $0.0001 par value, in one or more series and to fix the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting, or the designation of, such series, any or all of which may be greater than the rights of common stock. The Company was not authorized to issue any such shares as of December 31, 2020. As of December 31, 2021, there were no shares of undesignated preferred stock issued or outstanding.

Stock Based Compensation

12 Months Ended

Dec. 31, 2021

Stock Based Compensation

Stock Based Compensation

7. Stock-Based Compensation

2021 Plan

In September 2021 the Company’s board of directors adopted, and in October 2021 the Company’s stockholders approved, the 2021 Plan, which became effective as of the date immediately prior to the date of the effectiveness of the registration statement for the IPO. The 2021 Plan allows the board of directors to grant incentive stock options or non-qualified stock options, restricted stock, restricted stock units, and other equity awards to the Company’s officers, employees, directors, and other key persons. In addition, the 2021 Plan includes a provision that allows for an automatic annual increase of 4% in the number of shares of common stock available for issuance under the 2021 Plan. The 2021 Plan replaced the 2016 Plan and no additional awards will be granted under the 2016 Plan following the closing of the IPO. The 2016 Plan will continue to govern the outstanding equity awards granted thereunder. The total number of shares of common stock authorized for issuance under the 2021 Plan as of December 31, 2021 was 3,986,270 shares. There were no shares of common stock authorized for issuance under the 2021 Plan as of December 31, 2020.

As of December 31, 2021, the Company had issued only stock options under the 2021 Plan. Stock options issued comprise of service-based awards granted to employees. Vesting of stock options is subject to the recipient’s continued employment or service. The maximum term of options granted under the 2021 Plan is ten years, and stock options typically vest over a four-year period.

2021 Employee Stock Purchase Plan

In September 2021, the Company’s board of directors adopted, and in October 2021 the Company’s stockholders approved, the ESPP, which became effective as of the date immediately prior to the date of the effectiveness of the registration statement for the IPO. The ESPP is administered by the person or persons appointed by the Company’s board of directors for such purpose. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 278,762 shares of common stock. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1st of each year beginning in 2022 and continuing through and including 2031 by the least of (i) 1% of the outstanding number of shares of our common stock of the immediately preceding December 31, (ii) 557,524 shares or (iii) such number of shares as determined by the ESPP administrator. As of December 31, 2021, no offering periods have commenced under the 2021 ESPP and 278,762 shares remained available for issuance.

2016 Plan

The 2016 Plan provides for the Company to grant incentive stock options or non-qualified stock options, restricted stock, restricted stock units, and other equity awards to employees, directors, and consultants of the Company. The 2016 Plan is administered by the board of directors of the Company or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting, and other restrictions are determined at the discretion of the board of directors, or its committee if so delegated. The 2016 Plan allows for early exercise of all stock option grants if authorized by the board of directors at the time of grant. The shares of common stock issued from the early exercise of stock options are restricted and continue to vest over the original service based vesting condition of the original stock option award. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination.

The total number of shares of common stock authorized for issuance under the 2016 Plan as of December 31, 2021 and 2020 was 2,318,855 shares and 1,997,099 shares, respectively.

Stock-Based Compensation

For the years ended December 31, 2021 and 2020, the Company recorded stock-based compensation expense of $2.5 million and $0.3 million. Stock compensation expense for 2021 and 2020 included less than $0.1 million related to restricted stock in both years and $2.5 million and $0.3 million related to stock options in 2021 and 2020, respectively.

Stock-based compensation expense recorded as research and development and general and administrative expenses in the consolidated statements of operations is as follows (in thousands):


	Year Ended December 31,
	2021		2020
Research and development expenses	$	878	$	107
General and administrative expenses		1,648		218
Total	$	2,526	$	325

Stock Option Valuation

The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted for the years then ended:


	December 31,		December 31,
	2021		2020
Risk‑free interest rate	1.15	%	0.53	%
Expected volatility	73	%	75	%
Expected dividend yield	—		—
Expected term (in years)	6.01		5.99

Early Exercise of Unvested Stock Options

Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding shares until those shares vest according to their respective vesting schedules. Cash received from employee exercises of unvested options is included in current liabilities on the balance sheet. Amounts recorded are reclassified to common stock and additional paid-in capital as the shares vest. Vesting can occur in the year of exercise and thereafter. There were 111,756 and 27,869 unvested shares related to early exercises of stock options as of December 31, 2021 and December 31, 2020, respectively. In the years ended December 31, 2021 and 2020, the liability associated with the unvested early exercise of stock options was $0.3 million and less than $0.1 million, respectively.

