0000950170-22-004105 | 10-K | XBRL Viewer

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Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 18,614	$ 17,589
Marketable securities	225,357	131,899
Prepaid and other current assets	2,543	1,263
Total current assets	246,514	150,751
Property and equipment, net	4,804	2,013
Other assets	104	14
Total assets	251,422	152,778
Current liabilities:
Accounts payable	2,556	767
Accrued expenses	5,431	2,637
Total current liabilities	7,987	3,404
Share repurchase liability	593	996
Contingent stock liability		373
Other liabilities	33
Total liabilities	8,613	4,774
Commitments and contingencies (Note 8)
Convertible preferred stock
Total convertible preferred stock		186,151
Stockholders’ equity (deficit)
Common stock, $0.0001 par value, 36,366,101 shares authorized and 7,087,130 issued and outstanding as of December 31, 2021 and 28,037,383 shares authorized and 6,390,137 issued and outstanding as of December 31, 2020; 36,366,101 shares authorized and 31,479,628 issued and outstanding pro forma as of December 31, 2021	4	1
Additional paid-in-capital	333,730	4,879
Accumulated deficit	(90,847)	(43,014)
Accumulated other comprehensive loss	(78)	(13)
Total stockholders’ equity (deficit)	242,809	(38,147)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 251,422	152,778
Series A Convertible Preferred Stock
Convertible preferred stock
Total convertible preferred stock		37,383
Series A-1 Convertible Preferred Stock
Convertible preferred stock
Total convertible preferred stock		34,272
Series B Convertible Preferred Stock
Convertible preferred stock
Total convertible preferred stock		$ 114,496

Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	140,000,000	36,366,101
Common stock, shares issued	16,297	7,087,130
Common stock, shares outstanding	39,763,049	7,087,130
Series A Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	40,000,000
Preferred stock, shares issued	0	40,000,000
Preferred stock, shares outstanding	0	40,000,000
Preferred stock. liquidation preference		$ 40,000
Series A-1 Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	28,000,000
Preferred stock, shares issued	0	28,000,000
Preferred stock, shares outstanding	0	28,000,000
Preferred stock. liquidation preference		$ 35,000
Series B Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	62,499,993
Preferred stock, shares issued	0	62,499,993
Preferred stock, shares outstanding	0	62,499,993
Preferred stock. liquidation preference		$ 114,994
Non-voting Shares
Common stock, shares authorized	10,000,000
Common stock, shares issued	1,150,000
Common stock, shares outstanding	1,150,000

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses
Research and development	$ 34,245	$ 15,278
General and administrative	13,262	7,406
Total operating expenses	47,507	22,684
Loss from operations	(47,507)	(22,684)
Interest and other income (expense), net	(326)	(23)
Net loss	(47,833)	(22,707)
Unrealized loss on marketable securities	(65)	(13)
Total other comprehensive loss	(65)	(13)
Total comprehensive loss	(47,898)	(22,720)
Net loss attributable to common stockholders	$ (47,833)	$ (22,707)
Net loss per common share, basic and diluted	$ (1.64)	$ (3.40)
Weighted average number of common shares outstanding used in computation of net loss per common share, basic and diluted	29,126,373	6,685,066

Statements of Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series A-1 Convertible Preferred Stock	Series B Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2019	$ (17,102)				$ 1	$ 3,204	$ (20,307)
Beginning balance, shares at Dec. 31, 2019		40,000,000	16,000,000
Beginning balance at Dec. 31, 2019		$ 37,383	$ 19,307
Beginning balance, shares at Dec. 31, 2019					6,390,137
Issuance of convertible preferred stock, net of issuance costs			$ 14,966	$ 114,496
Issuance of convertible preferred stock, net of issuance costs, shares			12,000,000	62,499,993
Issuance of common stock upon exercise of stock options	$ 653				$ 0	653
Issuance of common stock upon exercise of stock options, shares	1,629,276				696,993
Stock-based compensation expense	$ 1,022					1,022
Net loss	(22,707)						(22,707)
Unrealized loss on marketable securities	(13)							$ (13)
Ending balance at Dec. 31, 2020	(38,147)				$ 1	4,879	(43,014)	(13)
Ending balance, shares at Dec. 31, 2020		40,000,000	28,000,000	62,499,993
Ending balance at Dec. 31, 2020	$ 186,151	$ 37,383	$ 34,272	$ 114,496
Ending balance, shares at Dec. 31, 2020	7,087,130				7,087,130
Issuance of common stock, net of underwriting discounts and issuance costs	$ 137,166				$ 1	137,165
Issuance of common stock, net of underwriting discounts and issuance costs, shares					8,825,000
Conversion of convertible preferred stock to common stock, value		$ (37,383)	$ (34,272)	$ (114,496)
Conversion of convertible preferred stock to common stock, shares		(40,000,000)	(28,000,000)	(62,499,993)
Conversion of convertible preferred stock to common stock, value	186,151				$ 2	186,149
Conversion of convertible preferred stock to common stock, shares					24,392,498
Issuance of contingent common stock, value	831					831
Issuance of contingent common stock, shares					48,889
Issuance of common stock upon exercise of stock options	$ 721					721
Issuance of common stock upon exercise of stock options, shares	149,707				543,649
Issuance of common stock under 2021 employee stock purchase plan	$ 207					207
Issuance of common stock under 2021 employee stock purchase plan, shares					15,883
Stock-based compensation expense	3,778					3,778
Net loss	(47,833)						(47,833)
Unrealized loss on marketable securities	(65)							(65)
Ending balance at Dec. 31, 2021	$ 242,809				$ 4	$ 333,730	$ (90,847)	$ (78)
Ending balance, shares at Dec. 31, 2021		0	0	0
Ending balance, shares at Dec. 31, 2021	39,763,049				40,913,049

Statements of Convertible Preferred Stock and Stockholders' Deficit (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Statement Of Stockholders Equity [Abstract]
Net of underwriting discounts and issuance costs	$ 12,858,764

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (47,833)	$ (22,707)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	623	447
Accretion and amortization of marketable securities, net	427	95
Stock-based compensation expense	3,778	1,022
Fair value adjustment of contingent stock liability	735	310
Gain on disposal of property and equipment	(33)
Other		7
Changes in operating assets and liabilities:
Prepaid and other current assets	(1,280)	553
Other assets	(90)	6
Accounts payable	1,323	100
Accrued expenses	2,329	955
Other liabilities	33
Net cash used in operating activities	(39,988)	(19,212)
Cash flows from investing activities:
Purchases of property and equipment	(2,437)	(1,286)
Purchases of marketable securities	(275,879)	(158,237)
Maturities of marketable securities	181,929	26,224
Net cash used in investing activities	(96,387)	(133,300)
Cash flows from financing activities:
Issuance costs	(12,858,764)
Proceeds from issuance of common stock	139,523
Payment of partial settlement of contingent stock liability	(277)
Proceeds from exercise of stock options	317	1,649
Net cash provided by financing activities	137,400	131,123
Net increase (decrease) in cash and cash equivalents	1,025	(21,389)
Cash and cash equivalents at beginning of period	17,589	38,978
Cash and cash equivalents at end of period	18,614	17,589
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions included in accounts payable and accrued expenses	1,028	86
Preferred stock issuance costs included in accounts payable and accrued expenses		11
2021 Employee Stock Purchase Plan
Cash flows from financing activities:
Proceeds from issuance of common stock	206
Series A-1 Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from issuances of convertible preferred stock		15,000
Series B Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from issuances of convertible preferred stock		115,000
Common Stock
Cash flows from financing activities:
Issuance costs	$ (2,369)
Preferred Stock
Cash flows from financing activities:
Issuance costs		$ (526)

Nature of Business and Liquidity

12 Months Ended

Dec. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Business and Liquidity

1. Nature of Business and Liquidity

Talaris Therapeutics, Inc. (“Talaris” or the “Company”) is a late-clinical stage, cell therapy company developing an innovative method of allogeneic hematopoietic stem cell transplantation ("allo-HSCT"), called "Facilitated Allo-HSCT Therapy", that the Company believes has the potential to transform the standard of care in solid organ transplantation, certain severe autoimmune diseases and certain severe blood, immune and metabolic disorders. The Company believes that these indications, individually and collectively, represent a significant unmet need and commercial opportunity. The Company maintains corporate offices in Boston, Massachusetts, a laboratory in Houston, Texas and its cell processing facility in Louisville, Kentucky.

Initial Public Offering

The Company completed an initial public offering (“IPO”) on May 11, 2021 in which the Company issued and sold 8,825,000 shares of its common stock at a public offering price of $17.00 per share. The Company’s aggregate gross proceeds from the sale of shares in the IPO was $150.0 million before underwriting discounts and commissions and other expenses of approximately $12.9 million. Upon completion of the offering, the Company’s outstanding convertible preferred stock was automatically converted into shares of common stock and non-voting common stock. Following the IPO, there were no shares of preferred stock outstanding. Prior to the IPO, on April 30, 2021, the Company’s board of directors and shareholders approved a one-for-5.35 reverse share split of issued and outstanding common shares and incentive shares and a proportional adjustment to the existing conversion ratios for the Company’s convertible preferred stock.

Liquidity

The accompanying financial statements have been prepared assuming that the Company will continue as a going concern. Management has evaluated whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the financial statements are issued. Since its inception, the Company has incurred net losses and negative cash flows from operations. During the years ended December 31, 2021 and 2020, the Company incurred a net loss of $47.8 million and $22.7 million, respectively, and used $40.0 million and $19.2 million in cash for operations, respectively. In addition, as of December 31, 2021, the Company had an accumulated deficit of $90.8 million. The Company expects to continue to generate operating losses and negative cash flows for the foreseeable future. The Company currently expects the cash and cash equivalents of $18.6 million and marketable securities of $225.4 million as of December 31, 2021, will be sufficient to fund its operating expenses and capital requirements for more than 12 months from the date the financial statements are available to be issued.

Additional funding will be needed to finance future clinical, pre-clinical, manufacturing and commercial activities. There is no assurance the Company will be successful in obtaining such additional financing on terms acceptable to it, if at all, and it may not be able to enter into other arrangements. If the Company is unable to obtain funding, it could be forced to delay, reduce or eliminate our research and development programs, portfolio expansion or commercialization efforts, which could adversely affect its business prospects and ability to continue operations.

The Company is subject to risks common to companies in the biopharmaceutical industry. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for its intellectual property will be maintained, that any products developed will obtain required regulatory approval, or that any approved products will be commercially viable. Even if the development efforts are successful, it is uncertain when, if ever, the Company will generate significant product sales and ultimately net income.

Coronavirus Pandemic

In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. The worldwide COVID-19 pandemic has affected and may affect in the future the Company’s ability to initiate and complete preclinical studies, delay the initiation and completion of its current and planned clinical trials, disrupt regulatory activities or have other adverse effects on its business, results of operations, financial condition and prospects. In addition, the pandemic has caused substantial disruption in the financial markets and may adversely impact economies worldwide, both of which could adversely affect the Company’s business, operations and ability to raise funds to support its operations.

