0001789769-22-000008 | 10-K | XBRL Viewer

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CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 37,590	$ 241,714
Marketable securities	416,509	0
Prepaid expenses and other current assets	9,921	4,424
Total current assets	464,020	246,138
Property, plant and equipment, net	121,999	55,341
Intangibles	10,104	10,104
Goodwill	5,722	5,722
Other long-term assets	8,138	1,707
Total assets	609,983	319,012
Current liabilities:
Accounts payable	5,568	3,495
Accrued expenses and other current liabilities	34,449	8,402
Contingent consideration, current portion	1,341	1,384
Total current liabilities	41,358	13,281
Contingent consideration, net of current portion	10,980	10,893
Deferred tax liabilities	2,426	2,471
Other long-term liabilities	20	0
Total liabilities	54,784	26,645
Commitments and contingencies (Note 7)
Convertible preferred stock, par value $0.000001 per share; 10,000,000 and 74,350,598 shares authorized 0 and 70,176,046 shares issued and outstanding; $0 and $328,200 aggregate liquidation preference as of December 31, 2021, and 2020, respectively	0	331,966
Stockholders’ equity (deficit):
Common stock, par value $0.000001 per share; 300,000,000 and 111,000,000 shares authorized; 129,028,278 and 20,591,554 shares issued and outstanding as of December 31, 2021, and 2020, respectively	0	0
Additional paid-in capital	757,003	5,607
Accumulated other comprehensive loss	(87)	(283)
Accumulated deficit	(201,717)	(44,923)
Total stockholders’ equity (deficit)	555,199	(39,599)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 609,983	$ 319,012

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Convertible preferred stock, shares authorized (in shares)	10,000,000	74,350,598
Convertible preferred stock issued (in shares)	0	70,176,046
Convertible preferred stock outstanding (in shares)	0	70,176,046
Convertible preferred stock, liquidation preference	$ 0	$ 328,200,000
Common stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Common stock, shares authorized (in shares)	300,000,000	111,000,000
Common stock, shares issued (in shares)	129,028,278	20,591,554
Common stock, shares outstanding (in shares)	129,028,278	20,591,554

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Revenue	$ 0	$ 138
Operating expenses:
Research and development	107,251	19,399
General and administrative	48,309	14,383
Total operating expenses	155,560	33,782
Loss from operations	(155,560)	(33,644)
Other (expense), net	(1,195)	(3,943)
Loss before income tax expense	(156,755)	(37,587)
Income tax expense	(39)	(151)
Net loss	(156,794)	(37,738)
Other comprehensive income (loss):
Foreign currency translation	246	(283)
Unrealized loss on available-for-sale securities, net	(50)	0
Net comprehensive loss	$ (156,598)	$ (38,021)
Net loss per share, basic (in dollars per share)	$ (1.48)	$ (2.36)
Net loss per share, diluted (in dollars per share)	$ (1.48)	$ (2.36)
Weighted-average shares used in computing net loss per share, basic (in shares)	105,993,230	15,997,794
Weighted-average shares used in computing net loss per share, diluted (in shares)	105,993,230	15,997,794

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Series A	Series B	Series C	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019	15,000,000
Beginning balance at Dec. 31, 2019	$ 14,948
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of convertible preferred shares (in shares)		10,000,000	34,600,523	10,575,523
Issuance of convertible preferred shares		$ 14,366	$ 169,843	$ 132,809
Ending balance (in shares) at Dec. 31, 2020	70,176,046	25,000,000	34,600,523	10,575,523
Ending balance at Dec. 31, 2020	$ 331,966
Beginning balance (in shares) at Dec. 31, 2019					11,199,980
Beginning balance at Dec. 31, 2019	(6,892)				$ 0	$ 293	$ 0	$ (7,185)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with an acquisition (in shares)					5,640,000
Issuance of common stock in connection with an acquisition	3,243					3,243
Stock-based compensation	$ 1,706					1,706
Issuance of common stock from exercises of stock options (in shares)	591,824				3,751,574
Issuance of common stock from exercises of stock options	$ 365					365
Foreign currency translation	(283)						(283)
Net loss	(37,738)							(37,738)
Ending balance (in shares) at Dec. 31, 2020					20,591,554
Ending balance at Dec. 31, 2020	$ (39,599)				$ 0	5,607	(283)	(44,923)
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of convertible preferred shares (in shares)	4,174,551
Issuance of convertible preferred shares	$ 52,460
Conversion of redeemable convertible preferred stock (in shares)	(74,350,597)
Conversion of redeemable convertible preferred stock	$ (384,426)
Ending balance (in shares) at Dec. 31, 2021	0
Ending balance at Dec. 31, 2021	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 26,197					26,197
Issuance of common stock from exercises of stock options (in shares)	3,976,028				816,025
Issuance of common stock from exercises of stock options	$ 1,757					1,757
Foreign currency translation	246
Net loss	(156,794)							(156,794)
Issuance of common shares upon initial public offering net of underwriting discounts, commissions and offering costs (in shares)					18,400,000
Issuance of common shares upon initial public offering net of underwriting discounts, commissions and offering costs	339,016					339,016
Conversion of redeemable convertible preferred stock (in shares)					89,220,699
Conversion of redeemable convertible preferred stock	384,426					384,426
Other comprehensive income	196						196
Ending balance (in shares) at Dec. 31, 2021					129,028,278
Ending balance at Dec. 31, 2021	$ 555,199				$ 0	$ 757,003	$ (87)	$ (201,717)

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares
Series A
Shares issued, price per share (in dollars per share) \| $ / shares	$ 1.00
Issuance costs \| $	$ 34
Series B
Shares issued, price per share (in dollars per share) \| $ / shares	$ 4.92
Issuance costs \| $	$ 357
Series C
Shares issued, price per share (in dollars per share) \| $ / shares	$ 12.58
Issuance costs \| $	$ 191

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (156,794)	$ (37,738)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on issuance of Series A convertible preferred stock	0	4,400
Stock-based compensation	26,197	1,706
Foreign exchange remeasurement loss (gain)	710	(643)
Change in fair value of contingent consideration	294	928
Depreciation and amortization	2,752	256
Other, net	342	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(5,045)	(898)
Other long-term assets	(6,502)	(1,141)
Accounts payable	3,862	(1,054)
Accrued expenses and other current liabilities	12,046	4,568
Net cash used in operating activities	(122,138)	(29,616)
Cash flows from investing activities:
Purchase of marketable securities	(1,107,565)	0
Maturities of marketable securities	691,000	0
Purchases of property, plant and equipment	(57,831)	(50,816)
Business acquisition, net of cash acquired	0	(306)
Net cash used in investing activities	(474,396)	(51,122)
Cash flows from financing activities:
Proceeds from initial public offering, net of issuance costs	339,016	0
Proceeds from issuance of convertible preferred stock, net of issuance costs	52,460	312,618
Proceeds from exercise of stock options	1,757	365
Other financing activities	(69)	65
Net cash provided by financing activities	393,164	313,048
Net (decrease) increase in cash, cash equivalents, and restricted cash	(203,370)	232,310
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(304)	559
Cash, cash equivalents and restricted cash—beginning of period	241,764	8,895
Cash, cash equivalents and restricted cash—end of period	38,090	241,764
Supplemental disclosure of noncash information:
Conversion of preferred stock to common stock upon initial public offering	384,426	0
Purchases of property, plant and equipment in accounts payable and accrued liabilities	15,091	2,922
Business acquisition through issuance of common stock and contingent consideration payable	0	14,592
Deferred offering costs in accrued expenses and other current liabilities	$ 0	$ 516

Organization and Description of Business	12 Months Ended
Organization and Description of Business	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of BusinessInstil Bio Inc. (the “Company” or “Instil Bio”) is headquartered in Dallas, Texas and was incorporated in the state of Delaware in August 2018. The Company is a clinical-stage biopharmaceutical company focused on developing an innovative cell therapy pipeline of autologous tumor infiltrating lymphocyte (“TIL”) therapies for the treatment of patients with cancer. Principal operations commenced during the first quarter of 2019 when the Company in-licensed its foundational TIL technology.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries Instil Bio (UK) Ltd. (formerly Immetacyte Ltd. (“Immetacyte”)) and Complex Therapeutics, LLC. Immetacyte was acquired on March 2, 2020 and Complex Therapeutics, LLC was incorporated on October 14, 2020. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include but are not limited to the fair value of stock valuations prior to the Company's initial public offering, the fair value of acquired intangible assets, the fair value of contingent consideration payable, and the fair value of buildings and land in an asset acquisition. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates.

Concentration of Credit Risk

Financial Instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and marketable securities. The Company's cash and cash equivalents are held by two financial institutions in the United States ("U.S.") and one financial institution in the United Kingdom ("U.K."), which management believes to be financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions. At times, the Company's deposits held in the U.S. and U.K. may exceed the Federal Depository Insurance Corporation and Financial Services Compensation Scheme, respectively, insured limits. During the years ended December 31, 2021 and 2020, the Company has not experienced any credit losses in such accounts or marketable securities.

Risks and Uncertainties

The Company is subject to a number of risks similar to other development-stage biopharmaceutical companies, including but not limited to, dependency on the clinical and commercial success of its product candidates, ability to obtain regulatory approval of its product candidates, uncertainty of broad adoption of its approved products, if any, by physicians and patients, manufacturing, the need to obtain adequate additional funding, significant competition, and protection of its intellectual property portfolio.

Stock Split and Initial Public Offering

On March 12, 2021, the Company effected a 1.2-for-1 stock split of the Company’s common stock. The par value was not adjusted as a result of the stock split. The authorized shares as of March 12, 2021 were adjusted as a result of the stock split. All share and per share information included in the accompanying consolidated financial statements has been adjusted to reflect this stock split. The accompanying consolidated financial statements and notes thereto give retroactive effect to the stock split for all periods presented.

On March 23, 2021, the Company completed its initial public offering ("IPO") through an underwritten sale of an aggregate of 18,400,000 shares of its common stock at a price of $20.00 per share. The aggregate net proceeds from the offering, inclusive of an additional 2,400,000 common shares sold upon the full exercise of the underwriter's purchase option, after deducting underwriting discounts and commissions of $25.8 million and other offering expenses of $3.2 million, was $339.0 million.

Concurrent with the IPO, all then-outstanding shares of the Company's convertible preferred stock outstanding (see Note 8) were automatically converted into an aggregate of 89,220,699 shares of common stock and were reclassified into permanent equity. Further, immediately following the closing of the IPO, the Company amended and restated its certificate of incorporation such that the total number of shares of common stock authorized to be issued was 300,000,000 and the total number of shares of preferred stock authorized to be issued was 10,000,000. Following the IPO, there are no shares of convertible preferred stock outstanding.

COVID-19 Pandemic

On March 11, 2020, the World Health Organization characterized the outbreak of COVID-19 as a global pandemic and recommended containment and mitigation measures. Since then, extraordinary actions have been taken by international, federal, state, and local public health and governmental authorities to contain and combat the outbreak and spread of COVID-19 in regions throughout the world. These actions include travel bans, quarantines, “stay-at-home” orders and similar mandates for many individuals to substantially restrict daily activities and for many businesses to curtail or cease normal operations. As a result of COVID-19, the Company has taken precautionary measures in order to minimize the risk of the virus to its employees and the communities in which it operates. There has been minimal disruption in the Company’s ability to ensure the effective operation of its business. While the broader implications of the COVID-19 pandemic on the Company’s results of operations and overall financial performance remain uncertain, including any implications from the spread of the new Delta and Omicron variants of COVID-19, the COVID-19 pandemic has, to date, not had a material adverse impact on its results of operations or our ability to raise funds to sustain operations. The economic effects of the pandemic and resulting societal changes are currently not predictable, and the future financial impacts could vary from those foreseen.

Segments

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.

Cash, Cash Equivalents, Restricted Cash and Marketable Securities

The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents include amounts invested in money market accounts.

Restricted cash consists of a money market account which serves as collateral for the Company’s employee corporate credit cards and is classified within other long-term assets on the consolidated balance sheets.

Our short-term marketable securities have original maturities of less than a year at date of purchase. We classify and account for our marketable securities as available-for-sale securities, which are carried at their fair

values based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred. As of December 31, 2021, marketable securities consisted of U.S. Treasury bills. The Company had no holdings of marketable securities as of December 31, 2020.

