0000950170-22-003290 | 10-K | XBRL Viewer

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Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 200,825	$ 300,852
Marketable securities	175,746	44,462
Prepaid expenses and other current assets	5,821	3,773
Total current assets	382,392	349,087
Property and equipment, net	4,678	1,946
Right-of-use assets	36,282	0
Restricted cash and other assets	2,311	2,301
Total assets	425,663	353,334
Current liabilities:
Accounts payable	4,031	3,440
Accrued expenses and other current liabilities	20,799	7,527
Lease liabilities	3,893	0
Total current liabilities	28,723	10,967
Lease liability, net of current portion	28,743	0
Total liabilities	57,466	10,967
Commitments and contingencies (Note 13)
Stockholders’ equity
Preferred stock, $0.0001 par value; 10,000,000 shares authorized at December 31, 2021 and 2020	0	0
Common stock, $0.0001 par value; 200,000,000 shares authorized at December 31, 2021 and 2020, respectively; 51,607,522 and 45,446,903 shares issued and 51,569,381 and 45,076,574 shares outstanding at December 31, 2021 and 2020, respectively	6	5
Additional paid-in capital	596,934	421,572
Accumulated other comprehensive loss	(269)	(27)
Accumulated deficit	(228,474)	(79,183)
Total stockholders’ equity	368,197	342,367
Total liabilities and stockholders’ equity	$ 425,663	$ 353,334

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	51,607,522	45,446,903
Common stock, shares outstanding	51,569,381	45,076,574

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 121,308	$ 45,200
General and administrative	28,717	13,447
Total operating expenses	150,025	58,647
Loss from operations	(150,025)	(58,647)
Other (expense) income:
Interest income	742	56
Interest expense		(396)
Change in success fee obligation		450
Other income (expense), net	(8)
Total other (expense) income, net	734	(790)
Net loss	$ (149,291)	$ (59,437)
Net loss per share, basic and diluted	$ (2.93)	$ (4.13)
Weighted average common shares outstanding, basic and diluted	50,895,044	14,395,955
Comprehensive loss:
Net loss	$ (149,291)	$ (59,437)
Other comprehensive loss:
Unrealized losses on marketable securities	(242)	(27)
Comprehensive loss	$ (149,533)	$ (59,464)

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Convertible Preferred Stock	Convertible Preferred Stock Series A Convertible Preferred Stock	Convertible Preferred Stock Series B Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2019	$ 14,036						$ 1	$ 6,352		$ (19,746)
Beginning Balance, Shares at Dec. 31, 2019							2,586,535
Beginning Balance at Dec. 31, 2019				$ 27,429
Beginning Balance, Shares at Dec. 31, 2019				32,500,000
Issuance of Series A redeemable convertible preferred stock, net of issuance costs of $0.1 million		$ 19,467			$ 19,467
Issuance of Series A redeemable convertible preferred stock, net of issuance costs of $0.1 million, Shares					19,500,000
Issuance of stock, net of issuance costs	246,388		$ 115,319			$ 115,319	$ 1	246,387
Issuance of stock, net of issuance costs, Shares						41,159,724	14,089,314
Conversion of convertible preferred stock into common stock upon initial public offering				$ (162,215)			$ 3	162,212
Conversion of convertible preferred stock into common stock upon initial public offering, Shares				(93,159,724)			28,086,375
Exercise of stock options	30							30
Exercise of stock options, Shares							32,197
Stock-based compensation	6,591							6,591
Vesting of restricted shares							282,153
Unrealized gains on marketable securities	(27)								$ (27)
Net loss	(59,437)									(59,437)
Ending Balance at Dec. 31, 2020	342,367						$ 5	421,572	(27)	(79,183)
Ending Balance, Shares at Dec. 31, 2020							45,076,574
Issuance of stock, net of issuance costs	157,237						$ 1	157,236
Issuance of stock, net of issuance costs, Shares							6,000,000
Exercise of stock options	$ 584							584
Exercise of stock options, Shares	147,499						147,499
Stock-based compensation	$ 17,542							17,542
Vesting of restricted shares							251,808
Vesting of restricted stock units							93,500
Unrealized gains on marketable securities	(242)								(242)
Net loss	(149,291)									(149,291)
Ending Balance at Dec. 31, 2021	$ 368,197						$ 6	$ 596,934	$ (269)	$ (228,474)
Ending Balance, Shares at Dec. 31, 2021							51,569,381

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Common Stock
Stock issuance costs	$ 0.7	$ 2.6
Series A Redeemable Convertible Preferred Stock
Stock issuance costs		0.1
Series B Redeemable Convertible Preferred Stock Member
Stock issuance costs		$ 0.4

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (149,291)	$ (59,437)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	17,542	6,591
Depreciation and amortization expense	1,088	700
Amortization of debt discount		64
Amortization (accretion) of premium (discount) on marketable securities	2,580	12
Loss on sale of marketable securities	8
Non-cash lease expense	(746)
Change in success fee obligation		450
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,506)	(3,455)
Right-of-use assets	(2,940)
Accounts payable and other liabilities	13,702	8,567
Net cash used in operating activities	(119,563)	(46,508)
Cash flows from investing activities:
Purchases of property and equipment	(3,618)	(1,161)
Purchases of marketable securities	(236,721)	(44,500)
Maturities of marketable securities	98,010
Sales of marketable securities	4,437
Net cash used in investing activities	(137,892)	(45,661)
Cash flows from financing activities:
Proceeds from initial public offering of common stock, net of issuance costs		246,388
Proceeds from follow-on public offering of common stock, net of issuance costs	157,237
Settlement of success fee obligation		(450)
Proceeds from issuance of convertible preferred stock, net of issuance costs		134,786
Proceeds from issuance of debt, net of issuance costs		9,936
Repayment of debt		(10,000)
Proceeds from exercise of stock options	584	30
Net cash provided by financing activities	157,821	380,690
Net increase (decrease) in cash, cash equivalents and restricted cash	(99,634)	288,521
Cash, cash equivalents and restricted cash, beginning of year	303,153	14,632
Cash, cash equivalents and restricted cash, end of year	203,519	303,153
Supplemental cash flow information:
Cash paid for interest and taxes		328
Supplemental disclosure of non-cash investing and financing information:
Purchase of property and equipment in accounts payable	202
Right-of-use assets acquired under operating leases	34,228
Conversion of convertible preferred stock to common stock		$ 162,215

Nature of Business and Basis of Presentation

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Nature of Business and Basis of Presentation

1. Nature of Business and Basis of Presentation

Dyne Therapeutics, Inc. (the “Company”) is building a leading muscle disease company focused on advancing innovative life-transforming therapeutics for people living with genetically driven diseases. The Company was incorporated in Delaware on December 1, 2017 and has a principal place of business in Waltham, Massachusetts.

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval for its product candidates, fluctuations in operating results, compliance with government regulations, the ability to establish clinical- and commercial-scale manufacturing processes, the impact of the COVID-19 pandemic and the ability to secure additional capital to fund operations. Programs currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization of a product. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

On September 21, 2020, the Company completed its initial public offering (“IPO”) pursuant to which it issued and sold 14,089,314 shares of its common stock, including 1,837,736 shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $19.00 per share, resulting in net proceeds of $246.4 million, after deducting underwriting discounts and commissions and offering expenses. Upon the closing of the IPO, all of the Company’s then outstanding convertible preferred stock automatically converted into shares of common stock.

On January 25, 2021, the Company completed a follow-on public offering of common stock pursuant to which it issued and sold 6,000,000 shares of its common stock at a public offering price of $28.00 per share, resulting in net proceeds of $157.2 million, after deducting underwriting discounts and commissions and offering expenses.

The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations with proceeds from the sales of preferred stock and common stock, including the IPO completed in September 2020 and the follow-on offering completed in January 2021. The Company expects to continue to generate operating losses for the foreseeable future. The Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance of these consolidated financial statements.

To continue its development efforts, the Company will need to obtain substantial additional funding through public or private equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements in order to fund its research and development and ongoing operating expenses. The Company may not be able to obtain financing on acceptable terms, when needed or at all, and the Company may not be able to enter into collaborations, strategic alliances or licensing arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Any collaborations, strategic alliances or licensing arrangements may require the Company to relinquish rights to certain of its technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to the Company. If the Company is unable to obtain funding, the Company could be forced to delay, limit, reduce or eliminate some or all of its research and development programs, pipeline expansion or future commercialization efforts or grant rights to develop and market product candidates, which could adversely affect its business prospects. Although

management will continue to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations when needed or at all.