The Company cannot be certain what the overall impact of the COVID-19 pandemic will be on its business, and it has the potential to adversely affect its business, financial condition, results of operations and prospects.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Summary Of Significant Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (US GAAP).

Use of Estimates

The preparation of financial statements in conformity with US GAAP requires management to make judgments, assumptions, and estimates that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of financial statements, and the reported amounts of income and expense during the reporting period. The most significant estimates relate to the determination of fair value of the Company’s common stock, determination of the fair value of stock option grants and estimates related to the amount of accrued research and development expenses as of the balance sheet date. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, and makes adjustments when the facts and circumstances dictate. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2021 and 2020, cash consists primarily of checking and savings deposits and money market fund holdings.

Marketable Securities

The Company classifies its marketable securities as available-for-sale securities, which are carried at their fair value based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive loss, a separate component of stockholders’ deficit. Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Equipment and furniture and fixtures are depreciated over five or seven year lives. Leasehold improvements are amortized over the shorter of the lease term or the five-year estimated useful life of the asset. Computer equipment and computer software are depreciated over three years. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance are expensed as incurred.

Impairment of Long-Lived Assets

The Company evaluates its long-lived assets, which consist primarily of property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. No impairments have been identified as of December 31, 2021 and 2020.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. The Company’s investment policy includes guidelines regarding the quality of the financial institutions and financial instruments and defines allowable investments that it believes minimizes the exposure to

concentration of credit risk. The Company may invest in money market funds (minimum of $1 billion in assets), U.S. Treasury securities, corporate debt, bank debt, U.S. government-related agency securities, other sovereign debt, municipal debt and commercial paper. These deposits may exceed federally insured limits. The Company has not experienced any losses historically in these accounts and believes that it is not exposed to significant credit risk as our deposits are held at financial institutions that management believes to be of high credit quality.

Fair Value of Financial Instruments

Fair value is defined as the price that the Company would receive to sell an investment in a timely transaction or pay to transfer a liability in a timely transaction with an independent buyer in the principal market, or in the absence of a principal market, the most advantageous market for the investment or liability. A framework is used for measuring fair value utilizing a three-tier hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 investments) and the lowest priority to unobservable inputs (Level 3 investments).

The three levels of the fair value hierarchy are as follows:

•

Level 1 inputs: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

•

Level 2 inputs: Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and,

•

Level 3 inputs: Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.

Financial instruments are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment and considers factors specific to the investment.

The Company’s money market funds and marketable securities are carried at fair value determined according to the fair value hierarchy described above (Level 1 and Level 2, respectively).

The Company’s contingent stock liability as of December 31, 2020 (see Note 3) is carried at fair value determined according to the fair value hierarchy described above (Level 3).

Research and Development Expenses

Research and development expenses include (i) employee-related expenses, including salaries, benefits, travel and stock-based compensation expense; (ii) external research and development expenses incurred under arrangements with third parties, such as contract research organization agreements, investigational sites, and consultants; (iii) the cost of acquiring, developing, and manufacturing clinical study materials; (iv) costs associated with preclinical and clinical activities and regulatory operations; (v) costs incurred in development of intellectual property; and (vi) an allocated portion of facilities and other infrastructure costs associated with our research and development activities. Costs incurred in connection with research and development activities are expensed as incurred.

The Company enters into consulting, research, and other agreements with commercial entities, researchers, universities, and others for the provision of goods and services. Such arrangements are generally cancelable upon reasonable notice and payment of costs incurred. Costs are considered incurred based on an evaluation of the progress to completion of specific tasks under each contract using information and data provided by the respective vendors, including the Company’s clinical sites. These costs consist of direct and indirect costs associated with specific projects, as well as fees paid to various entities that perform certain research on behalf of the Company. Depending upon the timing of payments to the service providers, the Company recognizes prepaid expenses or accrued expenses related to these costs. These accrued or prepaid expenses are based on management’s estimates of the work performed under service agreements, milestones achieved, and experience with similar contracts. The Company monitors each of these factors and adjusts estimates accordingly.

Stock-Based Compensation

The Company measures all stock options and other stock-based awards granted to employees, nonemployees, and directors based on the fair value on the date of the grant and recognizes stock-based compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues stock option awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company’s policy is to account for forfeitures when they occur.

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

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company recently completed its IPO 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 it has adequate historical data regarding the volatility of its own traded stock price. 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 expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the US 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 zero because the Company has never paid cash dividends on common stock and does not expect to pay any cash dividends in the foreseeable future.

Prior to the Company’s IPO, the Company considered the estimated fair value of the common stock as of the measurement date in determining the exercise price for options granted. The estimated fair value of the common stock was determined at each grant date based upon a variety of factors, including the illiquid nature of the common stock, arm’s-length sales of the Company’s capital stock (including convertible preferred stock), the effect of the rights and preferences of the preferred shareholders, and the prospects of a liquidity event. Among other factors are the Company’s financial position and historical financial performance, forecasted future operations of the Company, an evaluation or benchmark of the Company’s competition, and the current business climate in the marketplace. Significant changes to the key assumptions underlying the factors used could result in different fair values of common stock at each valuation date. The fair value for options granted since the Company’s IPO are based on the closing stock price on grant date.

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 tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. 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.

The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions. These reserves are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of income tax expense. The Company had no significant uncertain tax positions as of December 31, 2021 and December 31, 2020.

Basic and Diluted Net Loss Per Share

The Company calculates basic and diluted net loss per share using the two-class method. The two-class method requires income available to common stockholders for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. The Company’s Series A convertible preferred stock, Series A-1 convertible preferred stock and Series B convertible preferred stock are participating securities. These participating securities do not contractually require the holders of such shares to participate in the Company’s losses. As such, net losses for the years presented were not allocated to the Company’s participating securities. Accordingly, basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares outstanding during the period plus the dilutive effects of potentially dilutive securities outstanding during the period. Potentially dilutive securities include vested and unexercised stock options, restricted stock issued upon early exercise of stock options, convertible preferred shares and contingent stock liabilities. The dilutive effect of stock options and contingent stock liabilities are computed using the treasury stock method and the dilutive effect of convertible preferred shares is calculated using the if-converted method. The Company has generated a net loss for all periods presented, therefore diluted net loss per share is the same as basic net loss per share since the inclusion of potentially dilutive securities would be anti-dilutive.

Segments

Operating segments are defined as components of an entity for which separate financial information is made available and is regularly evaluated by the chief operating decision maker (“CODM”) in making decisions regarding resource allocation and assessing performance. The Company’s CODM is the chief executive officer and operations are managed as a single segment for the purposes of assessing performance and making operating decisions.

Comprehensive Loss

Comprehensive loss represents net loss for the period plus the results of certain other changes in stockholders’ equity (deficit). The Company’s comprehensive loss included unrealized gains related to marketable securities for the years ended December 31, 2021 and 2020.

Recently Issued Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments—Credit Losses, (“ASC 326”), which introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The new model will apply to (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost; (2) loan commitments and certain other off-balance-sheet credit exposures; (3) debt securities and other financial assets measured at fair value through other comprehensive income; and (4) beneficial interests in securitized financial assets. The adoption of ASC 326 in January 2021 had no material impact on the Company’s financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which eliminates the current tests for lease classification under U.S. GAAP and requires lessees to recognize the right-to-use assets and related lease liabilities in the balance sheet. The new standard provides for a modified retrospective application. ASU 2016-02 is effective for interim and annual period beginning after December 15, 2021.

The Company plans to adopt ASU 2016-02 on January 1, 2022. The Company expects to elect the package of practical expedients permitted under the transition guidance within the new standard, which, among other things, allows the Company to carry forward historical lease classification. The Company is completing its evaluation of the impact of adoption of ASU 2016-02 on its financial statements and expects to recognize a lease liability and related right-of-use assets on its balance sheet of approximately $3.4 million. The Company does not expect the standard to have a material impact on its results of operations or cash flows. In addition, the Company is currently implementing changes to processes and controls to support lease accounting and related disclosures under the new standard.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (ASC 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. ASU No. 2018-13 removes certain disclosures, modifies certain disclosures, and adds additional disclosures. ASU No. 2018-13 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. The adoption of ASU 2018-13 in January 2020 had no material impact on the Company’s financial statements.

Fair Value of Financial Assets and Liabilities

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value of Financial Assets and Liabilities

3. Fair Value of Financial Assets and Liabilities

The following table presents information about the Company’s financial instruments that are measured at fair value on a recurring basis and indicates the fair value hierarchy of the inputs the Company utilized to determine such fair value (in thousands):


	December 31, 2021
	Total		Level 1		Level 2		Level 3
Financial assets:
Money market funds (cash equivalents)	$	10,319	$	10,319	$	—	$	—
Marketable securities		225,357		27,186		198,171		—
Total financial assets measured at fair value	$	235,676	$	37,505	$	198,171	$	—


	December 31, 2020
	Total		Level 1		Level 2		Level 3
Financial assets:
Money market funds (cash equivalents)	$	13,943	$	13,943	$	—	$	—
Marketable securities		131,899		11,169		120,730		—
Total financial assets measured at fair value	$	145,842	$	25,112	$	120,730	$	—
Financial liabilities:
Contingent stock liability	$	373	$	—	$	—	$	373
Total financial liabilities measured at fair value	$	373	$	—	$	—	$	373

The contingent stock liability in the table above represents the fair value of contingent equity consideration equal to 65,186 shares of common stock contingently issuable to the University of Louisville Research Foundation Inc. (ULRF) in connection with its amended and restated exclusive license agreement with the Company (see Note 8). In conjunction with the Company's IPO, the Company issued 48,889 shares of common stock and paid the cash equivalent fair value of 16,297 shares, or $0.3 million, to ULRF in May 2021 (see note 8). A rollforward of the contingent common stock liability, which is measured at fair value for the years ended December 31, 2021 and 2020, is represented as follows (in thousands):


Fair value as of January 1, 2020	$	63
Change in fair value		310
Fair value as of December 31, 2020		373
Change in fair value		735
Share issuance in partial settlement of contingent stock		(831	)
Cash payment in partial settlement of contingent stock		(277	)
Fair value as of December 31, 2021	$	—

Valuation techniques used to measure fair value maximize the use of relevant observable inputs and minimize the use of unobservable inputs. Prior to the Company’s IPO, the Company’s contingent stock liability was classified within Level 3 of the fair value hierarchy because its fair value measurement is based, in part, on significant inputs not observed in the market, which incorporates assumptions and estimates to value the Company’s common stock. As there was no public market for the Company’s common stock prior to May 2021, the estimated fair value was determined by the Company’s board of directors with input from management, considering the most recently available third-party valuations of common stock, and the board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of each valuation. Historically, these third-party valuations of the Company’s common stock were performed contemporaneously when events occurred which management believed would have an impact on the valuation of the Company. The Company’s common stock valuation was prepared using the option-pricing method, (“OPM”), which uses a market approach to estimate enterprise value. The fair value of the Company’s common stock used to value the contingent stock liability as of December 31, 2020 was $5.72. The Company's IPO price of $17.00 was used to determine the contingent stock value prior to settlement in cash and share issuance.