Short-term marketable securities are recorded at their estimated fair value. We periodically review whether our securities may be other-than-temporarily impaired, including whether or not (i) we have the intent to sell the security or (ii) it is more likely than not that we will be required to sell the security before its anticipated recovery. If one of these factors is met, we will record an impairment loss associated with our impaired investment. The impairment loss will be recorded as a write-down of investments in the consolidated balance sheets and a realized loss within other expense in the consolidated statements of operations. For the year ended December 31, 2021, there were no impairment losses for the investments.

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the amounts shown in the consolidated statements of cash flows (in thousands):


	December 31,
	2021		2020
Cash and cash equivalents	$	37,590	$	241,714
Restricted cash	500		50
Cash, cash equivalents and restricted cash	$	38,090	$	241,764

Fair Value Measurement

Assets and liabilities recorded at fair value on a recurring basis in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value maximize the use of observable inputs and minimize the use of unobservable inputs. The Company measures fair value based on a three-tier hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows:

Level 1 —Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 2 —Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the assets or liabilities. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active.

Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

In determining fair value, the Company utilize quoted market prices, or valuation techniques that maximize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value.

Property, Plant and Equipment, Net

Property, plant and equipment, with the exception of land, is stated at cost less accumulated depreciation. Depreciation is computed on a straight-line basis over the estimated useful lives of the related assets. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated

depreciation are removed from the balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations and comprehensive loss. The estimated useful lives of the Company’s property, plant and equipment are as follows:

Laboratory equipment 7 years

Manufacturing equipment 7 years

Office and computer equipment 3 years

Leasehold improvements Shorter of remaining lease term or estimated useful life

The Company owns land and buildings that it is in the process of developing for its U.S. operations. As described in Note 3, the buildings are still in development and depreciation will commence once the clinical manufacturing facility is ready for its intended use. A variety of costs are incurred in the development of a property. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when the development project is substantially complete and placed into service to begin depreciation involves a degree of judgment. The costs of land and buildings under development include specifically identifiable costs. The capitalized costs include pre-construction costs essential to the development of the property, development costs, and construction costs. When the development project is substantially complete and available for occupancy, the Company ceases capitalization of costs other than costs to improve the functionality or extend the useful lives of property, plant and equipment included as part of the project.

Impairment of Long-Lived Assets

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or that the useful life is shorter than originally estimated. Recoverability of assets is measured by comparing the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset over its remaining useful life. If such assets are impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. If the useful life is shorter than originally estimated, the Company depreciates or amortizes the remaining carrying value over the revised shorter useful life. Assets to be disposed of by sale are reflected at the lower of their carrying amount or fair value less cost to sell.

Business Combinations

The Company evaluates acquisitions of assets and related liabilities and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs which would meet the requirements of a business.

The Company accounts for its business combinations using the acquisition method of accounting which requires recognition and measurement of all identifiable assets acquired and liabilities assumed at their full fair value as of the date it obtains control. The Company has determined the fair value of assets acquired and liabilities assumed based upon management's estimates of the fair values of assets acquired and liabilities assumed in the acquisitions. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable assets acquired. The Company accounts for contingent considerations at the acquisition-date fair value as part of the consideration transferred in the transactions.

While management has used its best estimates and assumptions to measure the fair value of the identifiable assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, not to exceed one year from the date of acquisition, any changes in the estimated fair values of the net assets recorded for the acquisition will result in an adjustment to goodwill. Upon the conclusion of the measurement period of final determination of the values of assets acquired or

liabilities assumed, whichever comes first, the Company records any subsequent adjustments to the consolidated statements of operations and comprehensive loss. Acquisition-related costs, such as legal and consulting fees, are expensed as incurred.

The Company accounts for an asset acquisition by recognizing net assets based on the cost to the acquiring entity on a relative fair value basis, which includes transaction costs in addition to consideration given. Goodwill is not recognized in an asset acquisition; any excess consideration transferred over the fair value of the net assets acquired is allocated to the non-monetary identifiable assets and liabilities assumed based on relative fair values. Acquired in-process research and development ("IPR&D") is expensed as incurred provided there is no alternative future use.

Goodwill and other Indefinite Lived Intangible Assets

Indefinite-lived intangible assets consist of goodwill and IPR&D acquired in a business combination.

Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. Goodwill is not amortized but is tested for impairment at least annually or more frequently if events or changes in circumstances indicate that the asset may be impaired. The Company’s impairment tests are based on a single operating segment and reporting unit structure. If the carrying value of the reporting unit exceeds its fair value, an impairment charge is recognized for the excess of the carrying value of the reporting unit over its fair value.

IPR&D assets represent the fair value of incomplete research and development projects that had not reached technological feasibility as of the date of acquisition; initially, these are classified as IPR&D and are not subject to amortization. Once these research and development projects are completed, the asset balances are transferred from IPR&D to acquisition-related developed technology and are subject to amortization from this point forward. The Company reviews IPR&D for possible impairment annually or more frequently if events or changes in circumstances indicate that carrying amount may not be recoverable. Significant assumptions inherent in the evaluation and measurement of impairment include, but are not limited to, external factors such as industry and economic trends, and internal factors such as changes in the Company’s business strategy and the Company’s forecasts for specific projects.

Deferred Offering Costs

Costs directly related to the Company’s IPO are deferred for expense recognition and instead capitalized and recorded within other long-term assets on the accompanying consolidated balance sheets. These costs consist of legal fees, accounting fees, and other applicable professional services. These deferred offering costs have been reclassified to additional paid in capital upon the closing of the IPO. There were no deferred offering costs capitalized as of December 31, 2021, as the IPO occurred in March 2021. As part of the IPO there were underwriting discounts and commissions of $25.8 million and other offering expenses of $3.2 million. As of December 31, 2020, $0.5 million of deferred offering costs were capitalized.

Revenue

Revenue recognized during the year ended December 31, 2020 is primarily related to the Company’s commercial services agreement with a customer to provide storage and processing of clinical material harvested from patients related to the compassionate use program. The Company receives fixed fees per patient and procedure. Revenue related to this services agreement is recognized once services are performed as there is no alternative use for the asset once the activities is performed and the Company has the right to consideration in an amount that corresponds directly with the value provided to its customer and its performance completed to date. The commercial service agreement ended during 2020, therefore there was no revenue recognized during the year ended December 31, 2021.

Grant Proceeds

The Company receives government grants in the U.K. for the furtherance of certain research and development projects. Grant proceeds are recognized when all conditions of such grants are fulfilled or there is a reasonable assurance that they will be fulfilled. Grant proceeds are classified as a reduction of research and development expenses. For the years ended December 31, 2021 and 2020, $1.7 million and $1.2 million, of grant proceeds were recognized in research and development expenses on the Company’s consolidated statements of operations and comprehensive loss, respectively.

Research and Development Expenses

Research and development (“R&D”) costs are expensed as incurred. Advance payments for research and development activities are deferred as prepaid expenses, classified as current or noncurrent on the Company’s consolidated balance sheets based on the estimated timing the related services will be performed and are expensed as the related services are performed. Costs incurred by third parties pursuant to contracts with research institutions and clinical research organizations are expensed as the contracted work is performed. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or project and the invoices received from the external service providers. The Company adjusts its accrual as actual costs become known. If the actual timing of the performance of services or the level of effort varies significantly from the estimate, the Company will adjust the accrual accordingly. The Company has not experienced any material differences between accrued costs and actual costs incurred since its inception.

Research and development expenses are presented net of government grants, as described above, and R&D tax and expenditure credits from the U.K. government, which are recognized over the period necessary to match the reimbursement with the related costs when it is probable that the Company has complied with any conditions attached and will receive the reimbursement. Reimbursable R&D tax and expenditure credits were $1.8 million and $0.2 million in the years ended December 31, 2021 and 2020, respectively.

Stock-Based Compensation

The Company measures its stock-based awards granted to employees, non-employee directors, consultants and independent advisors based on the estimated grant date fair value of the awards. For stock-based awards with only service conditions, compensation expense is recognized over the requisite service period using the straight-line method. For stock-based awards that include performance conditions, compensation expense is not recognized until the performance condition is probable to occur. The Company uses the Black-Scholes option pricing model to estimate the fair value of its stock-based awards. The Black-Scholes option pricing model requires the Company to make assumptions and judgements about the variables used in the calculations, including the fair value of common stock, expected term, expected volatility of the Company’s common stock, risk-free interest rate and expected dividend yield. The Company accounts for forfeitures of stock-based awards as they occur.

Income Taxes

Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts or existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period of enactment. The Company records a valuation allowance to reduce deferred tax assets to an amount expected to be realized.

The Company recognizes the tax benefit from an uncertain tax position if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the merits of the position. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component

of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.

Foreign Currency

The Company’s reporting currency is the U.S. dollar. The functional currency of the Company’s subsidiary located in the United Kingdom is the British Sterling. Balance sheets prepared in the functional currency are translated to the reporting currency at exchange rates in effect at the end of the accounting period, except for stockholders’ deficit accounts, which are translated at rates in effect when these balances were originally recorded. Revenue and expense accounts are translated using an average exchange rate in effect during the period. The resulting foreign currency translation adjustments are recorded as a separate component of accumulated other comprehensive loss in the accompanying consolidated balance sheets.

Gains and losses resulting from exchange rate changes on intercompany transactions denominated in a currency other than the local currency are included in earnings as incurred as the related amounts are expected to be repaid in the foreseeable future.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of the Company’s common stock outstanding for the period, without consideration for potential dilutive shares of common stock. For purposes of the diluted net loss per share calculation, convertible preferred stock and common stock options are considered to be potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented since the effects of potentially dilutive securities are antidilutive given the net loss of the Company.

Comprehensive Loss

Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. For the year ended December 31, 2021, comprehensive loss consists of foreign currency translation adjustments, and unrealized loss on available-for-sale securities net of tax. For the year ended December 31, 2020, comprehensive loss consists of foreign currency translation adjustments.

Emerging Growth Company Status

The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to avail itself of this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Recent Accounting Pronouncements Not Yet Adopted

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) which supersedes FASB ASC Topic 840, Leases (Topic 840) and provides principles for the recognition, measurement, presentation, and disclosure of leases for both lessees and lessors. The new standard requires the lessees to classify leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee, and such classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than twelve months regardless of classification.

Leases with a term of twelve months or less will be accounted for similar to existing guidance for operating leases. In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates, which revised the effective date for ASU No. 2016-02, Leases (Topic 842) for fiscal years beginning after December 15, 2020. In June 2020, the FASB issued ASU No. 2020-05, Revenue From Contracts With Customers (Topic 606) and Leases (Topic 842): Effective Dates for Certain Entities, further delaying the effective date for ASU No. 2016-02, Leases (Topic 842) to fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company immediately adopted ASU No. 2019-10 and ASU No. 2020-05 upon issuance by the FASB.

The new standard is effective for the Company on January 1, 2022. The Company will adopt the new standard effective January 1, 2022 using the modified retrospective transition approach. The Company has completed a substantial portion of its evaluation of the effect of adopting ASC 842 on its financial statements. Upon adoption on January 1, 2022, the Company expects to recognize estimated right-of-use assets and lease liabilities totaling approximately $15 million and $9 million, respectively, to reflect the present value of remaining lease payments under existing lease arrangements. The difference between the leased assets and lease liabilities represents the existing deferred rent liabilities balance, resulting from historical straight-lining of operating leases, which will be effectively reclassified upon adoption to reduce the measurement of the leased assets. The Company will apply the modified retrospective transition approach and will not recast prior periods. Although the Company is applying this approach, it does not expect to record a cumulative effect adjustment to the opening balance of retained earnings upon adoption. As permitted by the standard, the Company will elect the transition practical expedient package, which among other things, allows the carryforward of historical lease classifications. Accordingly, the Company will continue to apply Topic 840 prior to January 1, 2022, including Topic 840 disclosure requirements, in the comparative periods presented.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. Additionally, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, in April 2019 and ASU 2019-05, Financial Instruments — Credit Losses (Topic 326) — Targeted Transition Relief, in May 2019. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. In November 2019, the FASB issued ASU No. 2019-10, which defers the effective date of ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The standard will be effective for the Company on January 1, 2022. The Company anticipates the adoption of the standard will not have a material impact on its consolidated financial statements.