Stock Options

The following table summarizes the Company’s stock option activity since December 31, 2020:


		Weighted‑		Weighted‑
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value (2)
				(in years)	(in thousands)
Outstanding as of December 31, 2020	1,625,256	$	1.88
Granted	2,311,485		14.67
Exercised	(431,687)		2.17
Forfeited	(43,184)		3.14
Outstanding as of December 31, 2021	3,461,870	$	10.38	9.12	$	26,730
Exercisable as of December 31, 2021 (1)	2,359,876	$	5.84	8.79	$	26,730
(1) This represents the number of vested and unvested options exercisable as of December 31, 2021.
(2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of December 31, 2021.

The aggregate intrinsic value of stock options exercised during the years ended December 31, 2021 and 2020 was $2.8 million and $0.1 million, while the company received $0.9 million and $0.2 million in proceeds for the exercise of these options, respectively.

The weighted-average grant-date fair value of stock options granted during the years ended December 31, 2021 and 2020 was $9.39 per share and $1.56 per share, respectively. As of December 31, 2021, there was $20.9 million of unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted-average period of 3.5 years.

Restricted Stock Awards

The Company issued restricted stock to its founders and certain officers of the Company. In general, the shares of restricted stock vest over a four-year period, with 25% of the shares vesting after one year, followed by monthly vesting over the remaining three years.

If the holders of the above restricted stock cease to have a business relationship with the Company, the Company may reacquire any unvested shares of restricted stock held by these individuals for the original purchase price or fair value, whichever is lower at the time of repurchase. The amounts received to date for the purchase price of restricted stock are immaterial. The unvested shares of restricted stock are not considered outstanding shares for accounting purposes until the shares vest.

A summary of unvested restricted stock during the year ended December 31, 2021 is as follows:


		Weighted‑
		Average
		Grant‑Date
	Shares	Fair Value
Unvested as of December 31, 2020	11,537	$	0.007
Vested	(11,537)		0.007
Unvested as of December 31, 2021	—	$	—

The total fair value of restricted stock vested during each of the years ended December 31, 2021 and 2020 was less than $0.1 million.

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Taxes

Income Taxes

8. Income Taxes

For the years ended December 31, 2021 and 2020, the Company recorded no income tax benefits for the net operating losses incurred or for the research and development tax credits generated in each period, due to its uncertainty of realizing a benefit from those items. All of the Company’s operating losses since inception have been generated in the United States.

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended December 31,
	2021		2020
Federal statutory income tax rate	21.0	%	21.0	%
State income taxes, net of federal benefit	6.1		6.2
Federal and state research and development tax credits	3.9		4.0
Non-deductible items	(0.3)		(0.2)
Change in deferred tax asset valuation allowance	(30.7)		(31.0)
Effective income tax rate	—	%	—	%

Net deferred tax assets as of December 31, 2021 and 2020 consisted of the following (in thousands):


		December 31,
		2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	25,124	$	11,214
Research and development tax credit carryforwards		3,237		1,236
Intangible assets		761		432
Salaries and wages		—		313
Stock compensation		430		80
Other		137		76
Total deferred tax assets		29,689		13,351
Deferred tax liabilities:
Property and equipment		(261)		(111)
Prepaid expenses		(485)		—
Total deferred tax liabilities		(746)		(111)
Valuation allowance		(28,943)		(13,240)
Net deferred tax assets	$	—	$	—

As of December 31, 2021, the Company had federal net operating loss carryforwards of $93.1 million, which may be available to offset future taxable income, of which $3.2 million of the total net operating loss carryforwards expire at various dates beginning in 2036, while the remaining $89.9 million do not expire but are limited in their usage to an annual deduction equal to 80% of annual taxable income. In addition, as of December 31, 2021, the Company had state net operating loss carryforwards of $88.0 million, which may be available to offset future taxable income and expire at various dates beginning in 2036. As of December 31, 2021, the Company also had federal and state research and development tax credit carryforwards of $2.3 million and $1.2 million, respectively, which may be available to reduce future tax liabilities and expire at various dates beginning in 2039 and 2034, respectively.