To date, the Company has not experienced material business disruptions, including with its vendors, as a result of the COVID-19 pandemic. The Company expects to continue to take actions as may be required or recommended by government authorities or as it determines are in the best interests of its employees and other business partners. The Company is continuing to monitor the potential impact of the pandemic, but cannot be certain what the overall impact will be on its business, financial condition, results of operations and prospects.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

The accompanying consolidated financial statements reflect the operations of the Company and the Company’s wholly-owned subsidiary, Dyne Therapeutics Securities Corporation. Intercompany balances and transactions have been eliminated in consolidation. The accompanying consolidated financial statements have been prepared in conformity with generally accepted accounting principles (“GAAP”) in the United States of America. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Use of estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual of research and development expenses and stock-based compensation expense. 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.

Concentrations of credit risk and of significant suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company believes the depository institutions in which the cash and cash equivalents are held are of high-credit quality. The Company maintains its cash equivalents in money market funds that invest in U.S. treasury securities and highly liquid investments maturing within 90 days from the date of purchase. The Company’s marketable securities as of December 31, 2021 consisted of commercial paper, certificates of deposit, corporate debt securities and U.S. treasury securities. The Company has adopted an investment policy that limits the amounts the Company may invest in the securities of any single issuer with the exclusion of the U.S. government. The Company has not experienced any credit losses.

The Company is dependent on a small number of third-party suppliers for its drug substance and drug product. In particular, the Company relies, and expects to continue to rely, on third-party suppliers for certain materials and components required for the development of its programs and future production of any product candidates it may develop for its programs. These programs could be adversely affected by a significant interruption in the supply process.

Cash and cash equivalents

Cash includes cash in readily available checking accounts and cash equivalents include money market funds that invest in U.S. treasury securities and all highly liquid investments maturing within 90 days from the date of purchase.

Restricted cash

Amounts included in restricted cash represent amounts pledged as collateral for letters of credit required for security deposits on the Company’s leased facilities. Restricted cash totaled $2.7 million and $2.3 million at 2021 and 2020, respectively. These amounts are classified as restricted cash on the Company’s consolidated balance sheets.

Marketable securities

The Company’s marketable securities consist of commercial paper, certificates of deposit, U.S. treasury notes and corporate debt securities and are classified as available-for-sale and are reported at fair value. Unrealized losses on available-for-sale debt securities are reported as a component of accumulated other comprehensive loss in stockholders’ equity. Realized gains and losses are based on the specific identification method and are included as a component of other income (expense), net in the consolidated statements of operations and comprehensive loss.

The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge to the statement of operations and comprehensive loss. No such adjustments were necessary during the periods presented.

Leases

Effective January 1, 2021, the Company adopted ASU 2016-02, Leases (Topic 842) (“ASC 842”), using the modified retrospective approach transition method as of the date of adoption. Under ASC 842, at the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances presented in the arrangement, including whether the Company controls the use of identified assets. The Company classifies leases with a term greater than one year as either operating or finance leases at the lease commencement date and records a right-of-use assets and current and non-current lease liabilities, as applicable on the balance sheet. The Company has elected not to recognize on the balance sheet leases with terms of one year or less, but payments are recognized as expense on a straight-line basis over the lease term. If a lease includes options to extend the lease term, the Company does not assume the option will be exercised in its initial lease term assessment unless there is reasonable certainty that the Company will renew based on an assessment of economic factors present as of the lease commencement date. The Company monitors its plans to renew its material lease each reporting period.

Lease liabilities and the corresponding right-of-use assets are recorded based on the present value of lease payments over the remaining lease term. The present value of future lease payments are discounted using the interest rate implicit in lease contracts if that rate is readily determinable; otherwise the Company utilizes its incremental borrowing rate (“IBR”), which reflects the fixed rate at which the Company could borrow on a collateralized basis over a similar term, the amount of the lease payments in a similar economic environment. After lease commencement and the establishment of a right-to-use asset and operating lease liability, lease expense is recorded on a straight-line basis over the lease term.

The Company enters into contracts that contain both lease and non-lease components. Non-lease components include costs that do not provide a right-to-use a leased asset but instead provide a service,

such as maintenance costs. The Company has elected to account for the lease and non-lease components together as a single component for all classes of underlying assets. Variable costs associated with the lease, such as maintenance and utilities, are not included in the measurement of right-to-use assets and lease liabilities but rather are expensed when the events determining the amount of variable consideration to be paid have occurred.

Property and equipment

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization 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
Furnitures and fixtures		5 years
Computer equipment		3 years
Leasehold improvements		Shorter of life of lease or 10 years

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 and amortization are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance which do not improve or extend the life of the respective assets are charged to expense as incurred.

Impairment of long-lived assets

Long-lived assets consist of property and equipment. The Company evaluates the recoverability of its long-lived assets when circumstances indicate that an event of impairment may have occurred. The Company recognizes an impairment loss only if the carrying amount of a long-lived asset is not recoverable based on its undiscounted future cash flows. Impairment is measured based on the difference between the carrying value of the related assets and the fair value of such assets. The Company has not recorded any impairment charges in the periods presented in these financial statements.

Segment information

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer (“CEO”). The CEO views the Company’s operations and manages the business as one operating segment.

Research and development costs

Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, facilities costs, laboratory supplies, depreciation and amortization, manufacturing expenses and external costs of vendors engaged to conduct clinical and preclinical development activities as well as the cost of licensing technology.

Upfront payments and milestone payments made for the licensing of technology are expensed as research and development expenses in the period in which they are incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are consumed or the services are performed.

Research and manufacturing contract costs and accruals

The Company has entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. The Company records accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research studies and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

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.

Income taxes

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 financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years 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 financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated 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 financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. 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.

Fair value measurements

Certain assets and liabilities are carried at fair value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

•

Level 1—Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities.

•

Level 2—Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following:

•

quoted prices for similar assets and liabilities in active markets;

•

quoted prices for identical or similar assets or liabilities in markets that are not active;

•

observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals); and

•

inputs that are derived principally from or corroborated by observable market data by correlation or other means.

•

Level 3—Unobservable inputs for the assets or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk).

Net loss per share

The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (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, the Company does not allocate loss to participating securities because they have no contractual obligation to share in the losses of the Company.

Basic net loss per share is computed by dividing the net income loss by the weighted average number of shares of common stock outstanding for the period. Diluted net loss is computed by adjusting net loss to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share is computed by dividing the diluted net loss by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents.

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.

Stock-based compensation

The Company accounts for stock option awards at fair value and measures fair value using the Black-Scholes option-pricing model as of the grant date. For restricted stock unit awards, the fair value is based on the closing price of the Company's common stock on the date of grant. Stock-based compensation costs are recognized as expense over the requisite service period, which is generally the vesting period, on a straight-line basis for all time-vested awards. For stock option awards with performance based vesting conditions and performance-based restricted stock unit awards, the fair value is calculated consistent with the above. The timing of expense recognition is based upon management’s estimation of the probability of the performance condition being achieved. Upon determination of the performance condition being deemed probable of achievement, expense is recognized over the remaining service period for performance-based awards. Forfeitures are recognized as they occur for all awards.

Success fee obligation

The Company’s loan and security agreement (the “Loan Agreement”) entered into in 2020 required the Company to pay a success fee of $0.5 million upon the occurrence of a specified liquidity event, as described in the Loan Agreement, which included the Company’s IPO. The liability was initially deemed immaterial upon entering into the Loan Agreement and was subsequently remeasured to fair value at each reporting date. Following the completion of the IPO, the success fee of $0.5 million was paid in September 2020 and no longer requires recognition.

Comprehensive loss

Comprehensive loss includes net loss as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive loss was unrealized gains (losses) on marketable securities.

Recently adopted accounting pronouncements

Prior to January 1, 2021, the Company accounted for leases under ASC 840, Leases (“ASC 840”). The Company recorded monthly rent expense on a straight-line basis, equal to the total of the payments due over the lease term, divided by the number of months of the lease term. The difference between rent expense recorded and the amount paid was charged to deferred rent.