- 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

Marketable Securities

12 Months Ended

Dec. 31, 2021

Marketable Securities [Abstract]

Marketable Securities

4. Marketable Securities

The fair value of the Company’s marketable securities as of December 31, 2021 and December 31, 2020 is based on level 1 and level 2 inputs. The Company’s investments consist mainly of U.S. government and agency securities, government-sponsored bond obligations and certain other corporate debt securities. Fair value is determined by taking into consideration valuations obtained from third-party pricing services. The third-party pricing services utilize industry standard valuation

models, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities; issuer credit spreads; benchmark securities; and other observable inputs. There were no transfers between levels within the hierarchy during the years ended December 31, 2021 and December 31, 2020. The Company has assessed U.S. government treasuries as level 1 and all other marketable securities as level 2 within the fair value hierarchy of ASC 820. The Company classifies its entire investment portfolio as available-for-sale as defined in ASC 320, Debt Securities. Securities are carried at fair value with the unrealized gains (losses) reported in other comprehensive loss.

As of December 31, 2021 and December 31, 2020, none of the Company’s investments were determined to be other than temporarily impaired.

The following table summarizes the Company’s investments (in thousands):


	December 31, 2021
	Amortized Cost		Unrealized Gain		Unrealized (Loss)			Estimated Fair Value
Commercial paper	$	179,151	$	38	$	(47	)	$	179,142
Corporate debt securities		31,244		—		(58	)		31,186
Government and agency securities		15,040		—		(11	)		15,029
Total	$	225,435	$	38	$	(116	)	$	225,357

Prepaid and Other Current Assets

12 Months Ended

Dec. 31, 2021

Prepaid Expense And Other Assets Current [Abstract]

Prepaid and Other Current Assets

5. Prepaid and Other Current Assets

Prepaid and other current assets consisted of the following (in thousands):


	December 31,
	2021		2020
Prepaid insurance	$	1,121	$	102
Prepaid research and development expenses		782		702
Other current assets		640		459
Total prepaid and other current assets	$	2,543	$	1,263

Property and Equipment, Net

12 Months Ended

Dec. 31, 2021

Property Plant And Equipment [Abstract]

Property and Equipment, Net

6. Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	December 31,
	2021			2020
Equipment	$	4,449		$	2,666
Leasehold improvements		821			580
Computer equipment		953			264
Furniture and fixtures		426			255
Construction in progress		952			491
Total property and equipment		7,601			4,256
Less accumulated depreciation		(2,797	)		(2,243	)
Property and equipment, net	$	4,804		$	2,013

Depreciation expense was $0.6 million and $0.4 million for the years ended December 31, 2021 and 2020, respectively.

Accrued Expenses

12 Months Ended

Dec. 31, 2021

Accrued Liabilities Current [Abstract]

Accrued Expenses

7. Accrued Expenses

Accrued expenses consisted of the following (in thousands):


	December 31,
	2021		2020
Compensation and benefit costs	$	3,320	$	1,400
Research and development expenses		854		788
Professional fees, consulting and other		1,257		449
Total accrued expenses	$	5,431	$	2,637

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

8. Commitments and Contingencies

Leases

The Company currently has six active lease agreements for office and laboratory space and related equipment. The primary lease is located on the University of Louisville campus in Louisville, Kentucky (the “Louisville Lease”). This lease has a termination date in November 2023, with an option to extend for three additional years at the Company’s discretion. In May 2020, the Company added additional office and laboratory space to the Louisville Lease. In September 2021, the Company entered into a sublease agreement for additional office space in Louisville, Kentucky. This sublease has a termination date in November 2023. The Company maintained a third lease for ancillary office space in Louisville, Kentucky. This lease was terminated in December 2021.

The Company maintains a lease for office space in Wellesley, Massachusetts, that had an original termination date in March 2021. The Company entered into a month-to-month lease agreement for the office space in Wellesley effective as of April 2021 and in June 2021, finalized an amended lease agreement. The amended lease commencement date will be the later of September 2021 or the date the landlord substantially completes agreed-upon renovations. The term of the lease will be 39 months from the commencement date. The Company will maintain its current office space in Wellesley until the commencement of the amended lease agreement. The amended lease had not commenced as of December 31, 2021.

In July 2021, the Company entered into a lease agreement for laboratory space in Houston, Texas. The agreement has a term of five months with the option to extend on a month-to-month basis at the end of the original term. The Company utilized the space under this lease on a temporary basis while construction of a permanent lease was completed. This lease was terminated in December 2021. In July 2021, the Company entered into a second lease agreement for laboratory space in Houston, Texas (the “Houston Lease”). The Houston Lease commencement date will be the later of September 2021 or the date the landlord substantially completes agreed-upon renovations. The term of the lease will be 36 months from the commencement date. The Houston lease commenced in January 2022.

The future minimum rent payments relating to all four of the Company’s ongoing facility operating leases under the terms and conditions existing as of December 31, 2021, as well as amendments the Company has entered into between the date of these financial statements and the date they were available to be issued (as described in Note 16), are summarized as follows (in thousands):


Years Ending December 31,
2022	$	907
2023	$	1,065
2024	$	937
2025	$	700
2026 and beyond	$	437
Total	$	4,046

The Company incurred rent expense of $0.7 million and $0.6 million for the years ended December 31, 2021 and 2020, respectively.

License Agreement

In October 2018, the Company entered an amended and restated exclusive license agreement with the ULRF related to certain licensed patent rights and know-how related to human facilitating cells for its Facilitated Allo-HSCT Therapy approach.

Pursuant to the ULRF License Agreement, ULRF granted the Company an exclusive, worldwide license under such patents and a nonexclusive royalty-bearing, worldwide license for such know-how to research, develop, commercialize and manufacture FCR001 and products containing FCR001 in all fields, without limitation. ULRF also granted the Company the right to grant sublicenses in accordance with the ULRF License Agreement. Under the terms of the agreement, the Company is obligated to compensate ULRF three percent of net sales of all licensed products sold, one third of any non-royalty sublicensing income, and up to $1.625 million in regulatory and sales milestones on each licensed product upon the occurrence of specific events as outlined in the license agreement; and annual license maintenance fees.

In addition, upon execution of the ULRF License Agreement, the Company granted contingent equity consideration equal to 65,186 shares of common stock to ULRF. On or prior to the Company’s first underwritten public offering or any transaction that is treated as a deemed liquidation event, the Company may either issue to ULRF the 65,186 shares in common stock or make a cash payment equal to the 65,186 shares of common stock multiplied by either the price per share of common stock in the underwritten public offering or by the price per share of common stock received in connection with such deemed liquidation event.

Coincident with the completion of the Company’s IPO, the Company issued 48,889 shares of common stock to ULRF and provided a cash payment of approximately $0.3 million in lieu of issuing the remaining 16,297 shares of common stock. As of December 31, 2021, the contingent stock liability was fully satisfied. As of December 31, 2020, the Company measured the fair value of the contingent equity consideration and recorded a contingent stock liability of $0.4 million in other liabilities (see Note 3).

The Company incurred $0.1 million in expense in February 2021 related to an annual maintenance fee pursuant to the license agreement for the year ended December 31, 2021. The Company incurred a $0.1 million milestone payment to ULRF in June 2020 which was recorded as research and development expense. The Company also incurred $0.1 million in expense in February 2020 related to the annual maintenance fee for the year ended December 31, 2020.

Legal Proceedings

The Company is not currently a 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 its legal proceedings.

Convertible Preferred Stock

12 Months Ended

Dec. 31, 2021

Convertible Preferred Stock [Abstract]

Convertible Preferred Stock

9. Convertible Preferred Stock

Issuances of Convertible Preferred Stock

In November 2018, the Company issued 22,500,000 shares of Series A Convertible Preferred Stock at $1.00 per share for gross cash proceeds of $22.5 million. The Company incurred issuance costs of $2.0 million, which have been recorded as a reduction to the value of Series A Convertible Preferred Stock in mezzanine equity in the accompanying balance sheets. In connection with the initial issuance of the Series A Convertible Preferred Stock, the purchasers received the right to purchase, and the Company had the obligation to sell, additional shares of Series A Convertible Preferred Stock at $1.00 per share and a unit, comprised of one share of Series A-1 Convertible Preferred Stock and one product interest right (each a “Unit”), at $1.25 per Unit (together, the “Tranche Rights”) upon achieving certain milestones related to the Company’s research and clinical developments in a series of tranches (the “Tranche 2,” “Tranche 3,” and “Tranche 4”) milestones.

In December 2019, the Tranche 2 milestone was met and the Company issued an additional 17,500,000 shares of Series A Convertible Preferred Stock at $1.00 per share for gross cash proceeds of $17,500,000 and 16,000,000 Units (consisting of 16,000,000 shares of Series A-1 Convertible Preferred Stock and 16,000,000 shares of product interest rights) at $1.25 per Unit for gross cash proceeds of $20.0 million. The Company incurred issuance costs of $1.3 million in relation to Tranche 2, which have been recorded as a reduction to the value of Series A-1 Convertible Preferred Stock in mezzanine equity in the accompanying balance sheets.

In August 2020, the holders of Series A-1 Convertible Preferred Stock voted to amend the Preferred Stock and Unit Purchase Agreement (“SPA”) and waive the requirements of the Tranche 3 milestone. The Company issued an additional 12,000,000 Units (consisting of 12,000,000 shares of Series A-1 Convertible Preferred stock and 12,000,000 shares of product interest rights) at $1.25 per Unit for gross cash proceeds of $15.0 million.

In September 2020, the Company issued 62,499,993 shares of Series B Convertible Preferred Stock at $1.84 per share for gross cash proceeds of $115.0 million. The Company incurred issuance costs of $0.5 million in relation to the issuance of Series B Convertible Preferred Stock, which have been recorded as a reduction to the value of Series B Convertible Preferred Stock in mezzanine equity in the accompanying balance sheets.

In conjunction with the Series B Convertible Preferred Stock financing in September 2020, all holders of the Company’s preferred stock entered into an amendment to the SPA to terminate all rights, liabilities and obligations in respect to the Tranche 4 milestone.