In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The standard simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also improves consistent application by clarifying and amending existing guidance. The standard is effective for fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company anticipates the adoption of the standard will not have a material impact on its consolidated financial statements.

Balance Sheet Components

12 Months Ended

Dec. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

Property, Plant and Equipment, Net

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


	December 31,
	2021		2020
Land	$	31,243	$	31,243
Laboratory equipment	13,962		6,590
Buildings(1)	6,034		6,309
Office and computer equipment	2,239		1,510
Leasehold improvements	1,836		1,312
Manufacturing equipment	1,717		2,355
Vehicles	64		—
Construction work-in-progress	67,883		6,328
Total property, plant and equipment, gross	124,978		55,647
Less: accumulated depreciation	(2,979)		(306)
Total property, plant and equipment, net	$	121,999	$	55,341

______________________________________________________________

(1) Relates to buildings acquired as described below which are being developed as part of the Company’s clinical manufacturing facility in Tarzana, California. The buildings will be placed into service and depreciation will commence once the construction is complete and they are ready for intended use.

For the years ended December 31, 2021 and 2020 the Company recognized depreciation expense of $2.7 million and $0.3 million, respectively, in the consolidated statements of operations and comprehensive loss.

In October 2020, the Company acquired land and buildings in Tarzana, California, for $37.6 million. The Company is in the process of developing this land for its U.S. operations and has capitalized $67.0 million in work-in-progress costs associated with this development project. The Company’s contractual commitments for this development project are limited to unreimbursed spend by the general contractor and as such, as of December 31, 2021 and 2020, $63.2 million and $6.3 million, respectively, is contractually committed to the development of this project. This acquisition is classified as an asset acquisition for which the Company records identifiable assets acquired at cost on a relative fair value basis. The most significant component of the allocation of fair value was to the Company's land and buildings.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	December 31,
	2021		2020
Accrued construction costs	$	12,085	$	302
Accrued compensation and benefits	11,928		3,983
Accrued operational expenses	5,292		1,589
Accrued research and development expenses	4,234		1,616
Current tax liabilities	524		631
Other current liabilities	386		281
Total accrued expenses and other current liabilities	$	34,449	$	8,402

Transactions with Immetacyte

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

Transactions with Immetacyte

License Agreement with Immetacyte

In February 2019, the Company entered into an Exclusive License & Research Services Agreement (the “License Agreement”) with Immetacyte, whose key founders are also shareholders of the Company, pursuant to which the Company obtained a worldwide license to Immetacyte’s proprietary technology, know-how and intellectual property for the research, development and manufacture of TIL therapies obtained from tumors using Immetacyte’s technology.

The payments made for the license of the TIL technology were accounted for as IPR&D as part of an asset acquisition and were expensed as it was determined that there was no alternative future use for the license. The Company accounts for contingent consideration payable upon achievement of certain development or commercial milestones when the underlying contingency is resolved. For the year ended December 31, 2020, the Company recognized $0.6 million of IPR&D, which consisted of $0.3 million paid up front for the license and $0.3 million paid for achievement of a development milestone, which was recognized as a component of research and development expense in the Company’s statement of operations and comprehensive loss.

Additionally, the Company was obligated to make payments for the research and development, manufacturing, monitoring and general services which included: (i) research and development services payments of $1.9 million annually for each of the first three years, (ii) manufacturing services payments of $1.2 million for the first annual period and $1.6 million for two years thereafter, and (iii) $0.3 million for monitoring and general services.

Upon the acquisition of Immetacyte, the License Agreement was terminated.

Acquisition of Immetacyte

In March 2020, the Company acquired 100% of the share capital of Immetacyte for $0.8 million in cash consideration, 5.6 million shares of common stock at an estimated fair value of $0.58 per share and up to an aggregate of $14.8 million of cash contingent consideration. The contingent consideration was additional cash consideration payable to the seller up until January 31, 2040 upon achievement of distinct product development milestones. The Company believes the acquisition, which includes the dedicated workforce of Immetacyte, will better position itself in developing an innovative cell therapy pipeline of autologous TIL therapies for the treatment of patients with cancer.

The fair value of consideration paid was as follows (in thousands):


Cash consideration	$	779
Common stock of 5,640,000 shares at an estimated fair value of $0.58 per share	3,243
Contingent consideration	11,349
Total consideration	$	15,371

The allocation of the purchase consideration was based on management’s estimate of the acquisition date fair values of the assets acquired and liabilities assumed, as follows (in thousands):


Assets acquired:
Net working capital	$	870
Property, plant and equipment	690
Intangibles	10,104
Total assets acquired	11,664
Goodwill	5,722
Deferred tax liabilities	(2,015)
Total purchase price	$	15,371

The acquisition was accounted for as a business combination and, accordingly, the total fair value of purchase consideration was allocated to the tangible and intangible assets acquired and liabilities assumed based on their fair values on the acquisition date. Due to the Company’s pre-commercialization stage, many of the processes and methods used in the production of TILs were still in experimental development and pre-clinical stages and as such, resulted in a $10.1 million IPR&D asset. To value the IPR&D, the Company utilized the multi-period excess earnings method under the income approach. The method reflects the present value of the operating cash flows generated by this asset after taking into account the cost to realize the revenue, and an appropriate discount rate to reflect the time value and risk associated with the invested capital. These assumptions were applied to a relief-from-royalty model.

Within net working capital, was $0.8 million of acquired gross trade receivables, all of which has been collected. Goodwill is attributable to the assembled workforce and expected synergies from combining operations.

The goodwill recognized for this acquisition is not deductible for income tax purposes. From the acquisition date through December 31, 2021, there has been no change in the carrying amount of goodwill. Because the acquired IPR&D has an indefinite life, it is not amortized but rather evaluated for impairment. As of December 31, 2021 and 2020, IPR&D was not impaired.

The Company recognized acquisition-related costs of $0.9 million for the year ended December 31, 2020, which were expensed as incurred within general and administrative on the consolidated statements of operations and comprehensive loss.

Fair Value Measurement

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurement

The fair value of cash and cash equivalents approximates carrying value since cash and cash equivalents consist of short-term highly liquid investments with maturities of less than three months at the time of purchase. Cash and cash equivalents are quoted market prices in active markets for identical assets and are therefore classified as Level 1 assets. Money market funds are open-end mutual funds that invest in cash, government securities, and/or repurchase agreements that are collateralized fully. To the extent that these funds are valued based upon the reported net asset value, they are categorized in Level 1 of the fair value hierarchy.

Short-term marketable securities comprised of U.S. Treasury bills that are classified within Level 2 of the fair value hierarchy are valued based on other observable inputs, including broker or dealer quotations, alternative pricing sources or U.S. Government Treasury yield of appropriate term.

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis:


	As of December 31, 2021
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	18,493	$	—	$	—	$	18,493
U.S. Treasury bills	—		416,509		—		416,509
Total	$	18,493	$	416,509	$	—	$	435,002
Financial Liabilities
Contingent consideration	$	—	—		12,321		$	12,321

	As of December 31, 2020
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	106,138	—		—		$	106,138
Financial Liabilities
Contingent consideration	$	—	—		12,277		$	12,277

There were no transfers in and out of Level 1, 2 and 3 measurements for the years ended December 31, 2021 and 2020. As of December 31, 2021 and 2020, there were no securities within Level 3 of the fair value hierarchy. The following table sets forth a summary of the changes in the fair value of the Company's Level 3 financial liabilities (in thousands):


	Year Ended December 31, 2021
Fair value, beginning balance	$	12,277
Change in fair value	294
Development milestone achieved	(250)
Fair value, ending balance	$	12,321


	Year Ended December 31, 2020
Fair value, beginning balance	$	—
Contingent consideration recorded as a result of Immetacyte acquisition	11,349
Change in present value of contingent consideration	928
Fair value, ending balance	$	12,277

The Company’s acquisition of Immetacyte involved the potential for the payment of future contingent consideration upon the achievement of (i) certain product development milestones including, approval of studies and commencement and completion of certain product trials, or (ii) various other performance conditions including, receipt of final approval for the first marketing authorization and first commercial sale in certain geographical markets. Contingent consideration is recorded at the estimated fair value of the contingent payments on the acquisition date. The fair value of the contingent consideration is remeasured at the estimated fair value at each reporting period with the change in fair value recognized as income or expense within research and development expense in the consolidated statements of operations and comprehensive loss.

The Company determines the fair value of the contingent consideration by probability weighting scenarios of milestone achievements to determine the expected future contingent consideration payment, discounted to present value using an 8.5% discount rate based on the Company’s pre-tax cost of debt on the acquisition date. The probability of payments ranged from 20% to 100% and the timing of future payments ranged from 2020 to 2026. In determining the likelihood of milestone achievements which trigger payouts related to the contingent consideration, the probabilities for various scenarios, as well as the discount rate used in the Company’s calculations were based on internal unobservable projections. During the year ended December 31, 2020, no contingent consideration payments were made by the Company. As a result, as of December 31, 2020, the estimated future payments included the payment previously expected to be made in late 2020. As of December 31, 2020, the probability and timing of payments ranged from 20% to 100% and 2021 to 2026, respectively. As of December 31, 2020, the discount rate used in discounting the expected contingent consideration payments changed to 8% based on the Company’s pre-tax cost of debt, which increased the fair value of the contingent consideration by $0.9 million from the acquisition date.

During the year ended December 31, 2021, the change of fair value related to the contingent consideration is due to the change in present value for the passage of time, as well as expected dates and probabilities of milestone achievement revisions. During the year ended December 31, 2021, the Company recognized a development milestone achievement, which is classified as an accrued expense in other current liabilities in the consolidated balance sheet as of December 31, 2021.

- 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

Financial Instruments

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Financial Instruments

Marketable securities classified as available-for-sale at December 31, 2021 consisted of the following (in thousands):


	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	416,559	$	—	$	(50)	$	416,509

As of December 31, 2021, all marketable securities had original contractual maturities less than one year. There were no marketable securities classified as available-for-sale at December 31, 2020.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Operating Leases

The Company leases various operating spaces in the U.S. and U.K. under non-cancelable operating lease arrangements that expire on various dates through the end of 2026. These arrangements require the Company to pay certain operating expenses, such as service charges, taxes, repairs, and insurance and contain landlord or tenant incentives or allowances, and renewal escalation clauses. The Company recognizes rent expense under these arrangements on a straight-line basis over the term of the lease and records the difference between the rent paid and recognition of rent expense as a deferred rent liability. Total rent expense was $3.0 million and $0.5 million for the years ended December 31, 2021 and 2020, respectively.

Future minimum lease payments under noncancellable operating leases as of December 31, 2021 were as follows (in thousands):


2022	$	2,411
2023	2,354
2024	2,215
2025	1,936
2026 and thereafter	1,272
Total	$	10,188

Construction Commitments

The Company’s contractual commitments for the development of the Tarzana project are limited to unreimbursed spend by the general contractor and as such, as of December 31, 2021, was $63.2 million, which is contractually committed to the development of this project.

Legal Proceedings

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company does not expect that the resolution of these matters will have a material adverse effect on its financial position, results of operations or cash flows.

Indemnifications

The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance coverage that reduces its exposure and enables the Company to recover a portion of any future amounts paid. No liability associated with such indemnifications was recorded as of December 31, 2021 and 2020.

Commitments and Contingencies

Operating Leases

Future minimum lease payments under noncancellable operating leases as of December 31, 2021 were as follows (in thousands):


2022	$	2,411
2023	2,354
2024	2,215
2025	1,936
2026 and thereafter	1,272
Total	$	10,188

Construction Commitments

Legal Proceedings

Indemnifications

Equity

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Equity

Common Stock

Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and if declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the board of directors from inception.

In March 2020, the Company issued 5.6 million shares of its common stock at an estimated fair value of $0.58 per share to purchase Immetacyte (see Note 4).

In November 2020, the Company executed a limited recourse promissory note with its Chief Executive Officer (“CEO”), Bronson Crouch, in the amount of $1.1 million which was secured by a pledge of a total of 3.2 million shares of its common stock issued upon exercise of vested stock options. The note bore an interest rate of 2.5% per annum with a maturity date of the earlier of (i) five years from the date of the note or (ii) one business day prior to

the filing or submission of the Company’s first registration statement covering the Company’s common stock with the SEC. The principal and interest under the note may be repaid at any time without penalty. Because the Company only has partial recourse under the promissory note, the Company deemed the note receivable to be non-substantive. As such, the note receivable was not reflected in the consolidated financial statements and the related stock transaction will be recorded at the time the note receivable is settled in cash. As of December 31, 2020, the outstanding balance of the promissory note was $1.1 million. The promissory note was fully repaid in January 2021.