Effective January 1, 2021, the Company adopted ASC 842, using the modified retrospective approach transition method as of the date of adoption. Under this method, financial statements for reporting periods after adoption are presented in accordance with ASC 842 and prior-period financial statements continue to be presented in accordance with ASC 840. Upon adoption, the Company recognized lease liabilities totaling $0.8 million and right-of-use assets totaling $0.7 million.

Cash, Cash Equivalents and Restricted Cash

12 Months Ended

Dec. 31, 2021

Restricted Cash and Cash Equivalents [Abstract]

Cash and Cash Equivalents Disclosure

3. Cash, Cash Equivalents and Restricted Cash

Amounts included in restricted cash represent amounts pledged as collateral for letters of credit required for security deposits on the Company’s leased facilities. Restricted cash totaled $2.7 million and $2.3 million at December 31, 2021 and December 31, 2020, respectively. These amounts are classified as a component of other current assets and as restricted cash on the Company’s consolidated balance sheets.

Cash, cash equivalents and restricted cash consisted of the following:


	December 31,		December 31,
(in thousands)	2021		2020
Cash and cash equivalents	$	200,825	$	300,852
Short term restricted cash included in other current assets		383		—
Restricted cash		2,311		2,301
Total	$	203,519	$	303,153

Fair Value Measurements

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

The following tables set forth by security type, marketable securities for the periods presented:


	As of December 31, 2021
(in thousands)		Amortized Cost		Unrealized Gains		Unrealized Losses			Total
Commercial paper			12,635		—		—			12,635
Corporate debt securities			138,207		3		(249	)		137,961
Certificates of deposit			4,490		—		—			4,490
U.S. treasury notes			20,683		—		(23	)		20,660
Total		$	176,015	$	3	$	(272	)	$	175,746


	As of December 31, 2020
(in thousands)		Amortized Cost		Unrealized Gains		Unrealized Losses			Total
Commercial paper			6,412		—		—			6,412
Certificates of deposit			1,504		—		—			1,504
Corporate debt securities			36,573		—		(27	)		36,546
Total		$	44,489	$	—	$	(27	)	$	44,462

The following tables set forth by level, within the fair value hierarchy (see Note 2), the assets carried at fair value on a recurring basis for the periods presented:


	Fair Value Measurements as of December 31, 2021
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	95,565	$	—	$	—	$	95,565
Corporate debt securities		—		1,844		—		1,844
Marketable securities
Commercial paper		12,635		—		—		12,635
Corporate debt securities		—		137,961		—		137,961
Certificates of deposit		—		4,490		—		4,490
U.S. treasury notes		20,660		—		—		20,660
Total	$	128,860	$	144,295	$	—	$	273,155


	Fair Value Measurements as of December 31, 2020
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	155,017		—		—	$	155,017
Commercial paper		2,999		—		—		2,999
Certificates of deposit		—		5,309		—		5,309
Marketable securities
Commercial paper		6,412		—		—		6,412
Certificates of deposit		—		1,504		—		1,504
Corporate debt securities		—		36,546		—		36,546
Total	$	164,428	$	43,359	$	—	$	207,787

The fair value of U.S. government money market funds and commercial paper were determined by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. Certificates of deposit and corporate debt securities were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy.

There were no transfers between Level 1, Level 2, or Level 3 during the periods presented.

The following table summarizes the scheduled maturity for the Company’s marketable securities for the periods presented:


(in thousands)	December 31,
	2021
Maturing in one year or less	$	140,919
Maturing after one year through two years		34,827
Maturing after two years		—
Total	$	175,746

Financial instruments not recorded at fair value

The carrying values of cash, cash equivalents, accounts payable and accrued expenses that are reported on the balance sheets approximate their fair value due to the short-term nature of these assets and liabilities.

- 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

Property and Equipment

12 Months Ended

Dec. 31, 2021

Property Plant And Equipment [Abstract]

Property and Equipment

. Property and Equipment

Property and equipment consisted of the following:


	December 31,
(in thousands)	2021			2020
Laboratory equipment	$	3,930		$	2,744
Office and computer equipment		1,271			78
Leasehold improvements		—			14
Construction in process		1,460			105
Property and equipment—at cost		6,661			2,941
Less accumulated depreciation and amortization		(1,983	)		(995	)
Property and equipment—net	$	4,678		$	1,946

Depreciation expense totaled $1.1 million and $0.7 million for the years ended December 31, 2021 and 2020, respectively.

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2021

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	December 31,
(in thousands)	2021		2020
Payroll and benefits	$	5,097	$	2,105
Consulting services		694		263
Legal services		184		325
Research and development		14,762		4,782
Facility costs		62		52
Total	$	20,799	$	7,527

Debt Financing

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Debt Financing

7. Debt Financing

On February 20, 2020, the Company entered into a Loan Agreement pursuant to which the lender made term loans to the Company in an aggregate principal amount of $10.0 million. Borrowings under the Loan Agreement were collateralized by substantially all of the Company’s assets, excluding intellectual property.

Interest on the outstanding loan balance accrued at a variable annual rate equal to the greater of (i) the lender’s prime rate plus 0.25% and (ii) 5.00%, and the Company was required to make interest-only payments on the loans on a monthly basis through August 2021. The outstanding borrowings were repaid in October 2020.

As part of the Loan Agreement, a success fee of $0.5 million was required in the event of a liquidation event, including an IPO. The success fee represented an embedded derivative which the Company bifurcated from the debt arrangement and carried at fair value. In September 2020, the Company completed its IPO and paid the success fee of $0.5 million.

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

Convertible Preferred Stock

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Convertible Preferred Stock

8. Convertible Preferred Stock

Since inception, the Company issued Series A convertible preferred stock (the “Series A Preferred Stock”) and Series B convertible preferred stock (the “Series B Preferred Stock”). Collectively the Series A Preferred Stock and the Series B Preferred Stock are referred to as the Preferred Stock.

Upon the closing of the IPO in September 2020, the Company’s Preferred Stock automatically converted into 28,086,375 shares of common stock.

Series A Preferred Stock

On November 29, 2018, the Company entered into the Series A Preferred Stock Purchase Agreement with its initial investors committing to purchase an aggregate of $50.0 million in shares of Series A Preferred Stock. At the initial closing, 12,500,000 shares of Series A Preferred Stock were issued by the Company at a purchase price of $1.00 per share, for gross cash proceeds of $7.5 million. Of the 12,500,000 shares issued, 5,000,000 shares were issued upon conversion of the then outstanding SAFEs, which had a fair value of $5.0 million. In April 2019, the Company issued an additional 20,000,000 shares of Series A Preferred Stock under the terms of the Series A Preferred Stock Purchase Agreement at a purchase price of $1.00 per share for total gross proceeds of $20.0 million. Issuance costs associated with each closing of the Series A Preferred Stock financing were $0.1 million. On March 18, 2020, the Company entered into a separate Series A Preferred Stock Purchase Agreement with an additional investor and issued 2,000,000 shares of Series A Preferred Stock at a purchase price $1.00 per share for gross cash proceeds of $2.0 million. In July 2020, the Company issued and sold 17,500,000 shares of Series A Preferred Stock at a price of $1.00 per share, for gross proceeds of $17.5 million.

Series B Preferred Stock

In August 2020, the Company issued and sold 41,159,724 shares of Series B Preferred Stock at a price of $2.81 per share for gross proceeds of $115.7 million.

The Preferred Stock had the followings rights and privileges:

Dividends

Holders of the Preferred Stock were entitled to receive non-cumulative dividends when, as and if declared by the Board. The Company did not declare dividends on any class of preferred or common stock.

Liquidation

In the event of any liquidation, dissolution, or winding-up of the Company, which would include the sale of the Company, the Preferred Stock was senior to common stock.

Voting

The holders of the Preferred Stock were entitled to the number of votes equal to the number of shares of common stock into which the shares of Preferred Stock held by each holder were then convertible.

Conversion

The holders of the Preferred Stock were able to convert, at any time, each share of Preferred Stock into shares of common stock at the stated conversion price.