Utilization of the U.S. federal and state net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Section 382 and Section 383 of the Internal Revenue Code of 1986 (Code), and corresponding provisions of state law, due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income and tax liabilities. In general, an ownership change, as defined by Section 382 of the Code, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 5% over a three-year period. The Company has not conducted a study to assess whether a change of control has occurred or whether there have been multiple changes of control since inception due to the significant complexity and cost associated with such a study. If the Company has experienced a change of control, as defined by Section 382 of the Code, at any time since inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards may be subject to an annual limitation, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate, and then could be subject to additional adjustments. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research and development tax credit carryforwards before their utilization. Further, until a study is completed by the Company and any limitation is known, no amounts are being presented as an uncertain tax position.

The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets, which consist primarily of net operating loss carryforwards and research and development tax credit carryforwards. Management has considered the Company’s history of cumulative net losses incurred since inception, estimated future taxable income, and prudent and feasible tax planning strategies and has concluded that it is more likely than not that the Company will not realize the benefits of federal and state net deferred tax assets. Accordingly, a full valuation allowance has been established against the net deferred tax assets as of December 31, 2021 and 2020. The Company reevaluates the positive and negative evidence at each reporting period.

The valuation allowance increased by $15.7 million and $8.2 million for the year ending December 31, 2021 and 2020, respectively. The increase in the valuation allowance for deferred tax assets during the years ended December 31, 2021 and 2020 related primarily to the increases in net operating loss carryforwards and research and development tax credit carryforwards.

The Company assesses the uncertainty in its income tax positions to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more-likely-than-not threshold, the tax amount recognized in the consolidated financial statements is reduced by the largest benefit that has a greater than 50% likelihood of being realized upon the ultimate settlement with the relevant taxing authority. The Company’s policy is to recognize interest and penalties accrued on any uncertain tax positions as a component of income tax expense, if any, in its consolidated statements of operations. As of December 31, 2021 and 2020, the Company had not recorded any reserves for uncertain tax positions or related interest and penalties.

The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. Due to net operating losses incurred, the Company’s tax returns from inception to date are subject to examination by the taxing authorities.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Summary of Significant Accounting Policies

Basis Of Presentation

Basis of Presentation

Principles of Consolidation

The accompanying consolidated financial statements include those of the Company and its wholly-owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

Segment Information

Cash and Cash Equivalents

Concentrations of Credit Risk and Off-Balance Sheet Risk

Fair Value Measurements

As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tiered value hierarchy that distinguishes between the following:

●

Level 1—Quoted prices in active markets for identical assets or liabilities.

●

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight line method over the estimated useful life of each asset as follows:


	Estimated Useful Life
Laboratory equipment	5 years
Computer equipment	3 years
Furniture and fixtures	5 years
Leasehold improvements	Lesser of estimated useful life or remaining lease term

Impairment of Long-Lived Assets

Redeemable Convertible Preferred Stock

Deferred Offering Costs

Contingencies

Indemnification Agreements

Rent Expense

Research and Development Costs

Patent Costs

Stock-Based Compensation

Subsequent to the Company’s IPO, the fair value of the common stock underlying the stock-based awards is the closing price of the Company’s common stock on the date of grant.

Income Taxes

Net Loss per Share

Emerging Growth Company Status

Recently Issued Accounting Pronouncements

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Measurements

Schedule of fair value hierarchy for assets and liabilities measured at fair value on recurring basis


	Fair Value Measurements at
	December 31, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	290,814	$	—	$	—	$	290,814
Total	$	290,814	$	—	$	—	$	290,814


	Fair Value Measurements at
	December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	38,795	$	—	$	—	$	38,795
Total	$	38,795	$	—	$	—	$	38,795

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2021

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock

Schedule of Preferred Stock


	December 31, 2020
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
	85,299,885	85,299,885	$	81,658	$	88,377	11,788,435