On March 23, 2021, the Company completed its IPO through an underwritten sale of an aggregate of an aggregate of 18,400,000 shares of its common stock at a price of $20.00 per share (see Note 2).

As of December 31, 2021, the Company had outstanding 129,028,278 shares of common stock.

Convertible Preferred Stock

As of December 31, 2020, there were 70,176,046 shares of preferred stock outstanding and the Company issued 4,174,551 shares of the Company Series C convertible preferred stock subsequent to December 31, 2020. Concurrent with the IPO, all then-outstanding shares of the Company's convertible preferred stock outstanding were automatically converted into an aggregate of 89,220,699 shares of common stock and were reclassified into permanent equity. Following the IPO, there are no shares of preferred stock outstanding.

Convertible preferred stock consisted of the following (in thousands, except shares):


	As of December 31, 2020
	Shares Authorized	Shares Issued and Outstanding	Aggregate Liquidation Preference
Series A	25,000,000	25,000,000	$	25,000
Series B	34,600,523	34,600,523	170,200
Series C	14,750,075	10,575,523	133,000
	74,350,598	70,176,046	$	328,200

All outstanding shares of convertible preferred stock were converted on a 1.2-for-1 conversion ratio of shares of common stock on March 23, 2021, the date of closing of the Company's IPO (see Note 2).

The Company classified the convertible preferred stock outside of total stockholders’ deficit because, in the event of certain deemed liquidation events that are not solely within the control of the Company, the shares would become redeemable at the option of the holders. The Company did not adjust the carrying values of the convertible preferred stock to the deemed liquidation values of such shares since a liquidation event was not probable of occurring at December 31, 2020. Subsequent adjustments to increase or decrease the carrying values to the ultimate liquidation values will be made only if, and when, it becomes probable that such a liquidation event will occur.

As of December 31, 2020, the holders of the Company’s convertible preferred stock had various rights, preferences and privileges as follows:

Voting Rights

The holders of convertible preferred stock were entitled to cast the number of votes equal to the number of shares of common stock into which the shares of convertible preferred stock held by such holder were convertible as of the record date at any shareholder meeting of the Company. Except as provided by law or by the other provisions of the Company’s amended and restated certificate of incorporation, holders of convertible preferred stock and

common stock were entitled to vote together as a single class. Holders of Series A convertible preferred stock, exclusively and as a separate class, were entitled to elect one member of the Company’s board of directors and holders of Series B convertible preferred stock, exclusively and as a separate class, were entitled to elect three members to the Company’s board of directors.

Dividends

Holders of convertible preferred stock were entitled to receive noncumulative cash dividends in an amount equal to 8% of their respective original (pre-split) issue price of $1.00, $4.92 and $12.58 for Series A, Series B and Series C convertible preferred stock, respectively, per annum per share (subject to appropriate adjustment in the event of any stock dividends, stock splits, stock combinations, recapitalizations or similar events), when and if declared by the Company’s board of directors, prior and in preference to the holders of common stock. As of December 31, 2021, no dividends had been declared.

Liquidation

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or deemed liquidation event, the holders of shares of Series C convertible preferred stock were entitled to receive, prior and in preference to any distribution to the holders of Series B convertible preferred stock, an amount equal to the greater of (i) $12.58 per share, plus any dividends declared but unpaid or (ii) such amount per share as would have been payable in respect of each share of Series C convertible preferred stock had all shares of Series C convertible preferred stock been converted into common stock immediately prior to such liquidation, dissolution, winding up or deemed liquidation event. After the required payment to Series C convertible stockholders, holders of shares of Series B convertible preferred stock were entitled to receive, prior and in preference to any distribution to the holders of Series A convertible preferred stock, an amount equal to the greater of (i) $4.92 per share, plus any dividends declared but unpaid or (ii) such amount per share as would have been payable in respect of each share of Series B convertible preferred stock had all shares of Series B convertible preferred stock been converted into common stock immediately prior to such liquidation, dissolution, winding up or deemed liquidation event. After the required payment to Series B convertible stock holders, holders of shares of Series A convertible preferred stock were entitled to receive, prior and in preference to any distribution to the holders of common stock, an amount equal to the greater of (i) $1.00 per share, plus any dividends declared but unpaid or (ii) such amount per share as would have been payable in respect of each share of Series A convertible preferred stock had all shares of Series A convertible preferred stock been converted into common stock immediately prior to such liquidation, dissolution, winding up or deemed liquidation event. After the required payment is made to the preferred stockholders, the remaining assets of the Company, if any, were to be distributed to the holders of common stock pro rata based on the number of shares held by each such holder.

Optional Conversion Rights

Each share of convertible preferred stock was convertible, at the option of the holder, into such number of shares of common stock as was determined by dividing the original issue price for that series by the conversion price for such series in effect at the time of conversion. The conversion price was $0.83, $4.10 and $10.48 per share with respect to the shares of Series A, Series B and Series C convertible preferred stock, respectively, and was subject to certain anti-dilution adjustments.

Mandatory Conversion

Each share of convertible preferred stock was to be automatically converted into shares of common stock at the then effective conversion ratio for such share upon the earlier of (i) the closing of the sale of shares of common stock to the public at a price of at least $12.58 per share (subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization) with the gross cash proceeds to the Company of at least $100 million, or (ii) the date and time, or the occurrence of an event, specified by vote or written consent of the holders of at least a majority of outstanding shares of (a) Series B convertible preferred stock, (b) Series C

convertible preferred stock not also holding Series B convertible preferred stock, and (c) all convertible preferred stock.

2021 Preferred Stock Activity

All currently outstanding shares of convertible preferred stock were converted into an aggregate of 89,220,699 shares of common stock on March 23, 2021, the closing date of the Company's IPO (see Note 2). After the completion of the IPO, the Company's current amended and restated certificate of incorporation authorizes the Company to issue up to 10,000,000 shares of preferred stock at $0.000001 par value per share. The board of directors are authorized to provide for the issue of the shares of the preferred stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in subsequent resolution or resolutions adopted by the board providing for the issuance of such shares. As of December 31, 2021, there have been no shares of preferred stock issued and outstanding by the Company.

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
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+ Details

Stock-Based Compensation

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation

2021 Equity Incentive Plan

In March 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective in connection with the IPO. The 2021 Plan was approved by the Company’s board of directors and stockholders in March 2021. The 2021 Plan is an equity incentive plan pursuant to which the Company may grant the following awards: (i) incentive stock options; (ii) nonstatutory stock options; (iii) stock appreciation rights; (iv) restricted stock awards; (v) restricted stock unit awards; (vi) performance awards; and (vii) other forms of stock awards to employees, directors, and consultants, including employees and consultants of the Company’s affiliates. The 2021 Plan is a successor to the Company's 2018 Stock Incentive Plan (the “2018 Plan”). Following the effectiveness of the 2021 Plan, no further grants may be made under the 2018 Plan; however, any outstanding equity awards granted under the 2018 Plan will continue to be governed by the terms of the 2018 Plan.

The number of shares available for future issuance under the 2021 Plan is the sum of (1) 8,660,000 new shares of common stock, (2) 4,194,437 remaining shares of common stock reserved under the 2018 Plan that became available for issuance upon the effectiveness of the 2021 Plan and (3) the number of shares of common stock subject to outstanding awards under the 2018 Plan when the 2021 Plan became effective that thereafter expire or are forfeited, canceled, withheld to satisfy tax withholding or to purchase or exercise an award, repurchased by the Company or are otherwise terminated. The number of shares of common stock reserved for issuance under the 2021 Plan will automatically increase on January 1 of each year, for a period of ten years, from January 1, 2022 continuing through January 1, 2031, by 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Company’s board of directors. Stock options granted by the Company to employees generally vest over four years with a one-year cliff.

As of December 31, 2021, 9,854,288 shares of common stock remained available for issuance under the 2021 Plan. As of December 31, 2021, the total number of shares authorized for issuance under the 2021 Plan was 12,854,437 shares.

The following summarizes option activity under the 2021 Plan:


	Shares Available for Grant	Shares Issuable Under Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contract Term (in years)	Aggregate Intrinsic Value (in thousands)
Balance, December 31, 2019	3,892,000	6,508,000	$	0.35	9.68	$	1,106
Additional Shares Authorized	15,740,977
Options granted(1)	(10,741,522)	10,741,522	$	1.05
Options forfeited	1,325,775	(1,325,775)	$	0.71
Options exercised(2)	—	(591,824)	$	0.62
Balance, December 31, 2020	10,217,230	15,331,923	$	0.80	9.22	$	78,857
Additional Shares Authorized	8,660,000
Options granted(1)	(9,413,187)	9,413,187	$	9.96
Options forfeited	390,245	(390,245)	$	5.28
Options exercised	—	(3,976,028)	$	0.44
Balance, December 31, 2021	9,854,288	20,378,837	$	5.17	8.75	$	247,880
Exercisable, December 31, 2021		5,563,411	$	1.94	8.32	$	84,622
Vested and expected to vest, December 31, 2021		5,563,411	$	1.94	8.32	$	84,622

______________________________________________________________

(1) Includes 2,519,137 and 1,101,600 stock options during the years ended December 31, 2021 and 2020, respectively, subject to only performance conditions.

(2) Excludes the exercise of 3,159,750 stock options that are subject to a limited recourse promissory note.

The aggregate intrinsic value disclosed in the above table is based on the difference between the exercise price of the stock option and the estimated fair value of the Company’s common stock as of the respective period-end dates. There were 3,976,028 and 591,824 stock options exercised during the years ended December 31, 2021 and 2020, respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2021 and 2020, was $66.3 million and $1.5 million, respectively. The weighted-average grant date fair value of stock options granted during the years ended December 31, 2021 and 2020, was $11.59 and $0.68 per share, respectively.

The following table sets forth stock-based compensation included in the Company’s statement of operations and comprehensive loss (in thousands):


	Year Ended December 31,
	2021		2020
Research and development expense	$	12,912	$	418
General and administrative expense	13,285		1,288
Total stock-based compensation expense	$	26,197	$	1,706

As of December 31, 2021 and 2020, there was $69.5 million and $6.1 million of total unrecognized compensation cost related to unvested stock options granted under the 2018 Plan and 2021 Plan (excluding performance awards), which is expected to be recognized over a weighted average period of 2.24 years and 3.26 years, respectively.

The fair value of the Company’s stock option awards was estimated at the date of grant using a Black-Scholes option pricing model with the following assumptions:


	Year Ended December 31,
	2021				2020
Expected term (in years)	5.77		—	6.24	5.88		—	6.10
Expected volatility	72.52	%	—	89.11%	82.54	%	—	88.62%
Risk-free interest rate	0.51	%	—	1.44%	0.31	%	—	0.55%
Fair value of common stock	$5.95		—	$26.44	$0.58		—	$1.22
Expected dividend yield	—%				—%

Prior to the Company's IPO in March 2021, the fair value of the shares of common stock underlying stock options had historically been determined by the Company’s board of directors. Because there has been no public market for the Company’s common stock, the board of directors has determined fair value of the common stock at the time of grant of the option by considering a number of objective and subjective factors including important developments in the Company’s operations, contemporaneous valuations performed by an independent third party firm, sales of the Company’s convertible preferred stock, the Company’s operating results and financial performance, the conditions in the biotechnology industry and the economy in general, the stock price volatility of similar public companies and the lack of marketability of the Company’s common stock, among other factors. After the Company’s IPO in March 2021, the fair value of common stock is determined using the closing price of the Company’s common stock on the Nasdaq Global Select Market.

The Black-Scholes option pricing model requires the use of highly subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Expected term—The expected term represents the period that stock-based awards are expected to be outstanding and is determined as the average of the time-to-vesting and the contractual life of the awards.

Expected volatility—Since the Company is privately held and does not have any trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on their similar size, stage in the life cycle or area of specialty.

Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of awards.