Tranche Rights

The Company determined that the Tranche Rights did not meet the definition of a freestanding financial instrument because the Tranche Rights are not legally detachable from the initial Series A Convertible Preferred Stock issued. The Company made this determination due to the express prohibition of the transfer of the Tranche Rights. Further, the Company determined that the Tranche Rights do not meet the definition of an embedded derivative that would require bifurcation from the initial Series A Preferred Stock issued. Therefore, at the initial issuance of the Series A Convertible Preferred Stock in November 2018, there was no separate recognition of the Tranche Rights.

Product Interest Rights

After the first commercial sale of product, the product interest right entitles the holders to a product interest payment for each product interest right held equal to 1/48,000,000 multiplied by 9% of net product sales on a territory-by-territory basis. If the Company enters into a license of rights to develop and/or commercialize a product, the holder is entitled to a product interest payment for each product interest right equal to 1/48,000,000 multiplied by 30% of licensing income. If the holder does not participate or events occur in which the holder transfers its ownership, it must determine to transfer either its shares or the unit purchase right. If the holder elects to receive a product interest payment, then a corresponding total number of Series A-1 Convertible Preferred Stock initially underlying a Unit (the “Unit Share”), will be canceled and forfeited. The total number of Unit Shares canceled and forfeited will be determined by dividing the product interest payment received by the fair value of the Unit Share at such time. The product interest right payment term shall commence upon the first commercial sale of product, on a territory-by-territory basis, and continue until the fifteenth anniversary thereafter, or any earlier date that there are no remaining product interest rights outstanding.

If at any time, the Unit is transferred, the holder must elect to transfer either (i) the Unit Share underlying the Unit or (ii) the product interest right underlying the Unit. If the holder elects to transfer the Unit Share, the corresponding product interest right underlying the Unit shall be automatically canceled, forfeited, and extinguished for no consideration. If the holder elects to transfer the product interest right, the corresponding Unit Share unit shall be automatically canceled and forfeited for no consideration.

The Company determined the product interest rights did not meet the definition of a freestanding financial instrument because the product interest rights are not legally detachable or separately exercisable from the Unit Shares. Further, the Company determined that the product interest rights do not meet the definition of an embedded derivative that would require bifurcation from the Unit Share. Therefore, upon issuance of Units in December 2019, there was no separate recognition of the product interest rights.

In March 2021, the Company entered into a termination agreement with the holders of Series A and Series A-1 Convertible Preferred Stock to terminate the Product Interest Rights Agreement between the parties effective immediately prior to, but subject to the closing of the Company’s initial public offering. The termination agreement cancelled all product interest rights associated with the Series A-1 Convertible Preferred Stock. There was no value offered in exchange for the cancellation.

Rights and Privileges of Convertible Preferred Stock

The rights and privileges of the Series A, Series A-1 and Series B Convertible Preferred Stock (together, “Convertible Preferred Stock”) are as follows:

Voting Rights—The holders of each series of Convertible Preferred Stock are entitled to vote on all matters and shall have the number of votes equal to the number of shares of common stock into which the preferred stock is convertible.

Dividends—The Company shall not declare, pay, or set aside any dividends on shares of any other class or series of capital stock (other than dividends on shares of common stock payable in shares of common stock), unless the holders of the Convertible Preferred Stock receive a dividend on each outstanding share of Convertible Preferred Stock in an amount at least equal to (i) in the case of a dividend on common stock or any class or series that is convertible into common stock, that dividend per share of Convertible Preferred Stock as would equal the product of (A) the dividend payable on each share of such class or series determined, if applicable, as if all shares of such class or series had been converted into common stock and (B) the number of shares of common stock issuable upon conversion of a share of the applicable series of Convertible Preferred Stock or (ii) in the case of a dividend on any class or series that is not convertible into common stock, at a rate per share of the applicable series of Convertible Preferred Stock determined by (A) dividing the amount of the dividend payable on each share of such class or series of capital stock by the original issuance price of such class or series of capital stock and (B) multiplying such fraction by an amount equal to the original issue price of the applicable series of Convertible Preferred Stock. No dividends were declared or paid during the years ended December 31, 2021 and December 31, 2020.

Liquidation Preference—In the event of any voluntary or involuntary liquidation, dissolution, or winding-up of the Company, the holders of shares of Convertible Preferred Stock will receive, in preference to any distribution to the holders of common stock an amount per share equal to the greater of (i) the applicable original issue price of such series of Convertible Preferred Stock, plus any dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Convertible Preferred Stock been converted into common stock immediately prior to such liquidation, dissolution, winding-up, or deemed liquidation event. If upon any such liquidation, dissolution, or winding-up of the Company or deemed liquidation event, the assets available for distribution to the Company’s stockholders are not sufficient to pay the holders of Convertible Preferred Stock the full amount to which they shall be entitled, the holders of Convertible Preferred Stock shall share ratably in any distribution of the assets available for distribution in proportion to the respective amounts, which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

In the event of a deemed liquidation event, if the Company does not effect a dissolution within 90 days after such deemed liquidation event, each holder of Convertible Preferred Stock has the right to require the redemption of such shares, and if voting together as a majority, has the right to require redemption of all outstanding Convertible Preferred Stock in accordance with the liquidation preferences afforded to holders of the Convertible Preferred Stock. Any shares of Convertible Preferred Stock that are redeemed or otherwise acquired by the Company or any of its subsidiaries be automatically and immediately canceled and retired and shall not be reissued, sold, or transferred. Neither the Company nor any of its subsidiaries may exercise any voting or other rights granted to the holders of Convertible Preferred Stock following redemption. A Deemed Liquidation Event shall include a merger or consolidation (other than one in which the capital stock of the Company outstanding immediately prior to such merger or consolidation continue to represent a majority by voting power of the capital stock of the surviving corporation) or a sale, lease, transfer, exclusive license, or other disposition of all or substantially all of the assets of the Company.

Conversion

Conversion Ratio—Each share of Convertible Preferred Stock shall be convertible, at the option of the holder thereof, at any time into such number of fully paid and nonassessable shares of common stock as is determined by dividing the applicable original issue price by the applicable conversion price (Series A original issue price is $1.00 per share and applicable conversion price is $5.35 per share; Series A-1 original issue price is $1.25 and applicable conversion price is $6.69 per share; Series B original issue price is $1.84 per share and applicable conversion price is $9.84 per share), subject to adjustment in the case of termination or fractional shares.

Mandatory Conversion—All outstanding shares of Convertible Preferred Stock are automatically convertible based upon either (a) the closing of a firm-commitment underwritten public offering in which the aggregate gross proceeds to the Company of at least $60,000,000 of gross proceeds to the Company and have an offering price to the public of at least $9.84 per share or (b) the vote or written consent of holders of at least a majority of the Convertible Preferred Stock outstanding at that time with respect to the conversion of the Convertible Preferred Stock then all outstanding shares of Convertible Preferred Stock shall automatically be converted into shares of common stock at the then effective conversion rate and such shares may not be reissued. Upon the completion of the Company’s IPO in May 2021, all Convertible Preferred Stock was converted to shares of common stock or non-voting common stock. Series A Convertible Preferred Stock was converted into 7,476,632 shares of common stock, Series A-1 Convertible Preferred Stock was converted into 5,233,637 shares of common stock and Series B Convertible Preferred Stock was converted into 10,532,229 shares of common stock and 1,150,000 shares of non-voting common stock.

Common Stock

12 Months Ended

Dec. 31, 2021

Stockholders Equity Note [Abstract]

Common Stock

10. Common Stock

Common Stock

On April 30, 2021, the Company’s stockholders approved the third amended and restated certificate of incorporation of the Company, which included the authorization of 10,000,000 shares of undesignated preferred stock with a par value of $0.0001, authorization of 140,000,000 shares of voting common stock and 10,000,000 shares of non-voting common stock. As of December 31, 2021, no undesignated preferred stock was outstanding.

Common Stock Reserved

The number of shares of common stock that have been reserved for the potential conversion of Preferred Stock, outstanding stock options granted and stock options available for grant under the Company’s 2021 Stock Option and Incentive Plan (the “2021 Plan”) and the 2018 Equity Incentive Plan (the “2018 Plan”) and shares reserved for issuance under the Company’s 2021 Employee Stock Purchase Plan (the “2021 ESPP”) are as follows:


	December 31,
	2021		2020
Conversion of Series A Preferred Stock		—		7,476,632
Conversion of Series A-1 Preferred Stock		—		5,233,637
Conversion of Series B Preferred Stock		—		11,682,229
Restricted stock related to early exercise of common stock options		538,340		932,279
Outstanding common stock options		3,643,796		2,745,185
Shares reserved for issuance under equity incentive plans		2,702,995		1,143,820
Shares reserved for issuance under the 2021 Employee Stock Purchase Plan		837,088		—
Contingent stock		—		65,186
Total		7,722,219		29,278,968

- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Stock-Based Compensation

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11. Stock-Based Compensation

2021 Employee Stock Purchase Plan

In April 2021, the Company’s board of directors and stockholders approved the 2021 ESPP. The 2021 ESPP became effective immediately prior to the effectiveness of the Company’s registration statement on Form S-1 for its IPO. The 2021 ESPP provides employees the opportunity to purchase shares at a 15% discount at the lower of the share price at the beginning or end of six-month offering periods. 852,971 shares have been reserved and approved for this purpose for the 2021 plan year. The number of shares reserved and available for issuance under the plan will increase on January 1, 2022, and each January 1 thereafter through January 1, 2031, by the lesser of (A) 3,000,000 shares of common stock, (B) 1% of the cumulative number of shares of common stock issued and outstanding on the immediately preceding December 31st or (C) such lesser number of shares of common stock as determined by the Board. The expense incurred under this plan for the year ended December 31, 2021 was not material to the financial statements. The amounts have been included in the total stock-based compensation line items in the accompanying financial statements and disclosures.

Equity Incentive Plans

The April 2021, the Company’s board of directors and stockholders approved the 2021 Plan and terminated the 2018 Plan with respect to any unissued awards. The 2021 Plan became effective immediately prior to the effectiveness of the Company’s registration statement on Form S-1 for its IPO. The 2021 Plan provides for the issuance of up to 3,015,907 new share-based awards, as well as the 3,381,382 options to purchase common stock then outstanding under the 2018 Plan, for a total of 6,397,289 shares. To the extent outstanding options granted under the 2018 Plan are cancelled, forfeited, or otherwise terminated without being exercised and would otherwise have been returned to the share reserve under the 2018 Plan, the number of shares underlying such awards will be available for future grant under the 2021 Plan.

As of December 31, 2021, 2,702,995 shares remained available for future grant under the 2021 Plan. 3,569,030 options were outstanding under the 2021 Plan and 2018 Plan as of December 31, 2021.

The Company’s 2021 Plan provides for the Company to sell or issue common stock or restricted common stock or to grant incentive stock options or nonqualified stock options for the purchase of common stock, to employees, nonemployees and members of the board of directors of the Company. The 2021 Plan is administered by the board of directors or at the discretion of the board of directors by the compensation committee of the board. The exercise prices, vesting periods, and other

restrictions are determined at the discretion of the compensation committee of the board of directors, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common stock on the date of grant and the contractual term of stock option may not be greater than 10 years. Stock options granted to date typically vest over four years.

