0000950170-23-008523 | 10-K | XBRL Viewer

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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2022	Mar. 13, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	001-39370
Entity Registrant Name	Nkarta, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4515206
Entity Address, Address Line One	6000 Shoreline Court
Entity Address, Address Line Two	Suite 102
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	925
Local Phone Number	407-1049
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	NKTX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,928,670
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001787400
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
ICFR Auditor Attestation Flag	false
Entity Public Float			$ 345.9
Auditor Name	Ernst & Young LLP
Auditor Location	California
Auditor Firm ID	42
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement for the 2023 Annual Meeting of Stockholders to be filed with the U.S. Securities and Exchange Commission pursuant to Regulation 14A within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference in Part III, Items 10-14 of this Annual Report on Form 10-K.

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 37,494	$ 60,816
Short-term investments, available-for-sale	314,649	177,272
Prepaid expenses and other current assets	8,545	7,692
Total current assets	360,688	245,780
Restricted cash	2,743	2,098
Property and equipment, net	61,908	12,856
Operating lease right-of-use assets	45,749	11,678
Other long-term assets	1,850	1,491
Total assets	472,938	273,903
Current liabilities:
Accounts payable	1,761	1,112
Operating lease liabilities, current portion	4,249	2,484
Accrued and other current liabilities	16,036	9,347
Total current liabilities	22,046	12,943
Operating lease liabilities, net of current portion	78,685	9,975
Other long-term liabilities		18
Total liabilities	100,731	22,936
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $0.0001 par value; 54,350,179 shares authorized at December 31, 2022; no shares issued and outstanding at December 31, 2022 and 2021
Common stock, $0.0001 par value; 100,000,000 shares authorized at December 31, 2022; 48,877,806 and 32,971,107 shares issued and outstanding at December 31, 2022 and 2021, respectively	5	3
Additional paid-in capital	690,814	455,210
Accumulated other comprehensive loss	(679)	(150)
Accumulated deficit	(317,933)	(204,096)
Total stockholders' equity	372,207	250,967
Total liabilities and stockholders' equity	$ 472,938	$ 273,903

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	54,350,179	54,350,179
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	48,877,806	32,971,107
Common stock, shares outstanding	48,877,806	32,971,107

Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating expenses:
Research and development	$ 90,897,000	$ 63,412,000
General and administrative	28,058,000	23,017,000
Total operating expenses	118,955,000	86,429,000
Loss from operations	(118,955,000)	(86,429,000)
Other income (expense), net:
Interest income	5,588,000	370,000
Other expense, net	(470,000)	(16,000)
Total other income (expense), net	5,118,000	354,000
Net loss	(113,837,000)	(86,075,000)
Comprehensive loss:
Net loss	(113,837,000)	(86,075,000)
Other comprehensive loss:
Unrealized loss on securities	(529,000)	(153,000)
Comprehensive loss	$ (114,366,000)	$ (86,228,000)
Net loss per share, basic	$ (2.61)	$ (2.62)
Earnings Per Share, Diluted	$ (2.61)	$ (2.62)
Weighted-average number of common shares used in net loss per share, basic	43,631,722	32,856,883
Weighted-average number of common shares used in net loss per share, diluted	43,631,722	32,856,883

Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Secondary Offering	At-the-market offering	Common Stock	Common Stock Secondary Offering	Common Stock At-the-market offering	Additional Paid-In Capital	Additional Paid-In Capital Secondary Offering	Additional Paid-In Capital At-the-market offering	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2020	$ 321,220			$ 3			$ 439,235			$ (118,021)	$ 3
Beginning Balance, Shares at Dec. 31, 2020				32,627,963
Vesting of shares of common stock subject to repurchase	35						35
Vesting of shares of common stock subject to repurchase, Shares				62,045
Issuance of common stock upon exercise of stock option	1,479						1,479
Issuance of common stock upon exercise of stock option , Shares				281,099
Share-based compensation expense	14,461						14,461
Unrealized loss on short-term investments	(153)										(153)
Net loss	(86,075)									(86,075)
Ending Balance at Dec. 31, 2021	250,967			$ 3			455,210			(204,096)	(150)
Ending Balance, Shares at Dec. 31, 2021				32,971,107
Issuance of common stock upon secondary offering, net of issuance costs		$ 215,334	$ 1,559		$ 2			$ 215,332	$ 1,559
Issuance of common stock upon secondary offering, net of issuance costs, Shares				113,213	15,333,334	113,213
Vesting of shares of common stock subject to repurchase	15						15
Vesting of shares of common stock subject to repurchase, Shares				15,278
Issuance of common stock upon exercise of stock option	1,397						1,397
Issuance of common stock upon exercise of stock option , Shares				383,120
Issuance of common stock upon employee stock purchase plan	445						445
Issuance of common stock upon employee stock purchase plan,share				61,754
Share-based compensation expense	16,856						16,856
Unrealized loss on short-term investments	(529)										(529)
Net loss	(113,837)									(113,837)
Ending Balance at Dec. 31, 2022	$ 372,207			$ 5			$ 690,814			$ (317,933)	$ (679)
Ending Balance, Shares at Dec. 31, 2022				48,877,806

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (113,837)	$ (86,075)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	16,856	14,461
Depreciation and amortization expense	2,637	1,756
Accretion of discount and amortization of premium on investments, net	(818)	3,237
Non-cash lease expense	3,935	367
Realized loss on investments	490
Others		(30)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,489)	(4,435)
Operating lease liabilities	32,469
Accounts payable and accrued and other liabilities	2,757	2,792
Net cash used in operating activities	(57,000)	(67,927)
Cash flows from investing activities:
Purchases of available-for-sale securities	(385,887)	(227,282)
Proceeds from maturities of available-for-sale securities	248,309	264,841
Purchase of property and equipment	(47,111)	(5,025)
Net cash provided by (used in) investing activities	(184,689)	32,534
Cash flows from financing activities:
Proceeds from secondary offering, net of issuance costs	215,611
Proceeds from ATM offering, net of issuance costs	1,559
Proceeds from ESPP purchases	445
Proceeds from stock option exercises	1,397	1,479
Payments of deferred offering costs		(277)
Net cash provided by financing activities	219,012	1,202
Net decrease in cash and cash equivalents	(22,677)	(34,191)
Cash, cash equivalents and restricted cash at beginning of year	62,914	97,105
Cash, cash equivalents and restricted cash at end of year	40,237	62,914
Reconciliation of cash, cash equivalents and restricted cash to the balance sheets:
Cash and cash equivalents	37,494	60,816
Restricted cash	2,743	2,098
Total cash, cash equivalents and restricted cash	40,237	62,914
Supplemental disclosures of non-cash investing and financing activities:
Acquisitions of property and equipment in accounts payable	$ 4,579	$ 238

Description of Business

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business

1. Description of Business

Description of the Business

Nkarta, Inc. ("Nkarta" or the "Company") was incorporated in the State of Delaware in July 2015. The Company is a biopharmaceutical company developing engineered natural killer ("NK") cells to treat cancer. The Company is focused on leveraging the natural potent power of NK cells to identify and kill abnormal cells and recruit adaptive immune effectors to generate responses that are specific and durable. Nkarta is combining its NK expansion platform technology with proprietary cell engineering technologies to generate an abundant supply of NK cells, engineer enhanced NK cell recognition of tumor targets, and improve persistence for sustained activity in the body for the treatment of cancer. Nkarta’s goal is to develop off-the-shelf NK cell therapy product candidates to improve outcomes for patients. The Company’s operations are based in South San Francisco, California, and it operates in one segment.

Liquidity and Management Plans

The accompanying financial statements have been prepared assuming that the Company will continue as a going concern. Since inception, the Company has devoted substantially all of its efforts to organizing and staffing, business planning, raising capital, conducting preclinical studies and initiating clinical studies, and has not realized substantial revenues from its planned principal operations. In addition, the Company has a limited operating history, has incurred operating losses since inception and expects that it will continue to incur net losses into the foreseeable future as it continues its research and development activities. As of December 31, 2022, the Company had an accumulated deficit of $317.9 million and cash, cash equivalents, restricted cash and short-term investments of $354.9 million.