Expected dividend yield—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

Performance Awards

During the years ended December 31, 2021 and 2020, 2,519,137 and 511,200 stock options vested to both employees and non-employees based upon performance conditions and strategic transactions. 2021 performance grants are expected to be recognized over a weighted average period of 2.92 years, and the 2020 performance grants have been vested. A strategic transaction has been defined as (a) a change in control, (b) the Company’s next capital raise or (c) an initial public offering of the Company’s shares, in which the Company receives at least $50.0 million in gross proceeds. Included in stock-based compensation expense for the year ended December 31, 2021 is $9.1 million related to awards where performance conditions were achieved. During the year ended December 31, 2020, the Company’s Series B financing met the definition of a strategic transaction, triggering the immediate vesting of the performance awards. The Company recognized $0.8 million in compensation expense relating to the performance awards as of the closing of the Series B convertible preferred stock financing. As of December 31, 2021 and 2020, the Company had $21.1 million and $0.2 million of unrecognized compensation cost relating to these performance awards, calculated using the accelerated attribution method and the grant date fair value of the awards, respectively.

Employee Stock Purchase Plan

In March 2021, the Company adopted the Employee Stock Purchase Plan (the “ESPP”), which became effective in connection with the IPO. The ESPP was adopted by the Company’s board of directors and stockholders in March 2021. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 1,237,000 shares of common stock. The number of shares of common stock reserved for issuance will automatically increase on January 1st of each calendar year for a period of up to ten years, commencing on January 1, 2022 and ending on (and including) January 1, 2031, in an amount equal to the lesser of (i) one percent (1%) of the total number of shares of capital stock outstanding on the last day of the calendar month before the date of the automatic increase, and (ii) 2,474,000 shares of common stock. Notwithstanding the foregoing, the board may act prior to the first day of any calendar year to provide that there will be no January 1st increase in the share reserve for such calendar year or that the increase in the share reserve for such calendar year will be a lesser number of shares of common stock than would otherwise occur pursuant to the preceding sentence.

Net Loss Per Share

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net Loss Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:


	December 31,
	2021	2020
Convertible preferred stock	—	70,176,046
Stock options to purchase common stock	20,378,837	9,012,423
Shares of common stock collateralizing note receivable from stockholder	—	3,159,750
Total	20,378,837	82,348,219

All outstanding shares of convertible preferred stock were converted on a 1.2-for-1 conversion ratio of shares of common stock on March 23, 2021, the date of the Company's IPO (see Note 2).

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

The geographical breakdown of loss before provision for income taxes is as follows (in thousands):


	Year Ended December 31,
	2021		2020
Domestic	$	(154,778)	$	(38,646)
Foreign	(1,977)		1,059
Loss before income taxes	$	(156,755)	$	(37,587)

The components of the provision for income taxes are as follows (in thousands):


	Year Ended December 31,
	2021		2020
Current provision for income taxes:
Foreign	$	—	$	(116)
Total current	—		(116)
Deferred tax provision:
Domestic	18		—
Foreign	21		267
Total deferred	39		267
Total income tax expense	$	39	$	151

The following table presents a reconciliation of the Company’s statutory federal income tax rate and effective tax rate:


	Year Ended December 31,
	2021		2020
U.S federal taxes at statutory rate	21.0	%	21.0	%
Research and development tax credits	0.9	%	2.6	%
Stock-based compensation	(3.1)	%	1.0	%
Permanent differences and other	(0.3)	%	(1.3)	%
Loss on issuance of Series A convertible preferred stock	0.0	%	(2.5)	%
Statutory tax rate differences	2.7	%	0.1	%
Change in valuation allowance	(21.2)	%	(21.3)	%
Total	0.0	%	(0.4)	%

The components of deferred tax liabilities consist of the following (in thousands):


	Year Ended December 31,
	2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	36,726	$	8,120
Research and development credits	4,682		848
Accrued compensation and benefits	2,364		728
Stock-based compensation	744		142
Other temporary differences	1,033		29
Total gross deferred tax assets	45,549		9,867
Less: valuation allowance	(42,737)		(9,522)
Total deferred tax assets, net	2,812		345
Deferred tax liabilities:
Intangible assets	(2,672)		(2,049)
Fixed assets	(2,566)		(641)
Other	—		(126)
Total gross deferred tax liabilities	(5,238)		(2,816)
Net deferred tax liabilities	$	(2,426)	$	(2,471)

The components of unrecognized tax benefits consist of the following (in thousands):


Balance at December 31, 2020:	$	—
Additions in 2021	2,339
Balance at December 31, 2021:	$	2,339

In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Due to the uncertainty of the business in which the Company operates, projections of future profitability are difficult and past profitability is not necessarily indicative of future profitability. The Company does not believe it is more likely than not that the deferred tax assets will be realized, and accordingly, the valuation allowance increased $33.2 million for the year ended December 31, 2021. As of December 31, 2021, the Company had net operating loss carryforwards for federal income tax purposes of $158.1 million, which will carryforward indefinitely, but may only offset 80% of the Company’s taxable income. This change may require the Company to pay federal income taxes in future years despite generating a loss for federal income tax purposes in prior years. In addition, the Company has $14.2 million of net operating loss carryforwards available to reduce future taxable income, for California state income tax purposes for the year ended December 31, 2021. The state net operating loss carryforwards will begin to expire, if not utilized, in 2041.The Company has R&D credits of $4.1 million, and $3.7 million for federal and California, respectively, as of December 31, 2021. The federal R&D credits expire in 2040 and the California R&D credits carryforward indefinitely.

On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, permits net operating loss carryforwards generated in taxable years beginning after December 31, 2017, to offset 100% of taxable income for taxable years beginning before January 1, 2021, and 80% of taxable income in taxable years beginning after

December 31, 2020. The CARES Act does not have a material impact on the Company’s financial results for the year ended December 31, 2020.

The Company files income tax returns in the U.S. federal jurisdiction, various states where the Company has employees and/or significant business activities, and the U.K. As of December 31, 2021, the Company’s federal and state returns through 2020 are still open to examination. The U.K. returns starting from 2016 are open to examination. The Company did not have any uncertain tax positions as of December 31, 2020. The Company had $2.3 million of uncertain tax positions as of December 31, 2021. The Company does not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease during the next 12 months. The Company had no accrued interest or penalties related to uncertain tax positions as of December 31, 2021.

The Company has not completed a Section 382 study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since the Company’s formation. Pursuant to Internal Revenue Code Sections 382 and 383, annual use of the Company’s net operating loss and research and development tax credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. If eliminated, the related asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, will not impact the Company’s effective tax rate.