Stock Option Valuation

The assumptions used to determine the fair values of stock options granted to employees and directors are presented as follows:


	For the years ended December 31,
	2021	2020
Fair value of common stock	$5.72-17.00	$1.44-5.72
Dividend yield	—%	—%
Volatility	80.6%-91.25%	72.8%-80.6%
Risk-free interest rate	0.50%-1.33%	0.31%-1.46%
Expected term (years)	6.25	6.25

Summary of Option Activity

The Company’s stock option activity regarding employees, directors, and nonemployees is summarized as follows (in thousands excepts share and per share amounts):


	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate intrinsic value
Options outstanding—January 1, 2020		1,536,428		$	1.12		8.96	$	—
Granted		2,939,809			3.92
Exercised		(1,629,276	)		1.00
Cancelled		(1,809	)		0.93
Forfeited		(99,961	)		0.93
Options outstanding—December 31, 2020		2,745,185		$	4.20		9.40	$	4,183
Granted		1,076,022			9.19
Exercised		(149,707	)		2.12
Cancelled		(7,605	)		1.38
Forfeited		(20,099	)		5.79
Options outstanding—December 31, 2021		3,643,796		$	5.75		8.69	$	34,754
Options exercisable—December 31, 2021		958,921		$	3.90		8.19
Options vested and expected to vest—December 31, 2021		2,203,488		$	2.32		7.69

Additional information with regard to stock option activity involving employees and directors is as follows (in thousands except per share amounts):


	For the years ended December 31,
	2021		2020
Weighted-average grant-date fair value per option of total options granted	$	6.69	$	2.77
Aggregate intrinsic value of stock options exercised		1,616		961

As of December 31, 2021, total unrecognized compensation cost related to the unvested awards to employees, directors, and nonemployees is $11.5 million, which is expected to be recognized over a weighted-average period of 2.9 years.

Stock-Based Compensation

The Company recorded stock-based compensation expense regarding its employees, directors, and nonemployees as follows (in thousands):


	For the years ended December 31,
	2021		2020
Research and development expense	$	1,848	$	357
General and administrative expense		1,930		665
Total	$	3,778	$	1,022

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

The Company recorded no income tax benefit for the net loss incurred for the years ended December 31, 2021 and December 31, 2020, due to its uncertainty of realizing a benefit from such losses. All of the Company’s operating losses since inception have been generated in the United States.

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


	For the years ended December 31,
	2021			2020
Federal statutory rate		21.0	%		21.0	%
Federal research tax credit/orphan drug credit		(0.6	)%		(0.5	)%
Permanent items, including stock compensation		2.4	%		4.2	%
Change in valuation allowance		(21.9	)%		(26.8	)%
Other		(0.9	)%		2.2	%
		0.0	%		0.0	%

Significant components of the Company’s deferred tax assets are included in the table below (in thousands):


	For the years ended December 31,
	2021			2020
Deferred tax assets:
Net operating loss and capital loss carryforwards	$	20,815		$	10,586
Research and development credit carryforwards		2,359			1,196
Accrued expenses		1,377			400
Stock-based compensation		876			171
Total deferred tax assets		25,427			12,353
Deferred tax liabilities—depreciation		(80	)		(206	)
Less valuation allowance		(25,347	)		(12,147	)
Net deferred tax assets	$	—		$	—

The Company’s management has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are composed primarily of net operating loss (NOL) carryforwards and research and development credit carryforwards. Management has considered the Company’s history of net losses incurred since inception and probability of future losses to conclude it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. As a result, the Company has established a valuation allowance for the full amount of the net deferred tax assets as of December 31, 2021 and December 31, 2020. The valuation allowance increased by $13.2 million and $6.5. million during the years ended December 31, 2021 and December 31, 2020, respectively.

As of December 31, 2021, the Company has $78.0 million of US federal NOLs and $80.2 million of Kentucky state NOL carryforwards that have no expiration dates. The Company has $0.1 million in US federal and state capital loss carryforwards that expire in 2023. In addition, the Company had a US federal research and development tax credit carryforward of $2.4 million, which may be available to reduce future tax liabilities which start to expire in 2039.

Through December 31, 2021, the Company has generated research and development tax credits but has not conducted a study to document the qualified activities. Such study may result in an adjustment to the Company’s research and development credit carryforwards. Since a full valuation allowance has been provided against the Company’s research and development

credits, any reduction in the gross deferred tax asset established for the research and development credit carryforwards would not result in any net impact to the Company’s financial statements.

Realization of the future tax benefits is dependent on many factors, including the Company’s ability to generate taxable income within the NOL carryforward period. Under the provisions of Sections 382 and 383 of the Internal Revenue Code ("IRC"), and corresponding provisions of state law, certain substantial changes in the Company’s ownership, including a sale of the Company or significant changes in ownership due to sales of equity, may have limited, or may limit in the future, the amount of NOL carryforwards, which could be used annually to offset future taxable income. No study has been completed as of the date of these financial statements to determine whether a change in control, as defined by Section 382 of the IRC, has occurred. If it is determined the Company has experienced a change in control at any time since inception, realization of the NOL carryforwards or research and development tax credit carryforwards may be subject to an annual limitation. Any limitation may result in the expiration of a portion of NOL or research and development tax credit carryforwards before they are realized.

The Company files US federal and state tax returns in the United States. All tax years since incorporation remain open to examination by the major taxing jurisdictions (state and federal) to which the Company is subject, as carryforward attributes generated in years past may still be adjusted upon examination by the Internal Revenue Service (IRS) or other authorities if they have or will be used in a future period. The Company is not currently under examination by the IRS or any other jurisdictions for any tax year.

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

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

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

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

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

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

+ Details

Defined Contribution Plan

12 Months Ended

Dec. 31, 2021

Compensation And Retirement Disclosure [Abstract]

Defined Contribution Plan

13. Defined Contribution Plan

The Company established a defined contribution savings plan under Section 401(k) of the Internal Revenue Code. This plan covers substantially all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis. Company contributions to the plan are made to employees who meet minimum service requirements in the amount of 3% of gross pay, subject to certain limitations. For the years ended December 31, 2021 and December 31, 2020, the Company made contributions in the amount of $0.4 million and $0.2 million, respectively.

Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

14. Net Loss Per Share Attributable to Common Stockholders

Net Loss Per Share

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands except share and per share amounts).


	For the years ended December 31,
	2021			2020
Net loss and net loss attributable to common stockholders	$	(47,833	)	$	(22,707	)
Net loss per share attributable to common stockholders, basic and diluted	$	(1.64	)	$	(3.40	)
Weighted average number of common shares outstanding used in computation of net loss per common share, basic and diluted		29,126,373			6,685,066

The Company’s potential dilutive securities, which include convertible preferred stock, contingent stock liabilities, restricted stock related to early exercise of common stock options and common stock options, have been excluded from the computation of diluted net loss per share as the effect would be antidilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The following potential dilutive securities, presented on an as converted basis, were excluded from the calculation of net loss per share due to their anti-dilutive effect:


	For the years ended December 31,
	2021		2020
Convertible preferred shares (as converted to common stock and non-voting common stock)		—		24,392,498
Options to purchase common stock		3,643,796		2,745,185
Restricted stock related to early exercise of options to purchase common stock		538,340		932,279
Contingent common stock (as converted to common stock)		—		65,186
		4,182,136		28,135,148

Related Party Transactions

12 Months Ended

Dec. 31, 2021

Related Party Transactions

15. Related Party Transactions

The Company engaged a firm managed by a former executive of the company for professional services related to accounting, finance and other administrative functions. The costs incurred under this arrangement totaled $0.1 million and $0.4 million for the years ended December 31, 2021 and 2020, respectively, which were recorded as general and administrative expense in the accompanying statements of operations. As of December 31, 2021, there were no amounts owed under this arrangement.

Subsequent Events

12 Months Ended

Dec. 31, 2021

Subsequent Events [Abstract]

Subsequent Events

16. Subsequent Events

The Company has evaluated subsequent events through March 17, 2022, the date the financial statements were available to be issued. The Company has concluded no subsequent events have occurred that require disclosure, except for those referenced below.