Stock-based Compensation

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

9. Stock-Based Compensation

2018 Stock incentive plan

The Company’s 2018 Stock Incentive Plan (the “2018 Plan”) provided for the Company to sell or issue incentive stock options or nonqualified stock options, restricted stock, and other equity awards to employees, directors and consultants of the Company. The 2018 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors.

The total number of shares of common stock authorized under the 2018 Plan was 8,267,252 shares. Upon the effectiveness of the 2020 Plan, the Company ceased granting awards under the 2018 Plan, and the 1,928,487 shares of common stock remaining under the 2018 Plan became available for future issuance under the 2020 Plan.

2020 Stock incentive plan

In August 2020 the Company’s board of directors adopted and the Company’s stockholders approved the 2020 Plan (together with the 2018 Plan the “Plans”), which became effective on September 16, 2020. The 2020 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards to employees, directors, consultants and advisors of the Company. The 2020 Plan is administered by the Company’s board of directors or by a committee appointed by the board of directors. Upon the effectiveness of the 2020 Plan, the Company ceased granting awards under the 2018 Plan. The number of shares initially reserved for issuance under the 2020 Plan was 4,884,233. The number of shares of common stock reserved for issuance under the 2020 Plan automatically increases on the first day of each fiscal year, beginning with the fiscal year commencing on January 1, 2021 and continuing for each fiscal year until, and including the fiscal year commencing on, January 1, 2030, in an amount equal to the lower of (1) 5% of the shares of common stock outstanding on such date and (2) an amount determined by the Company’s board of directors. On January 1, 2021, 2,272,345 shares were added to the shares reserved for issuance under the 2020 Plan in the first of these annual increases. On January 1, 2022, 2,580,376 shares were added to the shares reserved for issuance under the 2020 Plan in the second of these annual increases.

As of December 31, 2021, 3,149,180 shares remained available for future issuance under the 2020 Plan.

2020 Employee Stock Purchase Plan

In August 2020 the Company’s board of directors adopted and the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), which became effective September 16, 2020. The 2020 ESPP is administered by the Company’s board of directors or by a committee appointed by the board of directors. The 2020 ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 488,414 shares of common stock. The number of shares of common stock reserved for issuance under the 2020 ESPP will automatically increase on the first day of each fiscal year, beginning with the fiscal year commencing on January 1, 2021 and continuing for each fiscal year until, and including the fiscal year commencing on, January 1, 2030, in an amount equal to the lowest of (1) 1,953,656 shares of common stock, (2) 1% of the shares of common stock outstanding on such date, and (3) an amount determined by the board of directors. As of December 31, 2021, no offering periods have commenced under the 2020 ESPP and 488,414 shares remained available for issuance.

Stock option valuation

The Company typically grants stock options at exercise prices deemed by the Board to be equal to the fair value of the common stock at the time of grant. In the periods prior to the IPO, the fair value of the common stock was determined by the Board at each measurement date based on a variety of different factors, including the results obtained from independent third-party appraisals, the Company’s financial position and historical financial performance, the status of development of the Company’s programs, the current climate in the marketplace, the illiquid nature of the common stock, the effect of the rights and preferences of the preferred stockholders, and the prospects of a liquidity event, among others. In the periods following the IPO, the fair value is determined based upon the quoted price of the Company’s common stock.

The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company historically has been a private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. For options with

service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

The assumptions that the Company used to determine the grant-date fair value of options granted were as follows:


	Year Ended December 31,
	2021		2020
Expected volatility	74%		75%
Risk-free interest rate	0.82% — 1.34%		0.31% — 1.67%
Expected term (in years)	6			6
Expected dividend yield		—		—

Stock option activity

The following table summarizes the option activity:


(in thousands, except share and per share data)	Options			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value
Outstanding January 1, 2021		6,421,589		$	6.97		9.5	$	90,112
Granted		2,240,816			15.84
Exercised		(147,499	)		3.96
Canceled		(547,156	)		9.44
Outstanding December 31, 2021		7,967,750		$	9.35		8.7	$	36,946
Options exercisable— December 31, 2021		1,872,885		$	6.13		8.7	$	13,227
Options vested or expected to vest— December 31, 2021		7,967,750		$	9.35		8.2	$	36,946

The intrinsic value of options exercised for the years ended December 31, 2021 and 2020 totaled $1.9 million and $0.2 million, respectively. The weighted-average grant date fair value of the options granted during the years ended December 31, 2021 and 2020 was $10.23 per share and $4.50 per share, respectively. As of December 31, 2021 there was $30.2 million of unrecognized compensation expense, which the Company expects to recognize over a weighted-average period of 2.5 years. In December 2021, the Company recognized compensation cost of $1.8 million related to stock options with performance-based vesting conditions for which performance was deemed probable.

Restricted stock units

A restricted stock unit (“RSU”) represents the right to receive one share of common stock upon vesting of the RSU. The Company grants RSUs with service conditions that vest in either four equal annual installments or sixteen equal quarterly installments provided that the employee remains employed with the Company. The Company also grants RSUs with performance conditions that vest upon the achievement of specified milestones. The fair value of each RSU is based on the closing price of the Company’s common stock on the date of grant. A summary of the Company’s RSU activity and related information for the 2020 Plan for the year ended December 31, 2021 is as follows:


	Number of Shares Underlying RSUs			Weighted Average Grant Date Fair Value
Issued and unvested as of January 1, 2021		403,355		$	23.60
Granted		793,629			14.76
Vested		(93,500	)		23.69
Forfeited		(46,500	)		23.35
Issued and unvested as of December 31, 2021		1,056,984		$	16.99

The weighted average grant date fair value of RSUs granted during the year ended December 31, 2020 was $23.60. As of December 31, 2021, there was $14.6 million of unrecognized compensation costs related to unvested RSUs, which are expected to be recognized over a weighted-average period of 3.4 years. In December 2021, the Company recognized compensation cost of $0.5 million related to RSUs with performance-based vesting conditions for which performance was deemed probable.

Restricted common stock

During the year ended December 31, 2018, the Company granted restricted common stock with service-based vesting conditions. Shares of unvested restricted common stock may not be sold or transferred by the holder. These restrictions lapse according to the time-based vesting conditions of each award. The grant date fair value of these shares was immaterial. The following table summarizes the Company’s restricted common stock award activity for the year ended December 31, 2021:


	Number of Restricted Shares
Issued and unvested as of January 1, 2021		370,329
Vested		(251,808	)
Forfeited		(80,380	)
Issued and unvested as of December 31, 2021		38,141

The Company recorded stock-based compensation expense in the following expense categories of its statements of operations:


	Year Ended December 31,
(in thousands)	2021		2020
Research and development	$	7,328	$	2,699
General and administrative		10,214		3,892
Total	$	17,542	$	6,591

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

There is no provision for income taxes because the Company has historically incurred net operating losses and maintains a full valuation allowance against its deferred tax assets.

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 income tax expense at statutory rate		21	%		21	%
State taxes—net of federal benefit		5			5
Change in fair value of preferred stock tranche obligations		—			—
Permanent differences and other		(1	)		—
Federal & state R&D credits		2			1
Increase in valuation allowance		(27	)		(27	)
Effective income tax rate		0	%		0	%

Significant components of the Company’s net deferred tax assets at December 31, 2021 and 2020 are as follows:


	Year Ended December 31,
(in thousands)	2021			2020
Deferred tax assets:
Stock-based compensation	$	2,333		$	1,349
Net operating loss carryforwards		51,500			18,858
Credit carryforwards		4,799			1,155
Fixed assets		705			—
Accrued expenses		5,205			580
Lease liability		8,916			—
Total deferred tax assets		73,458			21,942
Valuation allowance		(63,546	)		(21,899	)
Total net deferred tax assets		9,912			43
Deferred tax liabilities:
Fixed assets		—			(43	)
Right of use asset		(9,912	)		—
Total deferred tax liability		(9,912	)		(43	)
Total deferred tax assets (liabilities)	$	—		$	—

As of December 31, 2021, the Company had federal and state net operating loss carryforwards of $188.7 million and $188.0 million, respectively. The federal net operating loss carryforwards are indefinite lived and the state net operating loss carryforwards begin to expire in 2038. As of December 31, 2021, the Company also had federal and state research and development tax credit carryforwards $3.6 million and $1.6 million, respectively, which begin to expire in 2039 and 2033, respectively.

Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 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. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period. The Company completed a Section 382 study of transactions in its stock through January 25, 2021 and concluded that it had experienced ownership changes since inception that it believes under Section 382 and 383 of the Code will result in limitations on its ability to use certain pre-change NOLs and credits. In addition, the Company may experience subsequent ownership changes as a result of future equity offerings or other changes in the ownership of its stock, some of which are beyond the Company's control. As a result, the amount of the NOLs and tax credit carryforwards presented in these consolidated financial statements could be limited. Similar provisions of state tax law may also apply to limit the use of accumulated state tax attributes.

The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally 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 and its lack of commercialization of any products or generation of any revenue from product sales since inception and concluded that it is more likely than not that the Company will not recognize the benefits of its federal and state 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 increase in the valuation allowance for deferred tax assets during the years ended December 31, 2021 and 2020 related primarily to the increase in net operating loss carryforwards.

Changes in the valuation allowance were as follows:


	Year Ended December 31,
	2021		2020
Valuation allowance at the beginning of year	$	21,899	$	5,607
Decreases recorded as benefit to income tax provision		—		—
Increases recorded to income tax provision		41,647		16,292
Valuation allowance at the end of year	$	63,546	$	21,899

The Company’s policy is to record estimated interest and penalties related to uncertain tax positions in income tax expense. The Company has no amounts recorded for any unrecognized tax positions, accrued interest or penalties as of December 31, 2021 and 2020.

The Company files 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 U.S. federal and state jurisdictions, where applicable. There are currently no pending tax examinations. The Company’s tax returns are open under statute from 2018 to the present.

- 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
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-Name Accounting Standards Codification
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-SubTopic 10
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Net Loss Per Share

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net Loss per Share

. Net Loss per Share

Basic and diluted net loss per share was calculated as follows:


	Year Ended December 31,
(in thousands, except share and per share data)	2021			2020
Numerator:
Net loss	$	(149,291	)	$	(59,437	)
Denominator:
Weighted-average common shares outstanding—basic and diluted		50,895,044			14,395,955
Net loss per share—basic and diluted	$	(2.93	)	$	(4.13	)

The following potentially dilutive common stock equivalents, presented based on amounts outstanding at each period end, were excluded from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:


	Year Ended December 31,
	2021		2020
Options to purchase common stock		7,967,750		6,421,589
Unvested restricted common stock		38,141		370,329
Unvested restricted stock units		1,056,984		403,355
Total		9,062,875		7,195,273

Leases

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Leases

12. Leases

In May 2019, the Company entered into a sublease agreement for laboratory and office space in Waltham, Massachusetts. The term of the sublease commenced on July 1, 2019 and expired on December 31, 2021.

In December 2020, the Company entered into a lease agreement, (the “Lease”), pursuant to which the Company leases 68,187 square feet of office and laboratory space located in Waltham, Massachusetts (the “Premises”). The Lease has a term of eight years and six months and the Company gained access to the Premises in September 2021. The Company’s obligation for the payment of base rent for the Premises begins in April 2022, and will be $0.4 million per month, increasing up to $0.5 million during the term of the Lease. The Company has two options to extend the term of the Lease, each for a period of an additional five years.

Rent expense for the years ended December 31, 2021 and 2020 totaled $2.1 million and $0.8 million, respectively.

Summary of lease costs

The Company did not have any finance leases as of December 31, 2021.

The components of lease cost under ASC 842 for the leases were as follows:


	Year Ended December 31,
(in thousands)	2021
Operating lease cost	$	2,126
Short term lease cost		—
Variable lease cost		573
Total lease cost	$	2,699

Supplemental disclosure of cash flow information under ASC 842 for the leases were as follows:


	Year Ended December 31,
(in thousands)	2021
Operating cash payments for operating leases	$	800

The weighted-average remaining lease term and discount rate for the leases were as follows:


(in thousands)	As of December 31, 2021
Weighted-average remaining lease term - operating leases	8.25 years
Weighted-average discount rate - operating leases		5.80	%

Future minimum lease payments under the non-cancelable operating leases consisted of the following as of December 31, 2021:


Year Ending December 31,	(in thousands)
2022	$	4,008
2023		4,706
2024		4,847
2025		4,993
2026		5,143
Thereafter		17,787
Total future minimum lease payments		41,484
Less: imputed interest		(8,848	)
Present value of lease liabilities	$	32,636

Included in the condensed consolidated balance sheet (in thousands)	December 31, 2021
Lease liability	$	3,893
Lease liability, net of current portion		28,743
Total lease liability	$	32,636

Future minimum lease payments under non-cancelable operating leases under ASC 840 consisted of the following as of December 31, 2020:


Year Ending December 31,	(in thousands)
2021	$	800
2022		3,452
2023		4,706
2024		4,847
2025		4,993
Thereafter		22,930
Total	$	41,728

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

13. Commitments and Contingencies

Legal proceedings

The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to any such legal proceedings.

Other contractual obligations

The Company enters into contracts in the normal course of business with third parties for preclinical research studies, clinical trials and testing and manufacturing services. These contracts typically do not contain minimum purchase commitments and are generally cancelable by the Company upon written notice. Payments due upon cancellation consist of payments for services provided or expenses incurred, including noncancelable obligations of the service providers, up to the date of cancellation and in the case of certain arrangements may include non-cancelable fees.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Use of Estimates

Use of estimates

Concentrations of Credit Risk and of Significant Suppliers

Concentrations of credit risk and of significant suppliers

Cash and Cash Equivalents

Cash and cash equivalents

Restricted Cash

Restricted cash

Marketable Securities

Marketable securities

Leases

The Company enters into contracts that contain both lease and non-lease components. Non-lease components include costs that do not provide a right-to-use a leased asset but instead provide a service,

Property and Equipment

Property and equipment


		Estimated Useful Life
Laboratory equipment		5 years
Furnitures and fixtures		5 years
Computer equipment		3 years
Leasehold improvements		Shorter of life of lease or 10 years

Impairment of Long-Lived Assets

Impairment of long-lived assets

Segment Information

Segment information

Research and Development Costs

Research and development costs

Research and Manufacturing Contract Costs and Accruals

Research and manufacturing contract costs and accruals

Patent Costs

Patent costs

Income Taxes

Income taxes

Fair Value Measurements

Fair value measurements

•

Level 1—Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities.

•

quoted prices for similar assets and liabilities in active markets;

•

quoted prices for identical or similar assets or liabilities in markets that are not active;

•

observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals); and

•

inputs that are derived principally from or corroborated by observable market data by correlation or other means.

•

Net Loss Per Share

Net loss per share

Redeemable Convertible Preferred Stock

Redeemable convertible preferred stock

Stock-Based Compensation

Stock-based compensation

Success Fee Obligation

Success fee obligation

Comprehensive Loss

Comprehensive loss

Recently adopted accounting pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule Of Property Plant And Equipment Estimated Useful Lives

Depreciation and amortization 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
Furnitures and fixtures		5 years
Computer equipment		3 years
Leasehold improvements		Shorter of life of lease or 10 years

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Marketable Securities by Security Type

The following tables set forth by security type, marketable securities for the periods presented:


	As of December 31, 2021
(in thousands)		Amortized Cost		Unrealized Gains		Unrealized Losses			Total
Commercial paper			12,635		—		—			12,635
Corporate debt securities			138,207		3		(249	)		137,961
Certificates of deposit			4,490		—		—			4,490
U.S. treasury notes			20,683		—		(23	)		20,660
Total		$	176,015	$	3	$	(272	)	$	175,746


	As of December 31, 2020
(in thousands)		Amortized Cost		Unrealized Gains		Unrealized Losses			Total
Commercial paper			6,412		—		—			6,412
Certificates of deposit			1,504		—		—			1,504
Corporate debt securities			36,573		—		(27	)		36,546
Total		$	44,489	$	—	$	(27	)	$	44,462

Summary of Assets Carried at Fair Value on Recurring Basis

The following tables set forth by level, within the fair value hierarchy (see Note 2), the assets carried at fair value on a recurring basis for the periods presented:


	Fair Value Measurements as of December 31, 2021
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	95,565	$	—	$	—	$	95,565
Corporate debt securities		—		1,844		—		1,844
Marketable securities
Commercial paper		12,635		—		—		12,635
Corporate debt securities		—		137,961		—		137,961
Certificates of deposit		—		4,490		—		4,490
U.S. treasury notes		20,660		—		—		20,660
Total	$	128,860	$	144,295	$	—	$	273,155


	Fair Value Measurements as of December 31, 2020
(in thousands)	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	155,017		—		—	$	155,017
Commercial paper		2,999		—		—		2,999
Certificates of deposit		—		5,309		—		5,309
Marketable securities
Commercial paper		6,412		—		—		6,412
Certificates of deposit		—		1,504		—		1,504
Corporate debt securities		—		36,546		—		36,546
Total	$	164,428	$	43,359	$	—	$	207,787

Summary of Scheduled Maturity for Marketable Securities

The following table summarizes the scheduled maturity for the Company’s marketable securities for the periods presented:


(in thousands)	December 31,
	2021
Maturing in one year or less	$	140,919
Maturing after one year through two years		34,827
Maturing after two years		—
Total	$	175,746

Summary of Cash, Cash Equivalents and Restricted Cash (Tables)

12 Months Ended

Dec. 31, 2021

Restricted Cash and Cash Equivalents [Abstract]

Restrictions on Cash and Cash Equivalents

Cash, cash equivalents and restricted cash consisted of the following:


	December 31,		December 31,
(in thousands)	2021		2020
Cash and cash equivalents	$	200,825	$	300,852
Short term restricted cash included in other current assets		383		—
Restricted cash		2,311		2,301
Total	$	203,519	$	303,153

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2021

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consisted of the following:


	December 31,
(in thousands)	2021			2020
Laboratory equipment	$	3,930		$	2,744
Office and computer equipment		1,271			78
Leasehold improvements		—			14
Construction in process		1,460			105
Property and equipment—at cost		6,661			2,941
Less accumulated depreciation and amortization		(1,983	)		(995	)
Property and equipment—net	$	4,678		$	1,946

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	December 31,
(in thousands)	2021		2020
Payroll and benefits	$	5,097	$	2,105
Consulting services		694		263
Legal services		184		325
Research and development		14,762		4,782
Facility costs		62		52
Total	$	20,799	$	7,527

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Assumptions Used to Determine Grant-Date Fair Value of Options Granted

The assumptions that the Company used to determine the grant-date fair value of options granted were as follows:


	Year Ended December 31,
	2021		2020
Expected volatility	74%		75%
Risk-free interest rate	0.82% — 1.34%		0.31% — 1.67%
Expected term (in years)	6			6
Expected dividend yield		—		—

Summary of Stock Option Activity and Related Information

The following table summarizes the option activity:


(in thousands, except share and per share data)	Options			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value
Outstanding January 1, 2021		6,421,589		$	6.97		9.5	$	90,112
Granted		2,240,816			15.84
Exercised		(147,499	)		3.96
Canceled		(547,156	)		9.44
Outstanding December 31, 2021		7,967,750		$	9.35		8.7	$	36,946
Options exercisable— December 31, 2021		1,872,885		$	6.13		8.7	$	13,227
Options vested or expected to vest— December 31, 2021		7,967,750		$	9.35		8.2	$	36,946

Summary of RSU Activity

A summary of the Company’s RSU activity and related information for the 2020 Plan for the year ended December 31, 2021 is as follows:


	Number of Shares Underlying RSUs			Weighted Average Grant Date Fair Value
Issued and unvested as of January 1, 2021		403,355		$	23.60
Granted		793,629			14.76
Vested		(93,500	)		23.69
Forfeited		(46,500	)		23.35
Issued and unvested as of December 31, 2021		1,056,984		$	16.99

Summary of Restricted Common Stock Award Activity

The following table summarizes the Company’s restricted common stock award activity for the year ended December 31, 2021:


	Number of Restricted Shares
Issued and unvested as of January 1, 2021		370,329
Vested		(251,808	)
Forfeited		(80,380	)
Issued and unvested as of December 31, 2021		38,141

Summary of Stock-based Compensation Expense

The Company recorded stock-based compensation expense in the following expense categories of its statements of operations:


	Year Ended December 31,
(in thousands)	2021		2020
Research and development	$	7,328	$	2,699
General and administrative		10,214		3,892
Total	$	17,542	$	6,591

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation

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 income tax expense at statutory rate		21	%		21	%
State taxes—net of federal benefit		5			5
Change in fair value of preferred stock tranche obligations		—			—
Permanent differences and other		(1	)		—
Federal & state R&D credits		2			1
Increase in valuation allowance		(27	)		(27	)
Effective income tax rate		0	%		0	%

Schedule of Deferred Tax Assets and Liabilities

Significant components of the Company’s net deferred tax assets at December 31, 2021 and 2020 are as follows:


	Year Ended December 31,
(in thousands)	2021			2020
Deferred tax assets:
Stock-based compensation	$	2,333		$	1,349
Net operating loss carryforwards		51,500			18,858
Credit carryforwards		4,799			1,155
Fixed assets		705			—
Accrued expenses		5,205			580
Lease liability		8,916			—
Total deferred tax assets		73,458			21,942
Valuation allowance		(63,546	)		(21,899	)
Total net deferred tax assets		9,912			43
Deferred tax liabilities:
Fixed assets		—			(43	)
Right of use asset		(9,912	)		—
Total deferred tax liability		(9,912	)		(43	)
Total deferred tax assets (liabilities)	$	—		$	—

Schedule of Changes in Valuation Allowance

Changes in the valuation allowance were as follows:


	Year Ended December 31,
	2021		2020
Valuation allowance at the beginning of year	$	21,899	$	5,607
Decreases recorded as benefit to income tax provision		—		—
Increases recorded to income tax provision		41,647		16,292
Valuation allowance at the end of year	$	63,546	$	21,899

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

Basic and diluted net loss per share was calculated as follows:


	Year Ended December 31,
(in thousands, except share and per share data)	2021			2020
Numerator:
Net loss	$	(149,291	)	$	(59,437	)
Denominator:
Weighted-average common shares outstanding—basic and diluted		50,895,044			14,395,955
Net loss per share—basic and diluted	$	(2.93	)	$	(4.13	)

Potential Dilutive Securities Excluded From Calculation Of Net Loss Per Share


	Year Ended December 31,
	2021		2020
Options to purchase common stock		7,967,750		6,421,589
Unvested restricted common stock		38,141		370,329
Unvested restricted stock units		1,056,984		403,355
Total		9,062,875		7,195,273

Leases (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Components of Lease Cost for the Sublease

The components of lease cost under ASC 842 for the leases were as follows:


	Year Ended December 31,
(in thousands)	2021
Operating lease cost	$	2,126
Short term lease cost		—
Variable lease cost		573
Total lease cost	$	2,699

Supplemental Disclosure of Cash Flow Information Related to Leases for the Sublease

Supplemental disclosure of cash flow information under ASC 842 for the leases were as follows:


	Year Ended December 31,
(in thousands)	2021
Operating cash payments for operating leases	$	800

Schedule of Weighted Average Remaining Lease Term and Discount Rate for the Sublease

The weighted-average remaining lease term and discount rate for the leases were as follows:


(in thousands)	As of December 31, 2021
Weighted-average remaining lease term - operating leases	8.25 years
Weighted-average discount rate - operating leases		5.80	%

Schedule of Future Minimum Lease Payments under Non-Cancelable Operating Leases

Future minimum lease payments under the non-cancelable operating leases consisted of the following as of December 31, 2021:


Year Ending December 31,	(in thousands)
2022	$	4,008
2023		4,706
2024		4,847
2025		4,993
2026		5,143
Thereafter		17,787
Total future minimum lease payments		41,484
Less: imputed interest		(8,848	)
Present value of lease liabilities	$	32,636

Included in the condensed consolidated balance sheet (in thousands)	December 31, 2021
Lease liability	$	3,893
Lease liability, net of current portion		28,743
Total lease liability	$	32,636

Future minimum lease payments under non-cancelable operating leases under ASC 840 consisted of the following as of December 31, 2020:


Year Ending December 31,	(in thousands)
2021	$	800
2022		3,452
2023		4,706
2024		4,847
2025		4,993
Thereafter		22,930
Total	$	41,728