- 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
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries Instil Bio (UK) Ltd. (formerly Immetacyte Ltd. (“Immetacyte”)) and Complex Therapeutics, LLC. Immetacyte was acquired on March 2, 2020 and Complex Therapeutics, LLC was incorporated on October 14, 2020. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include but are not limited to the fair value of stock valuations prior to the Company's initial public offering, the fair value of acquired intangible assets, the fair value of contingent consideration payable, and the fair value of buildings and land in an asset acquisition. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates.
Concentration of Credit Risk	Concentration of Credit Risk Financial Instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and marketable securities. The Company's cash and cash equivalents are held by two financial institutions in the United States ("U.S.") and one financial institution in the United Kingdom ("U.K."), which management believes to be financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions. At times, the Company's deposits held in the U.S. and U.K. may exceed the Federal Depository Insurance Corporation and Financial Services Compensation Scheme, respectively, insured limits.
Risks and Uncertainties	Risks and UncertaintiesThe Company is subject to a number of risks similar to other development-stage biopharmaceutical companies, including but not limited to, dependency on the clinical and commercial success of its product candidates, ability to obtain regulatory approval of its product candidates, uncertainty of broad adoption of its approved products, if any, by physicians and patients, manufacturing, the need to obtain adequate additional funding, significant competition, and protection of its intellectual property portfolio.
COVID-19 Pandemic	COVID-19 Pandemic On March 11, 2020, the World Health Organization characterized the outbreak of COVID-19 as a global pandemic and recommended containment and mitigation measures. Since then, extraordinary actions have been taken by international, federal, state, and local public health and governmental authorities to contain and combat the outbreak and spread of COVID-19 in regions throughout the world. These actions include travel bans, quarantines, “stay-at-home” orders and similar mandates for many individuals to substantially restrict daily activities and for many businesses to curtail or cease normal operations. As a result of COVID-19, the Company has taken precautionary measures in order to minimize the risk of the virus to its employees and the communities in which it operates. There has been minimal disruption in the Company’s ability to ensure the effective operation of its business. While the broader implications of the COVID-19 pandemic on the Company’s results of operations and overall financial performance remain uncertain, including any implications from the spread of the new Delta and Omicron variants of COVID-19, the COVID-19 pandemic has, to date, not had a material adverse impact on its results of operations or our ability to raise funds to sustain operations. The economic effects of the pandemic and resulting societal changes are currently not predictable, and the future financial impacts could vary from those foreseen.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents, Restricted Cash and Marketable Securities The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents include amounts invested in money market accounts. Restricted cash consists of a money market account which serves as collateral for the Company’s employee corporate credit cards and is classified within other long-term assets on the consolidated balance sheets.
Marketable Securities	Our short-term marketable securities have original maturities of less than a year at date of purchase. We classify and account for our marketable securities as available-for-sale securities, which are carried at their fair values based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred. As of December 31, 2021, marketable securities consisted of U.S. Treasury bills. The Company had no holdings of marketable securities as of December 31, 2020.Short-term marketable securities are recorded at their estimated fair value. We periodically review whether our securities may be other-than-temporarily impaired, including whether or not (i) we have the intent to sell the security or (ii) it is more likely than not that we will be required to sell the security before its anticipated recovery. If one of these factors is met, we will record an impairment loss associated with our impaired investment. The impairment loss will be recorded as a write-down of investments in the consolidated balance sheets and a realized loss within other expense in the consolidated statements of operations. For the year ended December 31, 2021, there were no impairment losses for the investments.
Fair Value Measurement	Fair Value Measurement Assets and liabilities recorded at fair value on a recurring basis in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value maximize the use of observable inputs and minimize the use of unobservable inputs. The Company measures fair value based on a three-tier hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 —Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2 —Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the assets or liabilities. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In determining fair value, the Company utilize quoted market prices, or valuation techniques that maximize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value.
Property, Plant and Equipment, Net	Property, Plant and Equipment, Net Property, plant and equipment, with the exception of land, is stated at cost less accumulated depreciation. Depreciation is computed on a straight-line basis over the estimated useful lives of the related assets. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations and comprehensive loss. The estimated useful lives of the Company’s property, plant and equipment are as follows: Laboratory equipment 7 years Manufacturing equipment 7 years Office and computer equipment 3 years Leasehold improvements Shorter of remaining lease term or estimated useful life The Company owns land and buildings that it is in the process of developing for its U.S. operations. As described in Note 3, the buildings are still in development and depreciation will commence once the clinical manufacturing facility is ready for its intended use. A variety of costs are incurred in the development of a property. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when the development project is substantially complete and placed into service to begin depreciation involves a degree of judgment. The costs of land and buildings under development include specifically identifiable costs. The capitalized costs include pre-construction costs essential to the development of the property, development costs, and construction costs. When the development project is substantially complete and available for occupancy, the Company ceases capitalization of costs other than costs to improve the functionality or extend the useful lives of property, plant and equipment included as part of the project.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or that the useful life is shorter than originally estimated. Recoverability of assets is measured by comparing the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset over its remaining useful life. If such assets are impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. If the useful life is shorter than originally estimated, the Company depreciates or amortizes the remaining carrying value over the revised shorter useful life. Assets to be disposed of by sale are reflected at the lower of their carrying amount or fair value less cost to sell.
Business Combinations	Business Combinations The Company evaluates acquisitions of assets and related liabilities and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs which would meet the requirements of a business. The Company accounts for its business combinations using the acquisition method of accounting which requires recognition and measurement of all identifiable assets acquired and liabilities assumed at their full fair value as of the date it obtains control. The Company has determined the fair value of assets acquired and liabilities assumed based upon management's estimates of the fair values of assets acquired and liabilities assumed in the acquisitions. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable assets acquired. The Company accounts for contingent considerations at the acquisition-date fair value as part of the consideration transferred in the transactions. While management has used its best estimates and assumptions to measure the fair value of the identifiable assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, not to exceed one year from the date of acquisition, any changes in the estimated fair values of the net assets recorded for the acquisition will result in an adjustment to goodwill. Upon the conclusion of the measurement period of final determination of the values of assets acquired or liabilities assumed, whichever comes first, the Company records any subsequent adjustments to the consolidated statements of operations and comprehensive loss. Acquisition-related costs, such as legal and consulting fees, are expensed as incurred. The Company accounts for an asset acquisition by recognizing net assets based on the cost to the acquiring entity on a relative fair value basis, which includes transaction costs in addition to consideration given. Goodwill is not recognized in an asset acquisition; any excess consideration transferred over the fair value of the net assets acquired is allocated to the non-monetary identifiable assets and liabilities assumed based on relative fair values. Acquired in-process research and development ("IPR&D") is expensed as incurred provided there is no alternative future use.
Goodwill and other Indefinite Lived Intangible Assets	Goodwill and other Indefinite Lived Intangible Assets Indefinite-lived intangible assets consist of goodwill and IPR&D acquired in a business combination. Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. Goodwill is not amortized but is tested for impairment at least annually or more frequently if events or changes in circumstances indicate that the asset may be impaired. The Company’s impairment tests are based on a single operating segment and reporting unit structure. If the carrying value of the reporting unit exceeds its fair value, an impairment charge is recognized for the excess of the carrying value of the reporting unit over its fair value. IPR&D assets represent the fair value of incomplete research and development projects that had not reached technological feasibility as of the date of acquisition; initially, these are classified as IPR&D and are not subject to amortization. Once these research and development projects are completed, the asset balances are transferred from IPR&D to acquisition-related developed technology and are subject to amortization from this point forward. The Company reviews IPR&D for possible impairment annually or more frequently if events or changes in circumstances indicate that carrying amount may not be recoverable. Significant assumptions inherent in the evaluation and measurement of impairment include, but are not limited to, external factors such as industry and economic trends, and internal factors such as changes in the Company’s business strategy and the Company’s forecasts for specific projects.
Deferred Offering Costs	Deferred Offering CostsCosts directly related to the Company’s IPO are deferred for expense recognition and instead capitalized and recorded within other long-term assets on the accompanying consolidated balance sheets. These costs consist of legal fees, accounting fees, and other applicable professional services. These deferred offering costs have been reclassified to additional paid in capital upon the closing of the IPO.
Revenue	Revenue Revenue recognized during the year ended December 31, 2020 is primarily related to the Company’s commercial services agreement with a customer to provide storage and processing of clinical material harvested from patients related to the compassionate use program. The Company receives fixed fees per patient and procedure. Revenue related to this services agreement is recognized once services are performed as there is no alternative use for the asset once the activities is performed and the Company has the right to consideration in an amount that corresponds directly with the value provided to its customer and its performance completed to date. The commercial service agreement ended during 2020, therefore there was no revenue recognized during the year ended December 31, 2021.
Grant Proceeds	Grant ProceedsThe Company receives government grants in the U.K. for the furtherance of certain research and development projects. Grant proceeds are recognized when all conditions of such grants are fulfilled or there is a reasonable assurance that they will be fulfilled. Grant proceeds are classified as a reduction of research and development expenses
Research and Development Expenses	Research and Development Expenses Research and development (“R&D”) costs are expensed as incurred. Advance payments for research and development activities are deferred as prepaid expenses, classified as current or noncurrent on the Company’s consolidated balance sheets based on the estimated timing the related services will be performed and are expensed as the related services are performed. Costs incurred by third parties pursuant to contracts with research institutions and clinical research organizations are expensed as the contracted work is performed. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or project and the invoices received from the external service providers. The Company adjusts its accrual as actual costs become known. If the actual timing of the performance of services or the level of effort varies significantly from the estimate, the Company will adjust the accrual accordingly. The Company has not experienced any material differences between accrued costs and actual costs incurred since its inception. Research and development expenses are presented net of government grants, as described above, and R&D tax and expenditure credits from the U.K. government, which are recognized over the period necessary to match the reimbursement with the related costs when it is probable that the Company has complied with any conditions attached and will receive the reimbursement.
Stock-Based Compensation	Stock-Based Compensation The Company measures its stock-based awards granted to employees, non-employee directors, consultants and independent advisors based on the estimated grant date fair value of the awards. For stock-based awards with only service conditions, compensation expense is recognized over the requisite service period using the straight-line method. For stock-based awards that include performance conditions, compensation expense is not recognized until the performance condition is probable to occur. The Company uses the Black-Scholes option pricing model to estimate the fair value of its stock-based awards. The Black-Scholes option pricing model requires the Company to make assumptions and judgements about the variables used in the calculations, including the fair value of common stock, expected term, expected volatility of the Company’s common stock, risk-free interest rate and expected dividend yield. The Company accounts for forfeitures of stock-based awards as they occur.
Income Taxes	Income Taxes Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts or existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period of enactment. The Company records a valuation allowance to reduce deferred tax assets to an amount expected to be realized. The Company recognizes the tax benefit from an uncertain tax position if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the merits of the position. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.
Foreign Currency	Foreign Currency The Company’s reporting currency is the U.S. dollar. The functional currency of the Company’s subsidiary located in the United Kingdom is the British Sterling. Balance sheets prepared in the functional currency are translated to the reporting currency at exchange rates in effect at the end of the accounting period, except for stockholders’ deficit accounts, which are translated at rates in effect when these balances were originally recorded. Revenue and expense accounts are translated using an average exchange rate in effect during the period. The resulting foreign currency translation adjustments are recorded as a separate component of accumulated other comprehensive loss in the accompanying consolidated balance sheets. Gains and losses resulting from exchange rate changes on intercompany transactions denominated in a currency other than the local currency are included in earnings as incurred as the related amounts are expected to be repaid in the foreseeable future.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of the Company’s common stock outstanding for the period, without consideration for potential dilutive shares of common stock. For purposes of the diluted net loss per share calculation, convertible preferred stock and common stock options are considered to be potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented since the effects of potentially dilutive securities are antidilutive given the net loss of the Company.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. For the year ended December 31, 2021, comprehensive loss consists of foreign currency translation adjustments, and unrealized loss on available-for-sale securities net of tax. For the year ended December 31, 2020, comprehensive loss consists of foreign currency translation adjustments.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) which supersedes FASB ASC Topic 840, Leases (Topic 840) and provides principles for the recognition, measurement, presentation, and disclosure of leases for both lessees and lessors. The new standard requires the lessees to classify leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee, and such classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than twelve months regardless of classification. Leases with a term of twelve months or less will be accounted for similar to existing guidance for operating leases. In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates, which revised the effective date for ASU No. 2016-02, Leases (Topic 842) for fiscal years beginning after December 15, 2020. In June 2020, the FASB issued ASU No. 2020-05, Revenue From Contracts With Customers (Topic 606) and Leases (Topic 842): Effective Dates for Certain Entities, further delaying the effective date for ASU No. 2016-02, Leases (Topic 842) to fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company immediately adopted ASU No. 2019-10 and ASU No. 2020-05 upon issuance by the FASB. The new standard is effective for the Company on January 1, 2022. The Company will adopt the new standard effective January 1, 2022 using the modified retrospective transition approach. The Company has completed a substantial portion of its evaluation of the effect of adopting ASC 842 on its financial statements. Upon adoption on January 1, 2022, the Company expects to recognize estimated right-of-use assets and lease liabilities totaling approximately $15 million and $9 million, respectively, to reflect the present value of remaining lease payments under existing lease arrangements. The difference between the leased assets and lease liabilities represents the existing deferred rent liabilities balance, resulting from historical straight-lining of operating leases, which will be effectively reclassified upon adoption to reduce the measurement of the leased assets. The Company will apply the modified retrospective transition approach and will not recast prior periods. Although the Company is applying this approach, it does not expect to record a cumulative effect adjustment to the opening balance of retained earnings upon adoption. As permitted by the standard, the Company will elect the transition practical expedient package, which among other things, allows the carryforward of historical lease classifications. Accordingly, the Company will continue to apply Topic 840 prior to January 1, 2022, including Topic 840 disclosure requirements, in the comparative periods presented. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. Additionally, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, in April 2019 and ASU 2019-05, Financial Instruments — Credit Losses (Topic 326) — Targeted Transition Relief, in May 2019. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. In November 2019, the FASB issued ASU No. 2019-10, which defers the effective date of ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The standard will be effective for the Company on January 1, 2022. The Company anticipates the adoption of the standard will not have a material impact on its consolidated financial statements. In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The standard simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also improves consistent application by clarifying and amending existing guidance. The standard is effective for fiscal years beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2022. The Company anticipates the adoption of the standard will not have a material impact on its consolidated financial statements.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of Cash, Cash Equivalents and Restricted Cash


	December 31,
	2021		2020
Cash and cash equivalents	$	37,590	$	241,714
Restricted cash	500		50
Cash, cash equivalents and restricted cash	$	38,090	$	241,764

Schedule of Cash, Cash Equivalents and Restricted Cash


	December 31,
	2021		2020
Cash and cash equivalents	$	37,590	$	241,714
Restricted cash	500		50
Cash, cash equivalents and restricted cash	$	38,090	$	241,764

Schedule of Useful Lives

The estimated useful lives of the Company’s property, plant and equipment are as follows:

Laboratory equipment 7 years

Manufacturing equipment 7 years

Office and computer equipment 3 years

Leasehold improvements Shorter of remaining lease term or estimated useful life

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


	December 31,
	2021		2020
Land	$	31,243	$	31,243
Laboratory equipment	13,962		6,590
Buildings(1)	6,034		6,309
Office and computer equipment	2,239		1,510
Leasehold improvements	1,836		1,312
Manufacturing equipment	1,717		2,355
Vehicles	64		—
Construction work-in-progress	67,883		6,328
Total property, plant and equipment, gross	124,978		55,647
Less: accumulated depreciation	(2,979)		(306)
Total property, plant and equipment, net	$	121,999	$	55,341

______________________________________________________________

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Property, Plant and Equipment, Net

The estimated useful lives of the Company’s property, plant and equipment are as follows:

Laboratory equipment 7 years

Manufacturing equipment 7 years

Office and computer equipment 3 years

Leasehold improvements Shorter of remaining lease term or estimated useful life

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


	December 31,
	2021		2020
Land	$	31,243	$	31,243
Laboratory equipment	13,962		6,590
Buildings(1)	6,034		6,309
Office and computer equipment	2,239		1,510
Leasehold improvements	1,836		1,312
Manufacturing equipment	1,717		2,355
Vehicles	64		—
Construction work-in-progress	67,883		6,328
Total property, plant and equipment, gross	124,978		55,647
Less: accumulated depreciation	(2,979)		(306)
Total property, plant and equipment, net	$	121,999	$	55,341

______________________________________________________________

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	December 31,
	2021		2020
Accrued construction costs	$	12,085	$	302
Accrued compensation and benefits	11,928		3,983
Accrued operational expenses	5,292		1,589
Accrued research and development expenses	4,234		1,616
Current tax liabilities	524		631
Other current liabilities	386		281
Total accrued expenses and other current liabilities	$	34,449	$	8,402

Transactions with Immetacyte (Tables)

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

Schedule of Acquisition

The fair value of consideration paid was as follows (in thousands):


Cash consideration	$	779
Common stock of 5,640,000 shares at an estimated fair value of $0.58 per share	3,243
Contingent consideration	11,349
Total consideration	$	15,371

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

The allocation of the purchase consideration was based on management’s estimate of the acquisition date fair values of the assets acquired and liabilities assumed, as follows (in thousands):


Assets acquired:
Net working capital	$	870
Property, plant and equipment	690
Intangibles	10,104
Total assets acquired	11,664
Goodwill	5,722
Deferred tax liabilities	(2,015)
Total purchase price	$	15,371

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis:


	As of December 31, 2021
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	18,493	$	—	$	—	$	18,493
U.S. Treasury bills	—		416,509		—		416,509
Total	$	18,493	$	416,509	$	—	$	435,002
Financial Liabilities
Contingent consideration	$	—	—		12,321		$	12,321

	As of December 31, 2020
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	106,138	—		—		$	106,138
Financial Liabilities
Contingent consideration	$	—	—		12,277		$	12,277