Schedule of shares reserved for future issuance


	2021	2020
Exercise of outstanding stock options	3,461,870	1,625,256
Outstanding restricted stock	—	11,537
Future awards under the 2021 Plan	2,843,255	—
Future awards under the 2021 ESPP	278,762	—
Future awards under the 2016 Plan	—	360,306
Conversion of redeemable convertible preferred stock	—	11,788,435
Total shares of authorized common stock reserved for future issuance	6,583,887	13,785,534

Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Stock Based Compensation

Schedule of Stock-based compensation expense

Stock-based compensation expense recorded as research and development and general and administrative expenses in the consolidated statements of operations is as follows (in thousands):


	Year Ended December 31,
	2021		2020
Research and development expenses	$	878	$	107
General and administrative expenses		1,648		218
Total	$	2,526	$	325

Schedule of assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted


	December 31,		December 31,
	2021		2020
Risk‑free interest rate	1.15	%	0.53	%
Expected volatility	73	%	75	%
Expected dividend yield	—		—
Expected term (in years)	6.01		5.99

Summary of the stock option activity


		Weighted‑		Weighted‑
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value (2)
				(in years)	(in thousands)
Outstanding as of December 31, 2020	1,625,256	$	1.88
Granted	2,311,485		14.67
Exercised	(431,687)		2.17
Forfeited	(43,184)		3.14
Outstanding as of December 31, 2021	3,461,870	$	10.38	9.12	$	26,730
Exercisable as of December 31, 2021 (1)	2,359,876	$	5.84	8.79	$	26,730
(1) This represents the number of vested and unvested options exercisable as of December 31, 2021.
(2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of December 31, 2021.

Summary of unvested restricted stock


		Weighted‑
		Average
		Grant‑Date
	Shares	Fair Value
Unvested as of December 31, 2020	11,537	$	0.007
Vested	(11,537)		0.007
Unvested as of December 31, 2021	—	$	—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Taxes

Schedule of reconciliation of U.S. federal statutory income tax rate to effective income tax rate


	Year Ended December 31,
	2021		2020
Federal statutory income tax rate	21.0	%	21.0	%
State income taxes, net of federal benefit	6.1		6.2
Federal and state research and development tax credits	3.9		4.0
Non-deductible items	(0.3)		(0.2)
Change in deferred tax asset valuation allowance	(30.7)		(31.0)
Effective income tax rate	—	%	—	%

Schedule of net deferred tax assets

Net deferred tax assets as of December 31, 2021 and 2020 consisted of the following (in thousands):


		December 31,
		2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	25,124	$	11,214
Research and development tax credit carryforwards		3,237		1,236
Intangible assets		761		432
Salaries and wages		—		313
Stock compensation		430		80
Other		137		76
Total deferred tax assets		29,689		13,351
Deferred tax liabilities:
Property and equipment		(261)		(111)
Prepaid expenses		(485)		—
Total deferred tax liabilities		(746)		(111)
Valuation allowance		(28,943)		(13,240)
Net deferred tax assets	$	—	$	—

Nature of the Business (Details) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Oct. 22, 2021	Nov. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) shares
Subsidiary, Sale of Stock [Line Items]
Gross proceeds from issuance of common stock			$ 190,691
Redeemable convertible preferred stock, shares issued upon conversion \| shares		19,185,183		11,788,435
Reverse stock split ratio	0.1382
Net loss			51,158	$ 26,523
Accumulated deficit			93,669	42,511
Cash and cash equivalents			$ 291,064	$ 39,045
IPO
Subsidiary, Sale of Stock [Line Items]
Aggregate shares issued and sold \| shares		10,436,250
Stock price \| $ / shares		$ 20.00
Gross proceeds from issuance of common stock		$ 208,700
Net proceeds from issuance of common stock		$ 190,700
Redeemable convertible preferred stock, shares issued upon conversion \| shares		19,185,183
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Shares issued \| shares		1,361,250