Nature of Business and Basis of Presentation - Additional Information (Details) - Common Stock - USD ($) $ / shares in Units, $ in Millions	Jan. 25, 2021	Sep. 21, 2020
Initial Public Offering
Nature Of Business And Basis Of Presentation [Line Items]
Number of shares issued and sold		14,089,314
Underwriters option to purchase additional shares		1,837,736
Public offering price		$ 19.00
Net proceeds from issuance of common stock		$ 246.4
Follow-on Public Offering
Nature Of Business And Basis Of Presentation [Line Items]
Number of shares issued and sold	6,000,000
Public offering price	$ 28.00
Net proceeds from issuance of common stock	$ 157.2

Summary of Significant Accounting Policies - Additional Information (Details)	1 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($)	Dec. 31, 2021 USD ($) Segment	Dec. 31, 2020 USD ($)	Jan. 01, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalent maturity period		90 days
Restricted cash		$ 2,700,000	$ 2,300,000
Impairment charges		$ 0
Number of operating segment \| Segment		1
Success fee paid	$ 500,000
Lease liabilities		$ 32,636,000		$ 800,000
Right-of-use assets		$ 36,282,000	0	$ 700,000
Loan Agreement \| Pacific Western Bank
Summary Of Significant Accounting Policies [Line Items]
Success fee paid			$ 500,000

Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Furnitures and Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, useful life	Shorter of life of lease or 10 years

Summary of Cash, Cash Equivalents and Restricted Cash -Additional information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 200,825	$ 300,852
Short term restricted cash included in other current assets	383	0
Restricted cash	2,311	2,301
Total	$ 203,519	$ 303,153

Cash, Cash Equivalents and Restricted Cash (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents [Abstract]
Cash and cash equivalent maturity period	90 days
Restricted cash	$ 2.7	$ 2.3

Fair Value Measurements - Summary of Marketable Securities by Security Type (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 176,015	$ 44,489
Unrealized Gains	3
Unrealized Losses	(272)	(27)
Total	175,746	44,462
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	12,635	6,412
Total	12,635	6,412
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,490	1,504
Total	4,490	1,504
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	138,207	36,573
Unrealized Gains	3
Unrealized Losses	(249)	(27)
Total	137,961	$ 36,546
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	20,683
Unrealized Losses	(23)
Total	$ 20,660

Fair Value Measurements - Summary of Assets Carried at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Total	$ 273,155	$ 207,787
Level 1
Assets:
Total	128,860	164,428
Level 2
Assets:
Total	144,295	43,359
Cash Equivalents \| Corporate Debt Securities
Assets:
Total	1,844
Cash Equivalents \| Money Market Funds
Assets:
Total	95,565	155,017
Cash Equivalents \| Commercial Paper
Assets:
Total		2,999
Cash Equivalents \| Certificates of Deposit
Assets:
Total		5,309
Cash Equivalents \| Level 1 \| Corporate Debt Securities
Assets:
Total	0
Cash Equivalents \| Level 1 \| Money Market Funds
Assets:
Total	95,565	155,017
Cash Equivalents \| Level 1 \| Commercial Paper
Assets:
Total		2,999
Cash Equivalents \| Level 2 \| Corporate Debt Securities
Assets:
Total	1,844
Cash Equivalents \| Level 2 \| Certificates of Deposit
Assets:
Total		5,309
Marketable Securities \| Corporate Debt Securities
Assets:
Total	137,961	36,546
Marketable Securities \| U.S. Treasury Notes
Assets:
Total	20,660
Marketable Securities \| Commercial Paper
Assets:
Total	12,635	6,412
Marketable Securities \| Certificates of Deposit
Assets:
Total	4,490	1,504
Marketable Securities \| Level 1 \| U.S. Treasury Notes
Assets:
Total	20,660
Marketable Securities \| Level 1 \| Commercial Paper
Assets:
Total	12,635	6,412
Marketable Securities \| Level 2 \| Corporate Debt Securities
Assets:
Total	137,961	36,546
Marketable Securities \| Level 2 \| Certificates of Deposit
Assets:
Total	$ 4,490	$ 1,504

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair value assets, transfers among level 1, level 2 or level 3	$ 0	$ 0

Fair Value Measurements - Summary of Scheduled Maturity for Marketable Securities (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Fair Value Disclosures [Abstract]
Maturing in one year or less	$ 140,919
Maturing after one year through two years	34,827
Maturing after two years	0
Total	$ 175,746

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment—at cost	$ 6,661	$ 2,941
Less accumulated depreciation and amortization	(1,983)	(995)
Property and equipment—net	4,678	1,946
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment—at cost	3,930	2,744
Office and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment—at cost	1,271	78
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment—at cost	0	14
Construction in Process
Property Plant And Equipment [Line Items]
Property and equipment—at cost	$ 1,460	$ 105

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 1,088	$ 700

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Payroll and benefits	$ 5,097	$ 2,105
Consulting services	694	263
Legal services	184	325
Research and development	14,762	4,782
Facility costs	62	52
Total	$ 20,799	$ 7,527

Debt Financing - Additional Information (Details) - Term Loan - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Feb. 20, 2020	Sep. 30, 2020	Dec. 31, 2021
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity under loan agreement	$ 10.0
Credit facility, interest rate description			Interest on the outstanding loan balance accrued at a variable annual rate equal to the greater of (i) the lender’s prime rate plus 0.25% and (ii) 5.00%, and the Company was required to make interest-only payments on the loans on a monthly basis through August 2021.
Debt instrument, frequency of periodic payment of interest			interest-only payments on the loans on a monthly basis
Credit facility, variable interest rate spread	0.25%
Credit facility, interest rate during period	5.00%
Success fee required to pay in the event of liquidation, including IPO	$ 0.5
Success fee paid after IPO		$ 0.5

Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended		12 Months Ended
	Jul. 31, 2020	Mar. 18, 2020	Nov. 29, 2018	Aug. 31, 2020	Apr. 30, 2019	Dec. 31, 2021	Dec. 31, 2020
Temporary Equity [Line Items]
Proceeds from issuance of convertible preferred stock, net of issuance costs							$ 134,786
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Purchase of share			$ 50,000
Shares issued	17,500,000	2,000,000	12,500,000		20,000,000
Stock Issued upon conversion			5,000,000
Convertible preferred stock, price per share	$ 1.00	$ 1.00	$ 1.00		$ 1.00
Proceeds from issuance of convertible preferred stock, net of issuance costs	$ 17,500	$ 2,000	$ 7,500		$ 20,000
Stock issued upon conversion, fair value			$ 5,000
Issuance costs					$ 100
Sale of stock	17,500,000
Series B Convertible Preferred Stock
Temporary Equity [Line Items]
Shares issued				41,159,724
Convertible preferred stock, price per share				$ 2.81
Proceeds from issuance of convertible preferred stock, net of issuance costs				$ 115,700
Common Stock
Temporary Equity [Line Items]
Convertible preferred stock, shares issued upon conversion						28,086,375
Shares issued						6,000,000	14,089,314
Stock Issued upon conversion							28,086,375
Stock issued upon conversion, fair value							$ 3

Equity - Additional Information (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.0001

Stock-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Millions		1 Months Ended	12 Months Ended
	Sep. 16, 2020 shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) Installment $ / shares shares	Dec. 31, 2020 USD ($) $ / shares	Jan. 01, 2022 shares	Jan. 01, 2021 shares	Sep. 15, 2020 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised \| $			$ 1.9	$ 0.2
Weighted-average grant date fair value of options granted \| $ / shares			$ 10.23	$ 4.50
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense \| $		$ 30.2	$ 30.2
Unrecognized share based compensation expense, recognition period			2 years 6 months
Recognized compensation cost related to unvested stock-based awards with performance-based vesting conditions for which performance conditions deemed probable \| $		1.8
Restricted Stock Units ("RSUs")
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted \| $ / shares				$ 23.60
Unrecognized compensation expense \| $		14.6	$ 14.6
Unrecognized share based compensation expense, recognition period			3 years 4 months 24 days
Recognized compensation cost related to unvested stock-based awards with performance-based vesting conditions for which performance conditions deemed probable \| $		$ 0.5
Number of share of common stock receivable upon vesting			1
2020 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total number of shares of common stock authorized	488,414
Number of shares available for future issuance		488,414	488,414
Percentage of outstanding shares increased annually under the plan	1.00%
Increase in common stock reserved for future issuance	1,953,656
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total number of shares of common stock authorized							8,267,252
Number of shares available for future issuance							1,928,487
2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance		3,149,180	3,149,180
Number of shares initially reserved for issuance	4,884,233				2,580,376	2,272,345
Percentage of outstanding shares increased annually under the plan	5.00%
2020 Plan \| Restricted Stock Units ("RSUs")
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted \| $ / shares			$ 14.76
Share-based Compensation Arrangement By Share-based Payment Award Grant Service Conditions to Vest Number of Annual Installments \| Installment			4
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights			The Company grants RSUs with service conditions that vest in either four equal annual installments or sixteen equal quarterly installments provided that the employee remains employed with the Company. The Company also grants RSUs with performance conditions that vest upon the achievement of specified milestones