Reconciliation of Level 3 Financial Liabilities

The following table sets forth a summary of the changes in the fair value of the Company's Level 3 financial liabilities (in thousands):


	Year Ended December 31, 2021
Fair value, beginning balance	$	12,277
Change in fair value	294
Development milestone achieved	(250)
Fair value, ending balance	$	12,321


	Year Ended December 31, 2020
Fair value, beginning balance	$	—
Contingent consideration recorded as a result of Immetacyte acquisition	11,349
Change in present value of contingent consideration	928
Fair value, ending balance	$	12,277

Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities

Marketable securities classified as available-for-sale at December 31, 2021 consisted of the following (in thousands):


	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	416,559	$	—	$	(50)	$	416,509

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments

Future minimum lease payments under noncancellable operating leases as of December 31, 2021 were as follows (in thousands):


2022	$	2,411
2023	2,354
2024	2,215
2025	1,936
2026 and thereafter	1,272
Total	$	10,188

Equity (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Schedule of Convertible Preferred Stock

Convertible preferred stock consisted of the following (in thousands, except shares):


	As of December 31, 2020
	Shares Authorized	Shares Issued and Outstanding	Aggregate Liquidation Preference
Series A	25,000,000	25,000,000	$	25,000
Series B	34,600,523	34,600,523	170,200
Series C	14,750,075	10,575,523	133,000
	74,350,598	70,176,046	$	328,200

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Option Activity

The following summarizes option activity under the 2021 Plan:


	Shares Available for Grant	Shares Issuable Under Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contract Term (in years)	Aggregate Intrinsic Value (in thousands)
Balance, December 31, 2019	3,892,000	6,508,000	$	0.35	9.68	$	1,106
Additional Shares Authorized	15,740,977
Options granted(1)	(10,741,522)	10,741,522	$	1.05
Options forfeited	1,325,775	(1,325,775)	$	0.71
Options exercised(2)	—	(591,824)	$	0.62
Balance, December 31, 2020	10,217,230	15,331,923	$	0.80	9.22	$	78,857
Additional Shares Authorized	8,660,000
Options granted(1)	(9,413,187)	9,413,187	$	9.96
Options forfeited	390,245	(390,245)	$	5.28
Options exercised	—	(3,976,028)	$	0.44
Balance, December 31, 2021	9,854,288	20,378,837	$	5.17	8.75	$	247,880
Exercisable, December 31, 2021		5,563,411	$	1.94	8.32	$	84,622
Vested and expected to vest, December 31, 2021		5,563,411	$	1.94	8.32	$	84,622

______________________________________________________________

(1) Includes 2,519,137 and 1,101,600 stock options during the years ended December 31, 2021 and 2020, respectively, subject to only performance conditions.

(2) Excludes the exercise of 3,159,750 stock options that are subject to a limited recourse promissory note.

Schedule of Stock-Based Compensation Expense

The following table sets forth stock-based compensation included in the Company’s statement of operations and comprehensive loss (in thousands):


	Year Ended December 31,
	2021		2020
Research and development expense	$	12,912	$	418
General and administrative expense	13,285		1,288
Total stock-based compensation expense	$	26,197	$	1,706

Schedule of Valuation Assumptions

The fair value of the Company’s stock option awards was estimated at the date of grant using a Black-Scholes option pricing model with the following assumptions:


	Year Ended December 31,
	2021				2020
Expected term (in years)	5.77		—	6.24	5.88		—	6.10
Expected volatility	72.52	%	—	89.11%	82.54	%	—	88.62%
Risk-free interest rate	0.51	%	—	1.44%	0.31	%	—	0.55%
Fair value of common stock	$5.95		—	$26.44	$0.58		—	$1.22
Expected dividend yield	—%				—%

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:


	December 31,
	2021	2020
Convertible preferred stock	—	70,176,046
Stock options to purchase common stock	20,378,837	9,012,423
Shares of common stock collateralizing note receivable from stockholder	—	3,159,750
Total	20,378,837	82,348,219

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Geographical Breakdown of Loss before Provision for Income Taxes

The geographical breakdown of loss before provision for income taxes is as follows (in thousands):


	Year Ended December 31,
	2021		2020
Domestic	$	(154,778)	$	(38,646)
Foreign	(1,977)		1,059
Loss before income taxes	$	(156,755)	$	(37,587)

Schedule of Components of the Provision for Income Taxes

The components of the provision for income taxes are as follows (in thousands):


	Year Ended December 31,
	2021		2020
Current provision for income taxes:
Foreign	$	—	$	(116)
Total current	—		(116)
Deferred tax provision:
Domestic	18		—
Foreign	21		267
Total deferred	39		267
Total income tax expense	$	39	$	151

Schedule of Effective Income Tax Rate Reconciliation

The following table presents a reconciliation of the Company’s statutory federal income tax rate and effective tax rate:


	Year Ended December 31,
	2021		2020
U.S federal taxes at statutory rate	21.0	%	21.0	%
Research and development tax credits	0.9	%	2.6	%
Stock-based compensation	(3.1)	%	1.0	%
Permanent differences and other	(0.3)	%	(1.3)	%
Loss on issuance of Series A convertible preferred stock	0.0	%	(2.5)	%
Statutory tax rate differences	2.7	%	0.1	%
Change in valuation allowance	(21.2)	%	(21.3)	%
Total	0.0	%	(0.4)	%

Schedule of Deferred Tax Assets and Liabilities

The components of deferred tax liabilities consist of the following (in thousands):


	Year Ended December 31,
	2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	36,726	$	8,120
Research and development credits	4,682		848
Accrued compensation and benefits	2,364		728
Stock-based compensation	744		142
Other temporary differences	1,033		29
Total gross deferred tax assets	45,549		9,867
Less: valuation allowance	(42,737)		(9,522)
Total deferred tax assets, net	2,812		345
Deferred tax liabilities:
Intangible assets	(2,672)		(2,049)
Fixed assets	(2,566)		(641)
Other	—		(126)
Total gross deferred tax liabilities	(5,238)		(2,816)
Net deferred tax liabilities	$	(2,426)	$	(2,471)

Schedule of Unrecognized Tax Benefits Roll Forward

The components of unrecognized tax benefits consist of the following (in thousands):


Balance at December 31, 2020:	$	—
Additions in 2021	2,339
Balance at December 31, 2021:	$	2,339

Summary of Significant Accounting Policies - Narrative (Details)			12 Months Ended
	Mar. 23, 2021 USD ($) shares	Mar. 12, 2021	Dec. 31, 2021 USD ($) segment shares	Dec. 31, 2020 USD ($) shares	Mar. 24, 2021 shares	Dec. 31, 2019 shares
Subsidiary, Sale of Stock [Line Items]
Stock split (in shares)		1.2
Net proceeds from sale of stock	$ 339,000,000
Underwriting discounts and commissions	25,800,000
Other offering expenses	$ 3,200,000
Shares issued upon conversion (in shares) \| shares	89,220,699
Common stock, shares authorized (in shares) \| shares			300,000,000	111,000,000	300,000,000
Convertible preferred stock, shares authorized (in shares) \| shares			10,000,000	74,350,598	10,000,000
Convertible preferred stock outstanding (in shares) \| shares			0	70,176,046	0	15,000,000
Number of segments \| segment			1
Deferred offering costs			$ 0	$ 500,000
Grant proceeds			1,700,000	1,200,000
Reimbursable research and development tax and expenditure credits			$ 1,800,000	$ 200,000
Accounting standards update, extensible enumeration			us-gaap:AccountingStandardsUpdate201602Member
Pro Forma \| Cumulative Effect, Period of Adoption, Adjustment
Subsidiary, Sale of Stock [Line Items]
Operating lease right-of-use assets			$ 15,000,000
Operating lease liabilities			$ 9,000,000
Underwriter purchase option
Subsidiary, Sale of Stock [Line Items]
Shares sold (in shares) \| shares	2,400,000

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 37,590	$ 241,714
Restricted cash	500	50
Cash, cash equivalents and restricted cash	$ 38,090	$ 241,764	$ 8,895

Summary of Significant Accounting Policies - Useful Life (Details)	12 Months Ended
	Dec. 31, 2021
Laboratory equipment
Property, Plant and Equipment [Line Items]
Useful life	7 years
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Useful life	7 years
Office and computer equipment
Property, Plant and Equipment [Line Items]
Useful life	3 years

Balance Sheet Components - Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 124,978	$ 55,647
Less: accumulated depreciation	(2,979)	(306)
Total property, plant and equipment, net	121,999	55,341
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	31,243	31,243
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	13,962	6,590
Building
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	6,034	6,309
Office and computer equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	2,239	1,510
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	1,836	1,312
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	1,717	2,355
Vehicles
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	64	0
Construction work-in-progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 67,883	$ 6,328

Balance Sheet Components - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Depreciation expense		$ 2,700	$ 300
Payments to acquire buildings	$ 37,600	57,831	50,816
Work in progress		67,000
Contractual commitment		$ 63,200	$ 6,300

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued construction costs	$ 12,085	$ 302
Accrued compensation and benefits	11,928	3,983
Accrued operational expenses	5,292	1,589
Accrued research and development expenses	4,234	1,616
Current tax liabilities	524	631
Other current liabilities	386	281
Total accrued expenses and other current liabilities	$ 34,449	$ 8,402

Transactions with Immetacyte - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2020	Feb. 28, 2019
Business Acquisition [Line Items]
In-process research and development		$ 600
Upfront fee		300
Development milestone payment		300
Annual research and development services to be paid next three years			$ 1,900
Manufacturing services to be paid, first annual period			1,200
Annual manufacturing services to be paid next two years			1,600
Monitoring and general services to be paid			$ 300
Immetacyte
Business Acquisition [Line Items]
Percentage of share capital acquired	100.00%
Cash consideration	$ 779
Shares issued (in shares)	5,640,000
Shares issued, price per share (in dollars per share)	$ 0.58
Contingent consideration, maximum	$ 14,800
Intangibles	10,104
Gross trade receivables acquired	$ 800
Acquisition costs expensed		$ 900

Transactions with Immetacyte - Fair Value of Consideration (Details) - Immetacyte $ / shares in Units, $ in Thousands	1 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Business Acquisition [Line Items]
Cash consideration	$ 779
Common stock of 5,640,000 shares at an estimated fair value of $0.58 per share	3,243
Contingent consideration	11,349
Total consideration	$ 15,371
Shares issued (in shares) \| shares	5,640,000
Shares issued, price per share (in dollars per share) \| $ / shares	$ 0.58

Transactions with Immetacyte - Allocation of Purchase Consideration (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 5,722	$ 5,722
Immetacyte
Business Acquisition [Line Items]
Net working capital			$ 870
Property, plant and equipment			690
Intangibles			10,104
Total assets acquired			11,664
Goodwill			5,722
Deferred tax liabilities			(2,015)
Total purchase price			$ 15,371

Fair Value Measurement - Financial Assets and Liabilities (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Financial Assets
U.S. Treasury bills		$ 0
U.S. Treasury bills
Financial Assets
U.S. Treasury bills	$ 416,509,000
Fair Value, Recurring
Financial Assets
Total	435,002,000
Financial Liabilities
Contingent consideration	12,321,000	12,277,000
Fair Value, Recurring \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	416,509,000
Fair Value, Recurring \| Level 1
Financial Assets
Total	18,493,000
Financial Liabilities
Contingent consideration	0	0
Fair Value, Recurring \| Level 1 \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	0
Fair Value, Recurring \| Level 2
Financial Assets
Total	416,509,000
Financial Liabilities
Contingent consideration	0	0
Fair Value, Recurring \| Level 2 \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	416,509,000
Fair Value, Recurring \| Level 3
Financial Assets
Total	0
Financial Liabilities
Contingent consideration	12,321,000	12,277,000
Fair Value, Recurring \| Level 3 \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	0
Money market funds \| Fair Value, Recurring
Financial Assets
Money market funds	18,493,000	106,138,000
Money market funds \| Fair Value, Recurring \| Level 1
Financial Assets
Money market funds	18,493,000	106,138,000
Money market funds \| Fair Value, Recurring \| Level 2
Financial Assets
Money market funds	0	0
Money market funds \| Fair Value, Recurring \| Level 3
Financial Assets
Money market funds	$ 0	$ 0