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock - Redeemable Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Nov. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Preferred Stock Authorized	0		85,299,885
Preferred Stock Issued	0		85,299,885
Preferred stock outstanding	0		85,299,885	37,269,149
Carrying Value			$ 81,658	$ 31,816
Liquidation Preference			$ 88,377
Common stock issuable upon conversion		19,185,183	11,788,435
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Preferred Stock Authorized			2,420,746
Preferred Stock Issued			2,420,746
Preferred stock outstanding			2,420,746
Carrying Value			$ 2,061
Liquidation Preference			$ 2,100
Common stock issuable upon conversion			334,547
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Preferred Stock Authorized			82,879,139
Preferred Stock Issued			82,879,139
Preferred stock outstanding			82,879,139
Carrying Value			$ 79,597
Liquidation Preference			$ 86,277
Common stock issuable upon conversion			11,453,888

- Definition

Carrying amount, attributable to parent, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

+ References + Details

Stock Based Compensation - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Exercisable (in shares)	111,756	27,869
Aggregate Intrinsic Value
Proceeds from exercise of stock options	$ 410	$ 213
Stock options
Number of Shares
Outstanding at beginning of period (in shares)	1,625,256
Granted (in shares)	2,311,485
Exercised (in shares)	(431,687)
Forfeited (in shares)	(43,184)
Outstanding at end period (in shares)	3,461,870	1,625,256
Exercisable (in shares)	2,359,876
Weighted Average Exercise Price
Weighted-Average Exercise Price Outstanding at beginning period (in dollars per share)	$ 1.88
Weighted Average Exercise Price Granted (in dollars per share)	14.67
Weighted Average Exercise Price Exercised (in dollars per share)	2.17
Weighted Average Exercise Price Forfeited (in dollars per share)	3.14
Weighted Average Exercise Price Outstanding at end period (in dollars per share)	10.38	$ 1.88
Weighted Average Exercise Price Exercisable	$ 5.84
Weighted Average Contractual Term (in years)
Weighted Average Contractual Term, Outstanding (in years)	9 years 1 month 13 days
Weighted Average Contractual Term, Exercisable (in dollars per share)	8 years 9 months 14 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value Outstanding	$ 26,730
Aggregate Intrinsic Value, Exercisable	26,730
Aggregate intrinsic value of stock options exercised	2,800	$ 100
Proceeds from exercise of stock options	$ 900	$ 200
Weighted-average grant-date fair value of stock options granted	$ 9.39	$ 1.56
Unrecognized compensation cost	$ 20,900
Unrecognized compensation cost, weighted-average period for recognition	3 years 6 months

Income Taxes - Net deferred tax assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 25,124	$ 11,214
Research and development tax credit carryforwards	3,237	1,236
Intangible assets	761	432
Salaries and wages		313
Stock compensation	430	80
Other	137	76
Total deferred tax assets	29,689	13,351
Deferred tax liabilities:
Property and equipment	(261)	(111)
Prepaid expenses	(485)
Total deferred tax liabilities	(746)	(111)
Valuation allowance	(28,943)	(13,240)
Net deferred tax assets

Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net loss attributable to common stockholders	$ (51,158)	$ (26,523)
Denominator:
Weighted-average common shares outstanding, basic (in shares)	6,267,776	1,105,260
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (8.16)	$ (24.00)
Numerator:
Net loss attributable to common stockholders	$ (51,158)	$ (26,523)
Denominator:
Weighted-average common shares outstanding, diluted (in shares)	6,267,776	1,105,260
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (8.16)	$ (24.00)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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

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+ Details

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net of issuance costs	$ 18,034
Series A Redeemable Convertible Preferred Stock
Stock issuance costs		$ 158
Series B Redeemable Convertible Preferred Stock
Stock issuance costs	$ 420

Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Assets transferred from Level 1 to Level 2	$ 0	$ 0
Assets transferred from Level 2 to Level 1	0	0
Liabilities transferred from Level 1 to Level 2	0	0
Liabilities transferred from Level 2 to Level 1	0	0
Transfer of assets into (out of) level 3	0	0
Transfer of liabilities into (out of) level 3	0	0
Impairment losses	0	0
Accrued liabilities for legal and other contingencies	0	0
Restricted cash	$ 0	$ 0

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 7,677	$ 3,414
Less: Accumulated depreciation	(1,416)	(377)
Property, plant and equipment, net	6,261	3,037
Depreciation expense	1,117	326
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	5,988	2,121
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	96	18
Computer equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	37	22
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 1,556	$ 1,253