Leases

On February 28, 2022, the Company entered into an amended lease agreement for office space in Wellesley, Massachusetts on substantially the same terms as reflected in Note 8, but for minor alterations to the improvements to be completed by the landlord. These alterations will be an additional obligation for the Company. These are not expected to be material to the financial statements.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2021
Summary Of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (US GAAP).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with US GAAP requires management to make judgments, assumptions, and estimates that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of financial statements, and the reported amounts of income and expense during the reporting period. The most significant estimates relate to the determination of fair value of the Company’s common stock, determination of the fair value of stock option grants and estimates related to the amount of accrued research and development expenses as of the balance sheet date. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, and makes adjustments when the facts and circumstances dictate. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2021 and 2020, cash consists primarily of checking and savings deposits and money market fund holdings.
Marketable Securities	Marketable Securities The Company classifies its marketable securities as available-for-sale securities, which are carried at their fair value based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive loss, a separate component of stockholders’ deficit. Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Equipment and furniture and fixtures are depreciated over five or seven year lives. Leasehold improvements are amortized over the shorter of the lease term or the five-year estimated useful life of the asset. Computer equipment and computer software are depreciated over three years. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in loss from operations. Expenditures for repairs and maintenance are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates its long-lived assets, which consist primarily of property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. No impairments have been identified as of December 31, 2021 and 2020.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. The Company’s investment policy includes guidelines regarding the quality of the financial institutions and financial instruments and defines allowable investments that it believes minimizes the exposure to concentration of credit risk. The Company may invest in money market funds (minimum of $1 billion in assets), U.S. Treasury securities, corporate debt, bank debt, U.S. government-related agency securities, other sovereign debt, municipal debt and commercial paper. These deposits may exceed federally insured limits. The Company has not experienced any losses historically in these accounts and believes that it is not exposed to significant credit risk as our deposits are held at financial institutions that management believes to be of high credit quality.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that the Company would receive to sell an investment in a timely transaction or pay to transfer a liability in a timely transaction with an independent buyer in the principal market, or in the absence of a principal market, the most advantageous market for the investment or liability. A framework is used for measuring fair value utilizing a three-tier hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 investments) and the lowest priority to unobservable inputs (Level 3 investments). The three levels of the fair value hierarchy are as follows: • Level 1 inputs: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2 inputs: Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and, • Level 3 inputs: Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. Financial instruments are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment and considers factors specific to the investment. The Company’s money market funds and marketable securities are carried at fair value determined according to the fair value hierarchy described above (Level 1 and Level 2, respectively). The Company’s contingent stock liability as of December 31, 2020 (see Note 3) is carried at fair value determined according to the fair value hierarchy described above (Level 3).
Research and Development Expenses	Research and Development Expenses Research and development expenses include (i) employee-related expenses, including salaries, benefits, travel and stock-based compensation expense; (ii) external research and development expenses incurred under arrangements with third parties, such as contract research organization agreements, investigational sites, and consultants; (iii) the cost of acquiring, developing, and manufacturing clinical study materials; (iv) costs associated with preclinical and clinical activities and regulatory operations; (v) costs incurred in development of intellectual property; and (vi) an allocated portion of facilities and other infrastructure costs associated with our research and development activities. Costs incurred in connection with research and development activities are expensed as incurred. The Company enters into consulting, research, and other agreements with commercial entities, researchers, universities, and others for the provision of goods and services. Such arrangements are generally cancelable upon reasonable notice and payment of costs incurred. Costs are considered incurred based on an evaluation of the progress to completion of specific tasks under each contract using information and data provided by the respective vendors, including the Company’s clinical sites. These costs consist of direct and indirect costs associated with specific projects, as well as fees paid to various entities that perform certain research on behalf of the Company. Depending upon the timing of payments to the service providers, the Company recognizes prepaid expenses or accrued expenses related to these costs. These accrued or prepaid expenses are based on management’s estimates of the work performed under service agreements, milestones achieved, and experience with similar contracts. The Company monitors each of these factors and adjusts estimates accordingly.
Stock-Based Compensation	Stock-Based Compensation The Company measures all stock options and other stock-based awards granted to employees, nonemployees, and directors based on the fair value on the date of the grant and recognizes stock-based compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues stock option awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company’s policy is to account for forfeitures when they occur. The Company classifies stock-based compensation expense in its statement of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipients’ service payments are classified. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company recently completed its IPO 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 it has adequate historical data regarding the volatility of its own traded stock price. 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 expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the US 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 zero because the Company has never paid cash dividends on common stock and does not expect to pay any cash dividends in the foreseeable future. Prior to the Company’s IPO, the Company considered the estimated fair value of the common stock as of the measurement date in determining the exercise price for options granted. The estimated fair value of the common stock was determined at each grant date based upon a variety of factors, including the illiquid nature of the common stock, arm’s-length sales of the Company’s capital stock (including convertible preferred stock), the effect of the rights and preferences of the preferred shareholders, and the prospects of a liquidity event. Among other factors are the Company’s financial position and historical financial performance, forecasted future operations of the Company, an evaluation or benchmark of the Company’s competition, and the current business climate in the marketplace. Significant changes to the key assumptions underlying the factors used could result in different fair values of common stock at each valuation date. The fair value for options granted since the Company’s IPO are based on the closing stock price on grant date.
Income Taxes	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 tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. 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. The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions. These reserves are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of income tax expense. The Company had no significant uncertain tax positions as of December 31, 2021 and December 31, 2020.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share The Company calculates basic and diluted net loss per share using the two-class method. The two-class method requires income available to common stockholders for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. The Company’s Series A convertible preferred stock, Series A-1 convertible preferred stock and Series B convertible preferred stock are participating securities. These participating securities do not contractually require the holders of such shares to participate in the Company’s losses. As such, net losses for the years presented were not allocated to the Company’s participating securities. Accordingly, basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares outstanding during the period plus the dilutive effects of potentially dilutive securities outstanding during the period. Potentially dilutive securities include vested and unexercised stock options, restricted stock issued upon early exercise of stock options, convertible preferred shares and contingent stock liabilities. The dilutive effect of stock options and contingent stock liabilities are computed using the treasury stock method and the dilutive effect of convertible preferred shares is calculated using the if-converted method. The Company has generated a net loss for all periods presented, therefore diluted net loss per share is the same as basic net loss per share since the inclusion of potentially dilutive securities would be anti-dilutive.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is made available and is regularly evaluated by the chief operating decision maker (“CODM”) in making decisions regarding resource allocation and assessing performance. The Company’s CODM is the chief executive officer and operations are managed as a single segment for the purposes of assessing performance and making operating decisions.
Comprehensive Loss	Comprehensive Loss Comprehensive loss represents net loss for the period plus the results of certain other changes in stockholders’ equity (deficit). The Company’s comprehensive loss included unrealized gains related to marketable securities for the years ended December 31, 2021 and 2020.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments—Credit Losses, (“ASC 326”), which introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The new model will apply to (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost; (2) loan commitments and certain other off-balance-sheet credit exposures; (3) debt securities and other financial assets measured at fair value through other comprehensive income; and (4) beneficial interests in securitized financial assets. The adoption of ASC 326 in January 2021 had no material impact on the Company’s financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which eliminates the current tests for lease classification under U.S. GAAP and requires lessees to recognize the right-to-use assets and related lease liabilities in the balance sheet. The new standard provides for a modified retrospective application. ASU 2016-02 is effective for interim and annual period beginning after December 15, 2021. The Company plans to adopt ASU 2016-02 on January 1, 2022. The Company expects to elect the package of practical expedients permitted under the transition guidance within the new standard, which, among other things, allows the Company to carry forward historical lease classification. The Company is completing its evaluation of the impact of adoption of ASU 2016-02 on its financial statements and expects to recognize a lease liability and related right-of-use assets on its balance sheet of approximately $3.4 million. The Company does not expect the standard to have a material impact on its results of operations or cash flows. In addition, the Company is currently implementing changes to processes and controls to support lease accounting and related disclosures under the new standard. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (ASC 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. ASU No. 2018-13 removes certain disclosures, modifies certain disclosures, and adds additional disclosures. ASU No. 2018-13 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. The adoption of ASU 2018-13 in January 2020 had no material impact on the Company’s financial statements.

Fair Value of Financial Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis


	December 31, 2021
	Total		Level 1		Level 2		Level 3
Financial assets:
Money market funds (cash equivalents)	$	10,319	$	10,319	$	—	$	—
Marketable securities		225,357		27,186		198,171		—
Total financial assets measured at fair value	$	235,676	$	37,505	$	198,171	$	—


	December 31, 2020
	Total		Level 1		Level 2		Level 3
Financial assets:
Money market funds (cash equivalents)	$	13,943	$	13,943	$	—	$	—
Marketable securities		131,899		11,169		120,730		—
Total financial assets measured at fair value	$	145,842	$	25,112	$	120,730	$	—
Financial liabilities:
Contingent stock liability	$	373	$	—	$	—	$	373
Total financial liabilities measured at fair value	$	373	$	—	$	—	$	373

Schedule of Contingent Common Stock Liability Measured at Fair Value

A rollforward of the contingent common stock liability, which is measured at fair value for the years ended December 31, 2021 and 2020, is represented as follows (in thousands):


Fair value as of January 1, 2020	$	63
Change in fair value		310
Fair value as of December 31, 2020		373
Change in fair value		735
Share issuance in partial settlement of contingent stock		(831	)
Cash payment in partial settlement of contingent stock		(277	)
Fair value as of December 31, 2021	$	—

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2021

Marketable Securities [Abstract]

Summary of Company's Investments

The following table summarizes the Company’s investments (in thousands):


	December 31, 2021
	Amortized Cost		Unrealized Gain		Unrealized (Loss)			Estimated Fair Value
Commercial paper	$	179,151	$	38	$	(47	)	$	179,142
Corporate debt securities		31,244		—		(58	)		31,186
Government and agency securities		15,040		—		(11	)		15,029
Total	$	225,435	$	38	$	(116	)	$	225,357

Prepaid and Other Current Assets (Tables)

12 Months Ended

Dec. 31, 2021

Prepaid Expense And Other Assets Current [Abstract]

Summary of Prepaid and Other Current Assets

Prepaid and other current assets consisted of the following (in thousands):


	December 31,
	2021		2020
Prepaid insurance	$	1,121	$	102
Prepaid research and development expenses		782		702
Other current assets		640		459
Total prepaid and other current assets	$	2,543	$	1,263

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2021

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	December 31,
	2021			2020
Equipment	$	4,449		$	2,666
Leasehold improvements		821			580
Computer equipment		953			264
Furniture and fixtures		426			255
Construction in progress		952			491
Total property and equipment		7,601			4,256
Less accumulated depreciation		(2,797	)		(2,243	)
Property and equipment, net	$	4,804		$	2,013

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2021

Accrued Liabilities Current [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following (in thousands):


	December 31,
	2021		2020
Compensation and benefit costs	$	3,320	$	1,400
Research and development expenses		854		788
Professional fees, consulting and other		1,257		449
Total accrued expenses	$	5,431	$	2,637

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rent Payments


Years Ending December 31,
2022	$	907
2023	$	1,065
2024	$	937
2025	$	700
2026 and beyond	$	437
Total	$	4,046

Common Stock (Table)

12 Months Ended

Dec. 31, 2021

Stockholders Equity Note [Abstract]

Schedule of Common Stock Reserved


	December 31,
	2021		2020
Conversion of Series A Preferred Stock		—		7,476,632
Conversion of Series A-1 Preferred Stock		—		5,233,637
Conversion of Series B Preferred Stock		—		11,682,229
Restricted stock related to early exercise of common stock options		538,340		932,279
Outstanding common stock options		3,643,796		2,745,185
Shares reserved for issuance under equity incentive plans		2,702,995		1,143,820
Shares reserved for issuance under the 2021 Employee Stock Purchase Plan		837,088		—
Contingent stock		—		65,186
Total		7,722,219		29,278,968

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Assumptions Used to Determine the Fair Values of Stock Options Granted

The assumptions used to determine the fair values of stock options granted to employees and directors are presented as follows:


	For the years ended December 31,
	2021	2020
Fair value of common stock	$5.72-17.00	$1.44-5.72
Dividend yield	—%	—%
Volatility	80.6%-91.25%	72.8%-80.6%
Risk-free interest rate	0.50%-1.33%	0.31%-1.46%
Expected term (years)	6.25	6.25

Summary of Option Activity

The Company’s stock option activity regarding employees, directors, and nonemployees is summarized as follows (in thousands excepts share and per share amounts):


	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate intrinsic value
Options outstanding—January 1, 2020		1,536,428		$	1.12		8.96	$	—
Granted		2,939,809			3.92
Exercised		(1,629,276	)		1.00
Cancelled		(1,809	)		0.93
Forfeited		(99,961	)		0.93
Options outstanding—December 31, 2020		2,745,185		$	4.20		9.40	$	4,183
Granted		1,076,022			9.19
Exercised		(149,707	)		2.12
Cancelled		(7,605	)		1.38
Forfeited		(20,099	)		5.79
Options outstanding—December 31, 2021		3,643,796		$	5.75		8.69	$	34,754
Options exercisable—December 31, 2021		958,921		$	3.90		8.19
Options vested and expected to vest—December 31, 2021		2,203,488		$	2.32		7.69