Fair Value Measurement - Level 3 Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 12,277	$ 0
Contingent consideration recorded as a result of Immetacyte acquisition		11,349
Development milestone achieved	(250)
Change in fair value	294	928
Fair value, ending balance	$ 12,321	$ 12,277

Fair Value Measurement - Narrative (Details)	12 Months Ended
Fair Value Measurement - Narrative (Details)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration payments		$ 0
Increase in fair value of contingent consideration	$ 294,000	$ 928,000
Measurement Input, Discount Rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Measurement input		0.085
Measurement Input, Discount Rate \| Change In Pre-Tax cost Of Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Measurement input		0.08
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Payment probability		20.00%
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Payment probability		100.00%

Financial Instruments - Summary of Investments (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fair Value		$ 0
U.S. Treasury bills
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 416,559,000
Unrealized Gains	0
Unrealized Losses	(50,000)
Fair Value	$ 416,509,000

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 3.0	$ 0.5
Contractual commitment	$ 63.2	$ 6.3

Commitments and Contingencies - Future Minimum Payments (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2022	$ 2,411
2023	2,354
2024	2,215
2025	1,936
2026 and thereafter	1,272
Total	$ 10,188

Equity - Narrative (Details)		1 Months Ended		12 Months Ended
Equity - Narrative (Details)	Mar. 23, 2021 $ / shares shares	Nov. 30, 2020 USD ($) shares	Mar. 31, 2020 $ / shares shares	Dec. 31, 2021 USD ($) vote $ / shares shares	Dec. 31, 2020 USD ($) board_member $ / shares shares	Mar. 24, 2021 $ / shares shares	Dec. 31, 2019 shares
Class of Stock [Line Items]
Common stock, votes per share \| vote				1
Promissory note \| $		$ 1,100,000			$ 1,100,000
Promissory note secured by pledge, number of shares (in shares)		3,200,000
Interest rate		2.50%
Promissory note, term		5 years
Promissory note, days prior to filing of first registration statement		1 day
Common stock, shares outstanding (in shares)				129,028,278	20,591,554
Convertible preferred stock outstanding (in shares)				0	70,176,046	0	15,000,000
Issuance of convertible preferred shares (in shares)				4,174,551
Shares issued upon conversion (in shares)	89,220,699
Conversion ratio	1.2
Dividend rate					8.00%
Dividends declared \| $				$ 0
Mandatory conversion, common stock share price (at least) (in dollars per share) \| $ / shares					$ 12.58
Mandatory conversion, gross proceeds (at least) \| $					$ 100,000,000
Convertible preferred stock, shares authorized (in shares)				10,000,000	74,350,598	10,000,000
Convertible preferred stock, par value (in dollars per share) \| $ / shares				$ 0.000001	$ 0.000001	$ 0.000001
Convertible preferred stock issued (in shares)				0	70,176,046
IPO
Class of Stock [Line Items]
Shares sold (in shares)	18,400,000
Price per share sold (in dollars per share) \| $ / shares	$ 20.00
Immetacyte
Class of Stock [Line Items]
Shares issued (in shares)			5,640,000
Shares issued, price per share (in dollars per share) \| $ / shares			$ 0.58
Series A
Class of Stock [Line Items]
Convertible preferred stock outstanding (in shares)					25,000,000
Issuance of convertible preferred shares (in shares)					10,000,000
Number of board members entitled to elect \| board_member					1
Shares issued, price per share (in dollars per share) \| $ / shares					$ 1.00
Liquidation preference per share (in dollars per share) \| $ / shares					1.00
Conversion price (in dollars per share) \| $ / shares					$ 0.83
Convertible preferred stock, shares authorized (in shares)					25,000,000
Convertible preferred stock issued (in shares)					25,000,000
Series B
Class of Stock [Line Items]
Convertible preferred stock outstanding (in shares)					34,600,523
Issuance of convertible preferred shares (in shares)					34,600,523
Number of board members entitled to elect \| board_member					3
Shares issued, price per share (in dollars per share) \| $ / shares					$ 4.92
Liquidation preference per share (in dollars per share) \| $ / shares					4.92
Conversion price (in dollars per share) \| $ / shares					$ 4.10
Convertible preferred stock, shares authorized (in shares)					34,600,523
Convertible preferred stock issued (in shares)					34,600,523
Series C
Class of Stock [Line Items]
Convertible preferred stock outstanding (in shares)					10,575,523
Issuance of convertible preferred shares (in shares)					10,575,523
Shares issued, price per share (in dollars per share) \| $ / shares				$ 12.58	$ 12.58
Liquidation preference per share (in dollars per share) \| $ / shares					12.58
Conversion price (in dollars per share) \| $ / shares					$ 10.48
Convertible preferred stock, shares authorized (in shares)					14,750,075
Convertible preferred stock issued (in shares)					10,575,523

Equity - Preferred Stock (Details) - USD ($)	Dec. 31, 2021	Mar. 24, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)	10,000,000	10,000,000	74,350,598
Convertible preferred stock issued (in shares)	0		70,176,046
Convertible preferred stock outstanding (in shares)	0	0	70,176,046	15,000,000
Convertible preferred stock, liquidation preference	$ 0		$ 328,200,000
Series A
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)			25,000,000
Convertible preferred stock issued (in shares)			25,000,000
Convertible preferred stock outstanding (in shares)			25,000,000
Convertible preferred stock, liquidation preference			$ 25,000,000
Series B
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)			34,600,523
Convertible preferred stock issued (in shares)			34,600,523
Convertible preferred stock outstanding (in shares)			34,600,523
Convertible preferred stock, liquidation preference			$ 170,200,000
Series C
Class of Stock [Line Items]
Convertible preferred stock, shares authorized (in shares)			14,750,075
Convertible preferred stock issued (in shares)			10,575,523
Convertible preferred stock outstanding (in shares)			10,575,523
Convertible preferred stock, liquidation preference			$ 133,000,000

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (in shares)	8,660,000	8,660,000	15,740,977
Shares available for future issuance (in shares)		9,854,288
Term to authorize additional shares		10 years
Percentage of outstanding capital stock		5.00%
Shares authorized (in shares)		12,854,437
Options exercised (in shares)		(3,976,028)	(591,824)
Aggregate intrinsic value of options exercised		$ 66,300	$ 1,500
Options granted, weighted-average grant date fair value (in dollars per share)		$ 11.59	$ 0.68
Unrecognized compensation cost		$ 69,500	$ 6,100
Unrecognized compensation cost, recognition period		2 years 2 months 26 days	3 years 3 months 3 days
Options vested (in shares)		2,519,137
Strategic transaction, initial public offering, gross proceeds		$ 50,000
Total stock-based compensation expense		$ 26,197	$ 1,706
Share-based Payment Arrangement, Tranche One \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Share-based Payment Arrangement, Tranche One \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
Stock options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield		0.00%	0.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 21,100	$ 200
Options vested (in shares)			511,200
Total stock-based compensation expense		$ 9,100	$ 800
Performance Shares \| Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		2 years 11 months 1 day
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term to authorize additional shares		10 years
Percentage of outstanding capital stock		1.00%
Shares authorized (in shares)	1,237,000
Minimum number of additional shares to be authorized (in shares)		2,474,000
2018 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)		4,194,437

Stock-Based Compensation - Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Shares Available for Grant
Beginning balance (in shares)		10,217,230	3,892,000
Additional Shares Authorized (in shares)	8,660,000	8,660,000	15,740,977
Options granted (in shares)		(9,413,187)	(10,741,522)
Options forfeited (in shares)		390,245	1,325,775
Ending balance (in shares)		9,854,288	10,217,230	3,892,000
Shares Issuable Under Options
Beginning balance (in shares)		15,331,923	6,508,000
Options granted (in shares)		9,413,187	10,741,522
Options forfeited (in shares)		(390,245)	(1,325,775)
Options exercised (in shares)		(3,976,028)	(591,824)
Ending balance (in shares)		20,378,837	15,331,923	6,508,000
Exercisable (in shares)		5,563,411
Vested and expected to vest (in shares)		5,563,411
Weighted- Average Exercise Price
Beginning balance (in dollars per share)		$ 0.80	$ 0.35
Options granted (in dollars per share)		9.96	1.05
Options forfeited (in dollars per share)		5.28	0.71
Options exercised (in dollars per share)		0.44	0.62
Ending balance (in dollars per share)		5.17	$ 0.80	$ 0.35
Exercisable, weighted-average exercise price (in dollars per share)		1.94
Vested and expected to vest, weighted-average exercise price (in dollars per share)		$ 1.94
Balance, weighted-average remaining contract term		8 years 9 months	9 years 2 months 19 days	9 years 8 months 4 days
Exercisable, weighted-average remaining contract term		8 years 3 months 25 days
Vested and expected to vest, weighted-average remaining contract term		8 years 3 months 25 days
Balance, aggregate intrinsic value		$ 247,880	$ 78,857	$ 1,106
Exercisable, aggregate intrinsic value		84,622
Vested and expected to vest, aggregate intrinsic value		$ 84,622
Performance Shares
Shares Available for Grant
Options granted (in shares)		(2,519,137)	(1,101,600)
Shares Issuable Under Options
Options granted (in shares)		2,519,137	1,101,600
Stock options subject to limited recourse promissory note
Shares Issuable Under Options
Options exercised (in shares)			(3,159,750)

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 26,197	$ 1,706
Research and development expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	12,912	418
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 13,285	$ 1,288

Stock-Based Compensation - Valuation Assumption (Details) - Stock option - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	72.52%	82.54%
Expected volatility, maximum	89.11%	88.62%
Risk-free interest rate, minimum	0.51%	0.31%
Risk-free interest rate, maximum	1.44%	0.55%
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 9 months 7 days	5 years 10 months 17 days
Fair Value of Common Stock (in dollars per share)	$ 5.95	$ 0.58
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 2 months 26 days	6 years 1 month 6 days
Fair Value of Common Stock (in dollars per share)	$ 26.44	$ 1.22

Net Loss Per Share (Details)		12 Months Ended
Net Loss Per Share (Details)	Mar. 23, 2021	Dec. 31, 2021 shares	Dec. 31, 2020 shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)		20,378,837	82,348,219
Conversion ratio	1.2
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)		0	70,176,046
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)		20,378,837	9,012,423
Shares of common stock collateralizing note receivable from stockholder
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)		0	3,159,750

Income Taxes - Loss before Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Domestic	$ (154,778)	$ (38,646)
Foreign	(1,977)	1,059
Loss before income tax expense	$ (156,755)	$ (37,587)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123384075&loc=d3e41242-110953

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 944
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-Section S99
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-Subparagraph (SX 210.7-04(8))
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
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Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

Income Taxes - Current and Deferred Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Current provision for income taxes:
Foreign	$ 0	$ (116)
Total current	0	(116)
Deferred tax provision:
Domestic	18	0
Foreign	21	267
Total deferred	39	267
Income tax expense	$ 39	$ 151

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
U.S federal taxes at statutory rate	21.00%	21.00%
Research and development tax credits	0.90%	2.60%
Stock-based compensation	(3.10%)	1.00%
Permanent differences and other	(0.30%)	(1.30%)
Loss on issuance of Series A convertible preferred stock	0.00%	(2.50%)
Statutory tax rate differences	2.70%	0.10%
Change in valuation allowance	(21.20%)	(21.30%)
Total	0.00%	(0.40%)

Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 36,726	$ 8,120
Research and development credits	4,682	848
Accrued compensation and benefits	2,364	728
Stock-based compensation	744	142
Other temporary differences	1,033	29
Total gross deferred tax assets	45,549	9,867
Less: valuation allowance	(42,737)	(9,522)
Total deferred tax assets, net	2,812	345
Deferred tax liabilities:
Intangible assets	(2,672)	(2,049)
Fixed assets	(2,566)	(641)
Other	0	(126)
Total gross deferred tax liabilities	(5,238)	(2,816)
Net deferred tax liabilities	$ (2,426)	$ (2,471)

Income Taxes - Unrecognized Tax Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at December 31, 2020:	$ 0
Additions in 2021	2,339
Balance at December 31, 2021	$ 2,339

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance	$ 33,200
Uncertain tax positions	2,339	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	158,100
Federal \| Research & Development credits
Operating Loss Carryforwards [Line Items]
Tax credits carryforward	4,100
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	14,200
State \| Research & Development credits
Operating Loss Carryforwards [Line Items]
Tax credits carryforward	$ 3,700