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expenses and Other Current Liabilities
Employee compensation and benefits	$ 4,077	$ 1,482
External research and development expenses	1,032	125
General and administrative professional service expenses	419	35
Other	485	115
Total accrued expenses and other current liabilities	$ 6,013	$ 1,757

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock - Redeemable Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands								7 Months Ended	12 Months Ended
	Mar. 29, 2021	Aug. 12, 2020	Jan. 22, 2020	Dec. 14, 2018	May 16, 2017	Mar. 03, 2017	Oct. 27, 2016	May 16, 2017	Dec. 31, 2021	Dec. 31, 2020
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Proceeds from issue of redeemable convertible preferred stock									$ 115,831	$ 49,842
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Shares issued					1,152,737	576,368	691,641
Purchase price (in dollars Per share}					$ 0.8675	$ 0.8675	$ 0.8675	$ 0.8675	$ 0.8675
Proceeds from issue of redeemable convertible preferred stock					$ 1,000	$ 500	$ 600
Series Seed redeemable convertible preferred stock \| Maximum
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Issuance costs								$ 100
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Shares issued		24,015,368	24,015,368	24,015,368						48,030,736
Purchase price (in dollars Per share}		$ 1.041	$ 1.041	$ 1.041					$ 1.041
Proceeds from issue of redeemable convertible preferred stock		$ 25,000	$ 25,000	$ 25,000
Aggregate shares issued				34,848,403
Issuance costs		$ 100
Shares issued in satisfaction of principal and interest on convertible notes				10,833,035
Convertible notes outstanding				$ 9,000
Shares issuable upon achievement of certain specified milestones				24,015,368
Series A Redeemable Convertible Preferred Stock \| Maximum
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Issuance costs			$ 100
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Shares issued	53,522,099								53,522,099
Purchase price (in dollars Per share}	$ 2.172								$ 2.172
Proceeds from issue of redeemable convertible preferred stock	$ 116,200
Issuance costs	$ 400

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Cash equivalents	$ 291,100	$ 39,000
Recurring
Assets:
Total	290,814	38,795
Recurring \| Money market funds
Assets:
Cash equivalents	290,814	38,795
Recurring \| Level 1
Assets:
Total	290,814	38,795
Recurring \| Level 1 \| Money market funds
Assets:
Cash equivalents	$ 290,814	$ 38,795

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock - Voting Rights (Details)	Dec. 31, 2021 Vote
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Number of directors entitled to be elected	3
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Number of directors entitled to be elected	3
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Number of directors entitled to be elected	1

Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock - Common Stock and Preferred Stock (Details)	Dec. 31, 2021 Vote $ / shares shares	Dec. 31, 2020 $ / shares shares
Redeemable Convertible Preferred Stock, Common Stock and Preferred Stock
Common Stock Authorized (shares)	150,000,000	113,259,306
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Number of votes \| Vote	1
Future awards	6,583,887	13,785,534
Preferred stock, shares authorized	10,000,000
Preferred stock, par value \| $ / shares	$ 0.0001
Preferred stock shares issued	0
Preferred stock shares outstanding	0

Stock Based Compensation (Details) - shares	1 Months Ended	12 Months Ended
Stock Based Compensation (Details) - shares	Oct. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future awards		6,583,887	13,785,534
2016 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future awards			360,306
Stock authorized for issuance		2,318,855	1,997,099
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares granted		0
Maximum term of options		10 years
Vesting period		4 years
Future awards		2,843,255
Stock authorized for issuance		3,986,270	0
Shares annual increase as percentage		4.00%
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future awards		278,762
2021 Employee Stock Purchase Plan \| ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for future issuance	557,524
Stock authorized for issuance	278,762	278,762
Shares annual increase as percentage	1.00%

Stock Based Compensation - Stock Option Valuation (Details) - Stock options	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Assumptions used to determine the fair value of stock options granted
Risk-free interest rate (as percentage)	1.15%	0.53%
Expected volatility (as percentage)	73.00%	75.00%
Expected term (in years)	6 years 3 days	5 years 11 months 26 days

Stock Based Compensation - Early Exercise of Unvested Stock Options (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Stock Based Compensation
Unvested shares related to early exercises of stock options	111,756	27,869
Unvested early exercises of stock options	$ 0.3	$ 0.1