Summary of Additional Information to Stock Option Activity Involving Employees and Directors

Additional information with regard to stock option activity involving employees and directors is as follows (in thousands except per share amounts):


	For the years ended December 31,
	2021		2020
Weighted-average grant-date fair value per option of total options granted	$	6.69	$	2.77
Aggregate intrinsic value of stock options exercised		1,616		961

Summary of Stock-based Compensation Expense

The Company recorded stock-based compensation expense regarding its employees, directors, and nonemployees as follows (in thousands):


	For the years ended December 31,
	2021		2020
Research and development expense	$	1,848	$	357
General and administrative expense		1,930		665
Total	$	3,778	$	1,022

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Summary of Reconciliation of U.S. Federal Statutory Income Tax Rate

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


	For the years ended December 31,
	2021			2020
Federal statutory rate		21.0	%		21.0	%
Federal research tax credit/orphan drug credit		(0.6	)%		(0.5	)%
Permanent items, including stock compensation		2.4	%		4.2	%
Change in valuation allowance		(21.9	)%		(26.8	)%
Other		(0.9	)%		2.2	%
		0.0	%		0.0	%

Summary of Significant Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets are included in the table below (in thousands):


	For the years ended December 31,
	2021			2020
Deferred tax assets:
Net operating loss and capital loss carryforwards	$	20,815		$	10,586
Research and development credit carryforwards		2,359			1,196
Accrued expenses		1,377			400
Stock-based compensation		876			171
Total deferred tax assets		25,427			12,353
Deferred tax liabilities—depreciation		(80	)		(206	)
Less valuation allowance		(25,347	)		(12,147	)
Net deferred tax assets	$	—		$	—

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands except share and per share amounts).


	For the years ended December 31,
	2021			2020
Net loss and net loss attributable to common stockholders	$	(47,833	)	$	(22,707	)
Net loss per share attributable to common stockholders, basic and diluted	$	(1.64	)	$	(3.40	)
Weighted average number of common shares outstanding used in computation of net loss per common share, basic and diluted		29,126,373			6,685,066

Summary of Potential Dilutive Securities Excluded From Calculation of Net Loss Per Share Due to Anti-dilutive Effect

The following potential dilutive securities, presented on an as converted basis, were excluded from the calculation of net loss per share due to their anti-dilutive effect:


	For the years ended December 31,
	2021		2020
Convertible preferred shares (as converted to common stock and non-voting common stock)		—		24,392,498
Options to purchase common stock		3,643,796		2,745,185
Restricted stock related to early exercise of options to purchase common stock		538,340		932,279
Contingent common stock (as converted to common stock)		—		65,186
		4,182,136		28,135,148

Nature of Business and Liquidity - Additional Information (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	May 11, 2021 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Underwriting discounts and commissions and other expenses		$ 12,858,764
Preferred stock outstanding \| shares	0	0
Reverse stock split ratio	0.1869
Net loss		$ 47,833	$ 22,707
Cash used for operation		39,988	19,212
Accumulated deficit		90,847	43,014
Cash and cash equivalents		18,614	$ 17,589
Marketable securities		$ 225,400
Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Offering price \| $ / shares		$ 17.00
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold \| shares		8,825,000
Underwriting discounts and commissions and other expenses		$ 2,369
Common Stock \| Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold \| shares	8,825,000
Offering price \| $ / shares	$ 17.00
Gross proceeds from sale of shares	$ 150,000
Underwriting discounts and commissions and other expenses	$ 12,900

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2022
Summary Of Significant Accounting Policies [Line Items]
Impairments of long-lived assets	$ 0	$ 0
Expected dividend yield	0.00%
Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Right-of-use assets			$ 3,400,000
Lease liability			$ 3,400,000
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Property, plant and equipment, useful life	amortized over the shorter of the lease term or the five-year estimated useful life of the asset
Computer Equipment and Computer Software
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Minimum \| Money Market Funds
Summary Of Significant Accounting Policies [Line Items]
Investment in assets	$ 1,000,000,000
Minimum \| Equipment and Furniture and Fixtures
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Maximum \| Equipment and Furniture and Fixtures
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	7 years

Fair Value of Financial Assets and Liabilities - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets:
Total financial assets measured at fair value	$ 235,676	$ 145,842
Financial liabilities:
Total financial liabilities measured at fair value		373
Cash Equivalents
Financial assets:
Total financial assets measured at fair value	10,319
Money Market Funds \| Cash Equivalents
Financial assets:
Total financial assets measured at fair value		13,943
Marketable Securities
Financial assets:
Total financial assets measured at fair value	225,357	131,899
Level 1
Financial assets:
Total financial assets measured at fair value	37,505	25,112
Level 1 \| Cash Equivalents
Financial assets:
Total financial assets measured at fair value	10,319
Level 1 \| Money Market Funds \| Cash Equivalents
Financial assets:
Total financial assets measured at fair value		13,943
Level 1 \| Marketable Securities
Financial assets:
Total financial assets measured at fair value	27,186	11,169
Level 2
Financial assets:
Total financial assets measured at fair value	198,171	120,730
Level 2 \| Marketable Securities
Financial assets:
Total financial assets measured at fair value	$ 198,171	120,730
Level 3
Financial liabilities:
Total financial liabilities measured at fair value		373
Contingent Stock Liability
Financial liabilities:
Total financial liabilities measured at fair value		373
Contingent Stock Liability \| Level 3
Financial liabilities:
Total financial liabilities measured at fair value		$ 373

Fair Value of Financial Assets and Liabilities - Additional Information (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 UsdPerShares shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Number of shares equal to fair value of contingent equity consideration		65,186
Common stock, shares issued	16,297	16,297	7,087,130
Cash payment for contingent equity settlement \| $		$ 277
Measurement Input, Share Price
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of common stock used to value contingent stock liability \| UsdPerShares			5.72
IPO
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Common stock, shares issued	48,889	48,889
Cash payment for contingent equity settlement \| $	$ 300
Shares issued, price per share \| $ / shares		$ 17.00

Fair Value of Financial Assets and Liabilities - Schedule of Contingent Common Stock Liability Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair value, Beginning balance	$ 373	$ 63
Change in fair value	735	310
Share issuance in partial settlement of contingent stock	(831)
Cash payment in partial settlement of contingent stock	277
Fair value, Ending balance	$ 0	$ 373

Prepaid and Other Current Assets - Summary of Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Prepaid insurance	$ 1,121	$ 102
Prepaid research and development expenses	782	702
Other current assets	640	459
Total prepaid and other current assets	$ 2,543	$ 1,263

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 7,601	$ 4,256
Less accumulated depreciation	(2,797)	(2,243)
Property and equipment, net	4,804	2,013
Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	4,449	2,666
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	821	580
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	953	264
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	426	255
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 952	$ 491

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation expense	$ 0.6	$ 0.4

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Compensation and benefit costs	$ 3,320	$ 1,400
Research and development expenses	854	788
Professional fees, consulting and other	1,257	449
Total accrued expenses	$ 5,431	$ 2,637

Commitments and Contingencies - Additional Information (Details)		1 Months Ended						12 Months Ended
	Oct. 31, 2018 USD ($) shares	Sep. 30, 2021	Jul. 31, 2021	May 31, 2021 USD ($) shares	Feb. 28, 2021 USD ($)	Jun. 30, 2020 USD ($)	Feb. 29, 2020 USD ($)	Dec. 31, 2021 USD ($) Leaseagreement shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Number of active lease agreements \| Leaseagreement								6
Lessee, operating lease, existence of option to extend								true
Lease option to extend								three additional years
Lease termination date								Nov. 30, 2023
Lease term period								39 months
Rent expense								$ 700,000	$ 600,000
Common stock issued \| shares				16,297				16,297	7,087,130
Cash payment for contingent equity settlement								$ 277,000
Contingent stock liability								$ 0	$ 373,000	$ 63,000
Annual maintenance fee pursuant to license agreement					$ 100,000		$ 100,000
Research and Development Expense
Loss Contingencies [Line Items]
Milestone payment						$ 100,000
IPO
Loss Contingencies [Line Items]
Common stock issued \| shares				48,889				48,889
Cash payment for contingent equity settlement				$ 300,000
Other Liabilities
Loss Contingencies [Line Items]
Contingent stock liability									$ 400,000
ULRF License Agreement
Loss Contingencies [Line Items]
Percentage of compensation on net sales of all licensed products sold	3.00%
Compensation on non-royalty sublicensing income								one third
Common stock issued \| shares	65,186
ULRF License Agreement \| Contingent Equity Consideration
Loss Contingencies [Line Items]
Common stock issued \| shares	65,186
ULRF License Agreement \| Maximum
Loss Contingencies [Line Items]
Compensation on regulatory and sales milestones	$ 1,625,000
Kentucky
Loss Contingencies [Line Items]
Lease termination date		Nov. 30, 2023						Dec. 31, 2021
Wellesley
Loss Contingencies [Line Items]
Lease commencement date								Apr. 30, 2021
Massachusetts
Loss Contingencies [Line Items]
Lease termination date								Mar. 31, 2021
Houston, Texas
Loss Contingencies [Line Items]
Lessee, operating lease, existence of option to extend			true
Lease option to extend								option to extend on a month-to-month basis at the end of the original term.
Lease termination date			Dec. 31, 2021
Term of lease not yet commenced			36 months
Lease commencement date			Jan. 31, 2022
Lease term period			5 months

Commitments and Contingencies - Summary of Future Minimum Rent Payments (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Operating Lease Liabilities Payments Due Rolling Maturity [Abstract]
2022	$ 907
2023	1,065
2024	937
2025	700
2026 and beyond	437
Total	$ 4,046