Stock-Based Compensation - Summary of Assumptions Used to Determine Grant-Date Fair Value of Options Granted (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected volatility	74.00%	75.00%
Risk-free interest rate, minimum	0.82%	0.31%
Risk-free interest rate, maximum	1.34%	1.67%
Expected term (in years)	6 years	6 years

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Options
Outstanding, beginning of period	6,421,589
Granted	2,240,816
Exercised	(147,499)
Canceled	(547,156)
Outstanding, end of period	7,967,750	6,421,589
Options exercisable— December 31, 2021	1,872,885
Options vested or expected to vest— December 31, 2021	7,967,750
Weighted Average Exercise Price
Outstanding, beginning of period	$ 6.97
Granted	15.84
Exercised	3.96
Canceled	9.44
Outstanding, end of period	9.35	$ 6.97
Options exercisable— December 31, 2021	6.13
Options vested or expected to vest— December 31, 2021	$ 9.35
Weighted Average Remaining Life (in years)
Outstanding	8 years 8 months 12 days	9 years 6 months
Options exercisable— December 31, 2021	8 years 8 months 12 days
Options vested or expected to vest— December 31, 2021	8 years 2 months 12 days
Aggregate Intrinsic Value
Outstanding	$ 36,946	$ 90,112
Options exercisable— December 31, 2021	13,227
Options vested or expected to vest— December 31, 2021	$ 36,946

Stock-Based Compensation - Summary of RSU Activity (Details) - Restricted Stock Units ("RSUs") - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Weighted Average Grant Date Fair Value
Granted		$ 23.60
2020 Plan
Number of Shares Underlying RSUs
Issued and unvested as of January 1, 2021	403,355
Granted	793,629
Vested	(93,500)
Forfeited	(46,500)
Issued and unvested as of December 31, 2021	1,056,984	403,355
Weighted Average Grant Date Fair Value
Issued and unvested as of January 1, 2021	$ 23.60
Granted	14.76
Vested	23.69
Forfeited	23.35
Issued and unvested as of December 31, 2021	$ 16.99	$ 23.60

Stock-Based Compensation - Summary of Restricted Common Stock Award Activity (Details) - Restricted Common Stock	12 Months Ended
	Dec. 31, 2021 shares
Number?of Restricted?Shares
Issued and unvested as of January 1, 2021	370,329
Vested	(251,808)
Forfeited	(80,380)
Issued and unvested as of December 31, 2021	38,141

Stock-Based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 17,542	$ 6,591
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	7,328	2,699
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 10,214	$ 3,892

Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective income tax rate reconciliation
Federal income tax expense at statutory rate	21.00%	21.00%
State taxes—net of federal benefit	5.00%	5.00%
Change in fair value of preferred stock tranche obligations	0.00%	0.00%
Permanent differences and other	(1.00%)	(0.00%)
Federal & state R&D credits	2.00%	1.00%
Increase in valuation allowance	(27.00%)	(27.00%)
Effective income tax rate	0.00%	0.00%

Income Taxes - Significant Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Stock-based compensation	$ 2,333	$ 1,349
Net operating loss carryforwards	51,500	18,858
Credit carryforwards	4,799	1,155
Fixed assets	705	0
Accrued expenses	5,205	580
Lease liability	8,916	0
Total deferred tax assets	73,458	21,942
Valuation allowance	(63,546)	(21,899)	$ (5,607)
Total net deferred tax assets	9,912	43
Deferred tax liabilities:
Fixed assets	0	(43)
Right of use asset	(9,912)	0
Total deferred tax liability	(9,912)	(43)
Total deferred tax assets (liabilities)	$ 0	$ 0

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Increase in valuation allowance for deferred tax assets	$ 41,647	$ 16,292
Unrecognized tax positions, accrued interest or penalties	$ 0	$ 0
Tax returns open year	2018
U.S. Federal
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 188,700
U.S. Federal \| Research and Developments Tax Credit Carryforwards
Income Tax Disclosure [Line Items]
Research and development tax credit carryforwards	$ 3,600
Research and development tax credit carryforwards expiration year	2039
State and Local Jurisdiction
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 188,000
Net operating loss carryforwards expiration year	2038
State and Local Jurisdiction \| Research and Developments Tax Credit Carryforwards
Income Tax Disclosure [Line Items]
Research and development tax credit carryforwards	$ 1,600
Research and development tax credit carryforwards expiration year	2033

Income Taxes - Schedule of Changes in Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Valuation allowance at the beginning of year	$ 21,899	$ 5,607
Decreases recorded as benefit to income tax provision	0	0
Increases recorded to income tax provision	41,647	16,292
Valuation allowance at the end of year	$ 63,546	$ 21,899

Net Loss Per Share - Calculation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net loss	$ (149,291)	$ (59,437)
Denominator:
Weighted-average common shares outstanding—basic and diluted	50,895,044	14,395,955
Net loss per share—basic and diluted	$ (2.93)	$ (4.13)

- Definition

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

+ References

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+ Details

Net Loss Per Share - Potential Dilutive Securities Excluded From Calculation Of Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	9,062,875	7,195,273
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	7,967,750	6,421,589
Unvested Restricted Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	38,141	370,329
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total	1,056,984	403,355

Leases - Additional Information (Details) $ in Millions	1 Months Ended	12 Months Ended
Leases - Additional Information (Details) $ in Millions	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) ft²
Leases [Abstract]
Lease executed date		Jul. 01, 2019
Lease expiration date		Dec. 31, 2021
Additional leased office space \| ft²	68,187		68,187
Lease term	8 years 6 months		8 years 6 months
Lease, description		The Company’s obligation for the payment of base rent for the Premises begins in April 2022, and will be $0.4 million per month, increasing up to $0.5 million during the term of the Lease. The Company has two options to extend the term of the Lease, each for a period of an additional five years.
Monthly rent expense	$ 0.4
Increase in monthly rent expense	$ 0.5
Existence of option to extend lease	true
Option to extend lease		The Company has two options to extend the term of the Lease, each for a period of an additional five years
Additional period of lease	5 years
Non-cash lease expense		$ 2.1	$ 0.8

Leases - Components of Lease Cost for the Sublease (Details) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Leases [Abstract]
Operating Lease Cost	$ 2,126
Short-term Lease, Cost	0
Variable Lease, Cost	573
Total lease cost	$ 2,699

Leases - Supplemental Disclosure of Cash Flow Information Related to Leases for the Sublease (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Leases [Abstract]
Operating cash payments for operating leases	$ 800

Leases - Schedule of Weighted Average Remaining Lease Term and Discount Rate for the Sublease (Details)	Dec. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term - operating leases	8 years 3 months
Weighted-average discount rate - operating leases	5.80%

Leases - Schedule of Future Minimum Lease Payments under Non-Cancelable Operating Leases for the Sublease (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Operating Lease Liabilities Payments Due [Abstract]
2022	$ 4,008
2023	4,706
2024	4,847
2025	4,993
2026	5,143
Thereafter	17,787
Total future minimum lease payments	41,484
Less: imputed interest	(8,848)
Total lease liability	32,636	$ 800
Lease liability	3,893		$ 0
Lease liability, net of current portion	$ 28,743		0
2021			800
2022			3,452
2023			4,706
2024			4,847
2025			4,993
Thereafter			22,930
Total			$ 41,728