Stock Based Compensation - Restricted Stock Awards (Details) - Restricted Stock Awards - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation
Vesting period	4 years
Shares
Unvested balance, at beginning of period (in shares)	11,537
Vested (in shares)	(11,537)
Unvested balance, at end of period (in shares)		11,537
Weighted- Average Grant -Date Fair Value
Weighted- Average Grant -Date Fair Value Unvested balance, at beginning of period (in dollars per share)	$ 0.007
Vested (in dollars per share)	$ 0.007
Weighted- Average Grant -Date Fair Value Unvested balance, at end of period (in dollars per share)		$ 0.007
Maximum
Additional information
Total fair value of restricted stock vested	$ 0.1	$ 0.1
Shares vesting after one year
Stock-based compensation
Vesting period	1 year
Vesting percentage	25.00%
Shares vesting after three year
Stock-based compensation
Vesting period	3 years

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Income tax benefits	$ 0.0	$ 0.0

Income Taxes - Reconciliation of U.S. federal statutory income tax rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory income tax rate	21.00%	21.00%
State income taxes, net of federal benefit	6.10%	6.20%
Federal and state research and development tax credits	3.90%	4.00%
Nondeductible items	(0.30%)	(0.20%)
Change in deferred tax asset valuation allowance	(30.70%)	(31.00%)
Effective income tax rate

Income Taxes - Operating loss carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Income tax benefits	$ 0	$ 0
Net operating loss carryforwards subject to expiration	3,200
Net operating loss carryforwards limited in usage	89,900
Uncertain tax position	0
Research and development tax credit carryforwards
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	15,700	$ 8,200
Federal
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	93,100
Tax credit carryforwards	2,300
State
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	88,000
Tax credit carryforwards	$ 1,200

Commitments and Contingencies (Details) $ in Millions	12 Months Ended
Commitments and Contingencies (Details) $ in Millions	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) ft²	Feb. 29, 2020 ft²	Mar. 31, 2019 ft²
Commitments and Contingencies
Rent expense	$ 6.0	$ 1.9
Office and laboratory space in Boston, Massachusetts
Commitments and Contingencies
Area of office and laboratory space \| ft²				26,235	7,981
Lease term	5 years 8 months 12 days
Office and laboratory space in Boston, Massachusetts \| Other non-current assets
Commitments and Contingencies
Security deposit	$ 0.5	$ 0.5
Additional office and laboratory space in Boston, Massachusetts
Commitments and Contingencies
Area of office and laboratory space \| ft²			8,631
Additional office and laboratory space in Boston, Massachusetts \| Other non-current assets
Commitments and Contingencies
Security deposit			$ 0.8

Commitments and Contingencies - Minimum aggregate future lease commitments (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Commitments and Contingencies
2022	$ 8,526
2023	8,384
Total future lease payments	$ 16,910

Commitments and Contingencies - License Agreement (Details) $ in Thousands	12 Months Ended			13 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2018 USD ($) installment item shares	Jun. 30, 2020 USD ($)
Commitments and Contingencies
Research and development expense	$ 35,926	$ 21,102
Expense relating to milestone obligation	0	0
License agreement with a third-party
Commitments and Contingencies
Upfront research fees			$ 400	$ 200
Number of installments \| installment			2
Value of assets purchased (in shares) \| shares			86,558
Value of assets purchased			$ 200
Potential milestone payment obligation			$ 2,600
Number of licensed products \| item			3
Patent costs	100	$ 100
License agreement with a third-party \| Maximum
Commitments and Contingencies
Annual license maintenance fee	$ 100

Net Loss per Share - Antidilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net Loss per Share
Antidilutive securities excluded from common stock	3,573,626	13,453,097
Redeemable convertible preferred stock
Net Loss per Share
Antidilutive securities excluded from common stock		11,788,435
Unvested restricted common stock
Net Loss per Share
Antidilutive securities excluded from common stock		11,537
Unvested shares from early exercises
Net Loss per Share
Antidilutive securities excluded from common stock	111,756	27,869
Stock options
Net Loss per Share
Antidilutive securities excluded from common stock	3,461,870	1,625,256