Convertible Preferred Stock - Additional Information (Details) - USD ($)	1 Months Ended				12 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Dec. 31, 2019	Nov. 30, 2018	Dec. 31, 2021	Dec. 31, 2020	May 31, 2021
Convertible Preferred Stock [Line Items]
Issuance costs, incurred					$ 12,858,764,000
Product interest rights held					After the first commercial sale of product, the product interest right entitles the holders to a product interest payment for each product interest right held equal to 1/48,000,000 multiplied by 9% of net product sales on a territory-by-territory basis. If the Company enters into a license of rights to develop and/or commercialize a product, the holder is entitled to a product interest payment for each product interest right equal to 1/48,000,000 multiplied by 30% of licensing income.
Remaining product interest rights outstanding					0.00%
Non-voting Common Stock
Convertible Preferred Stock [Line Items]
Conversion of preferred stock							1,150,000
Common Stock
Convertible Preferred Stock [Line Items]
Issuance costs, incurred					$ 2,369,000
Conversion of preferred stock							10,532,229
Tranche 2
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued			16,000,000
Tranche 3
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued		12,000,000
Series A Convertible Preferred Stock
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued				22,500,000	0	40,000,000
Shares issued, price per share				$ 1.00	$ 1.00
Proceeds from issuance of convertible preferred stock				$ 22,500,000
Issuance costs, incurred				$ 2,000,000.0
Preferred stock, shares outstanding			40,000,000		0	40,000,000
Conversion price					$ 5.35
Series A Convertible Preferred Stock \| Common Stock
Convertible Preferred Stock [Line Items]
Conversion of preferred stock							7,476,632
Series A Convertible Preferred Stock \| Tranche 2
Convertible Preferred Stock [Line Items]
Shares issued, price per share			$ 1.00
Proceeds from issuance of convertible preferred stock			$ 17,500,000
Preferred stock, additional shares issued			17,500,000
Series A-1 Convertible Preferred Stock
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued					0	28,000,000
Shares issued, price per share				$ 1.25	$ 1.25
Preferred stock, shares outstanding			16,000,000		0	28,000,000
Conversion price					$ 6.69
Series A-1 Convertible Preferred Stock \| Common Stock
Convertible Preferred Stock [Line Items]
Conversion of preferred stock							5,233,637
Series A-1 Convertible Preferred Stock \| Tranche 2
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued			16,000,000
Shares issued, price per share			$ 1.25
Proceeds from issuance of convertible preferred stock			$ 20,000,000.0
Issuance costs, incurred			$ 1,300,000
Preferred stock, shares outstanding			16,000,000
Series A-1 Convertible Preferred Stock \| Tranche 3
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued		12,000,000
Shares issued, price per share		$ 1.25
Proceeds from issuance of convertible preferred stock		$ 15,000,000.0
Preferred stock, shares outstanding		12,000,000
Series B Convertible Preferred Stock
Convertible Preferred Stock [Line Items]
Preferred stock, shares issued	62,499,993				0	62,499,993
Shares issued, price per share	$ 1.84				$ 1.84
Proceeds from issuance of convertible preferred stock	$ 115,000,000.0
Issuance costs, incurred	$ 500,000
Preferred stock, shares outstanding					0	62,499,993
Conversion price					$ 9.84
Convertible Preferred Stock
Convertible Preferred Stock [Line Items]
Dividends declared					$ 0	$ 0
Dividends paid					0	$ 0
Convertible Preferred Stock \| Minimum
Convertible Preferred Stock [Line Items]
Proceeds from issuance of convertible preferred stock					$ 60,000,000
Offering price per share					$ 9.84

Common Stock (Additional Information) (Details) - $ / shares	Dec. 31, 2021	May 11, 2021	Apr. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Authorization of undesignated preferred stock			10,000,000
Undesignated preferred stock, par value			$ 0.0001
Undesignated preferred stock, outstanding	0	0
Common stock, shares authorized	140,000,000			36,366,101
Voting Shares
Class Of Stock [Line Items]
Common stock, shares authorized			140,000,000
Non-voting Shares
Class Of Stock [Line Items]
Common stock, shares authorized	10,000,000		10,000,000

Common Stock - Schedule of Common Stock Reserved (Details) - shares	Dec. 31, 2021	May 31, 2021	Apr. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Outstanding common stock options	3,643,796			2,745,185	1,536,428
2021 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Shares reserved for issuance			852,971
Common Stock
Class Of Stock [Line Items]
Conversion of preferred stock		10,532,229
Restricted stock related to early exercise of common stock options	538,340			932,279
Outstanding common stock options	3,643,796			2,745,185
Contingent stock				65,186
Total	7,722,219			29,278,968
Common Stock \| Series A Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock				7,476,632
Common Stock \| Series A-1 Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock				5,233,637
Common Stock \| Series B Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock				11,682,229
Common Stock \| Equity Incentive Plans
Class Of Stock [Line Items]
Shares reserved for issuance	2,702,995			1,143,820
Common Stock \| 2021 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Shares reserved for issuance	837,088

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, shares		3,643,796	2,745,185	1,536,428
Contractual term of stock option		8 years 8 months 8 days	9 years 4 months 24 days	8 years 11 months 15 days
Unrecognized compensation cost		$ 11.5
Unrecognized compensation cost, expected to be recognized period		2 years 10 months 24 days
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares remained available for future grant	6,397,289	2,702,995
Options outstanding, shares		3,569,030
Percentage of fair market value of common stock		100.00%
Stock options vesting period		4 years
2021 Equity Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized under the plan	3,015,907
Contractual term of stock option		10 years
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares remained available for future grant	3,381,382
Options outstanding, shares		3,569,030
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Discount percentage to purchase shares	15.00%
Offering periods	6 months
Increment in number of shares authorized possible	3,000,000
Number of shares authorized under the plan	852,971
Percentage of cumulative number of shares of common stock issued and outstanding	1.00%

Stock-Based Compensation - Schedule of Assumptions Used to Determine the Fair Values of Stock Options Granted (Details) - Stock Option - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, minimum	80.60%	72.80%
Volatility, maximum	91.25%	80.60%
Risk-free interest rate, minimum	0.50%	0.31%
Risk-free interest rate, maximum	1.33%	1.46%
Expected term (years)	6 years 3 months	6 years 3 months
Common Stock \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of common stock	$ 5.72	$ 1.44
Common Stock \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of common stock	$ 17.00	$ 5.72

Stock-Based Compensation - Summary of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award Additional General Disclosures [Abstract]
Options outstanding, beginning balance, shares	2,745,185	1,536,428
Granted, shares	1,076,022	2,939,809
Exercised, shares	(149,707)	(1,629,276)
Cancelled, shares	(7,605)	(1,809)
Forfeited, shares	(20,099)	(99,961)
Options outstanding, ending balance, shares	3,643,796	2,745,185	1,536,428
Options exercisable, shares	958,921
Options vested and expected to vest, shares	2,203,488
Options outstanding, weighted- average exercise price	$ 4.20	$ 1.12
Granted, weighted- average exercise price	9.19	3.92
Exercised, weighted- average exercise price	2.12	1.00
Cancelled, weighted-average exercise price	1.38	0.93
Forfeited, weighted- average exercise price	5.79	0.93
Options outstanding, weighted- average exercise price	5.75	$ 4.20	$ 1.12
Options exercisable, weighted- average exercise price	3.90
Options vested and expected to vest, weighted- average exercise price	$ 2.32
Options outstanding, weighted- average remaining contractual life	8 years 8 months 8 days	9 years 4 months 24 days	8 years 11 months 15 days
Options exercisable, weighted- average remaining contractual life	8 years 2 months 8 days
Options vested and expected to vest, weighted- average remaining contractual life	7 years 8 months 8 days
Options outstanding, aggregate intrinsic value	$ 34,754	$ 4,183

Stock-Based Compensation - Summary of Additional Information to Stock Option Activity Involving Employees and Directors (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Weighted-average grant-date fair value per option of total options granted	$ 6.69	$ 2.77
Aggregate intrinsic value of stock options exercised	$ 1,616	$ 961

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	$ 3,778	$ 1,022
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,848	357
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,930	$ 665

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Income tax benefit	$ 0	$ 0
Valuation allowance of net deferred tax asset, Increase (Decrease)	13,200,000	$ 6,500,000
Federal net operating loss carryforwards	78,000,000.0
US federal and state capital loss carryforwards	$ 100,000
Operating loss carryforwards expiration date	Dec. 31, 2023
US federal research and development tax credit carryforward	$ 2,400,000
Tax credit carryforward expiration date	Dec. 31, 2039
Kentucky
Income Tax Disclosure [Line Items]
Foreign net operating loss carryforwards	$ 80,200,000

Income Taxes - Summary of Reconciliation of U.S. Federal Statutory Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%
Federal research tax credit/orphan drug credit	(0.60%)	(0.50%)
Permanent items, including stock compensation	2.40%	4.20%
Change in valuation allowance	(21.90%)	(26.80%)
Other	(0.90%)	2.20%
Effective income tax rate reconciliation, percent	0.00%	0.00%

Income Taxes - Summary of Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss and capital loss carryforwards	$ 20,815	$ 10,586
Research and development credit carryforwards	2,359	1,196
Accrued expenses	1,377	400
Stock-based compensation	876	171
Total deferred tax assets	25,427	12,353
Deferred tax liabilities—depreciation	(80)	(206)
Less valuation allowance	$ (25,347)	$ (12,147)

Defined Contribution Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Contribution amount	$ 0.4	$ 0.2
Minimum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan minimum service requirements percentage	3.00%

Net Loss Per Share Attributable to Common Stockholders - Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Net loss and net loss attributable to common stockholders	$ (47,833)	$ (22,707)
Net loss per share attributable to common stockholders, basic and diluted	$ (1.64)	$ (3.40)
Weighted average number of common shares outstanding used in computation of net loss per common share, basic and diluted	29,126,373	6,685,066

- Definition

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

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+ Details

Net Loss Per Share Attributable to Common Stockholders - Summary of Potential Dilutive Securities Excluded From Calculation of Net Loss Per Share Due to Anti-dilutive Effect (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from calculation of net loss per share due to anti-dilutive effect	4,182,136	28,135,148
Convertible Preferred Shares (as Converted to Common Stock and Non-voting Common Stock)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from calculation of net loss per share due to anti-dilutive effect		24,392,498
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from calculation of net loss per share due to anti-dilutive effect	3,643,796	2,745,185
Restricted Stock Related to Early Exercise of Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from calculation of net loss per share due to anti-dilutive effect	538,340	932,279
Contingent Common Stock (as Converted to Common Stock)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from calculation of net loss per share due to anti-dilutive effect		65,186

Related Party Transactions - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Related Party Transactions [Abstract]
General and administrative expense	$ 100,000	$ 400,000
Amounts owed to related party	$ 0

- Definition

Carrying amount as of the balance sheet date of obligations due all related parties.

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+ Details

Label	Element	Value
Available For Sale Debt Securities Amortized Cost Basis	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis	$ 225,435,000
Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	38,000
Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	116,000
Available For Sale Securities Debt Securities	us-gaap_AvailableForSaleSecuritiesDebtSecurities	225,357,000
U S Government Agencies Debt Securities [Member]
Available For Sale Debt Securities Amortized Cost Basis	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis	15,040,000
Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	11,000
Available For Sale Securities Debt Securities	us-gaap_AvailableForSaleSecuritiesDebtSecurities	15,029,000
Commercial Paper [Member]
Available For Sale Debt Securities Amortized Cost Basis	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis	179,151,000
Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	38,000
Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	47,000
Available For Sale Securities Debt Securities	us-gaap_AvailableForSaleSecuritiesDebtSecurities	179,142,000
Corporate Debt Securities [Member]
Available For Sale Debt Securities Amortized Cost Basis	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis	31,244,000
Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	58,000
Available For Sale Securities Debt Securities	us-gaap_AvailableForSaleSecuritiesDebtSecurities	$ 31,186,000