Management plans to continue to incur substantial costs in order to conduct research and development activities and additional capital will be needed to undertake these activities. The Company intends to raise such capital through debt or equity financings or other arrangements to fund operations. Management believes that the Company’s current cash, cash equivalents, restricted cash and short-term investments will provide sufficient funds to enable the Company to meet its obligations for at least twelve months from the filing date of this report.

Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principle ("U.S. GAAP"). COVID-19 Pandemic The COVID-19 pandemic has caused disruptions in the global economy and has affected and may in the future affect the Company’s business and operations in the future. In response to the pandemic, the Coronavirus Aid, Relief and Economic Security Act (the "CARES Act") was signed into law on March 27, 2020. The CARES Act, among other things, includes tax provisions relating to refundable payroll tax credits, deferment of employer’s social security payments, net operating loss utilization and carryback periods, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. The CARES Act had no impact on the Company’s income tax provision for the year ended December 31, 2022. The Company continues to evaluate the impact of the CARES Act on its financial position, results of operations and cash flows. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to preclinical studies, fair value of assets and liabilities, share-based compensation and income taxes. Management bases its estimates on historical experience, knowledge of current events and actions it may undertake in the future that management believes to be reasonable under the circumstances. Actual results may differ from these estimates and assumptions. Concentration of Credit Risk Financial instruments, which potentially subject the Company to concentration of credit risk, consist primarily of cash, cash equivalents and short-term investments. The Company maintains cash, cash equivalents and short-term investments with various high credit quality and are invested through banks and other financial institutions in the United States. Such deposits may be in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company has not experienced any losses on deposits since inception. Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company displays comprehensive loss and its components as part of the statements of operations and comprehensive loss. Fair Value of Financial Instruments The accounting guidance defines fair value, establishes a consistent framework for measuring fair value, and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of prepaid expenses and other current assets, accounts payable, accrued liabilities and other current liabilities are reasonable estimates of their fair value due to the short-term nature of these accounts. Cash, Cash Equivalents, Short-term Investments and Restricted Cash Cash and Cash Equivalents The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash includes demand deposits held in readily available checking accounts at a federally insured financial institution. Cash equivalents consist of money market funds. Short-term Investments Short-term investments consist of commercial debt securities, commercial paper and Government securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified most of its available-for-sale investment securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value, and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. The cost of debt securities is adjusted for amortization of purchase premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income in the statements of operations and comprehensive loss. Realized gains and losses on sales of securities are determined using the specific identification method and recorded in other income (expense), net in the statement of operations and comprehensive loss. Restricted Cash The Company is required to maintain letters of credit related to its office and lab space lease and the additional facility in South San Francisco that the Company plans to use for corporate offices, laboratories and manufacturing. This cash is the collateral for those letters of credit and per the terms of the leases, must remain in place until one to two months after the termination of the leases. As the remaining terms of the leases as of December 31, 2022 is greater than one year, the related restricted cash has been classified as non-current. Property and Equipment, Net Property and equipment, which consist of leasehold improvements, furniture and fixtures, research equipment, computers and software and construction-in-progress are stated at cost less accumulated depreciation. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which ranges from three to five years. Leasehold improvements are amortized over the remaining life of the lease for leasehold improvements at the time the asset is placed into service. Impairment of Long-Lived Assets The carrying value of long-lived assets, including property and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the asset may not be recoverable. An impairment loss is recognized when the total of estimated future undiscounted cash flows, expected to result from the use of the asset and its eventual disposition, are less than its carrying amount. Impairment, if any, would be assessed using discounted cash flows or other appropriate measures of fair value. Through December 31, 2022, there has been no such impairment losses recorded by the Company. Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and other benefits of research and development personnel, including associated share-based compensation, costs related to research activities, preclinical studies, clinical trial, drug manufacturing and allocated overhead and facility-related expenses. The Company accounts for non-refundable advance payments for goods or services that will be used in future research and development activities as expenses when the goods have been received or when the service has been performed rather than when the payment is made. Clinical trial costs are a component of research and development expenses. The Company expenses costs for its clinical trial activities performed by third parties, including clinical research organizations and other service providers, as they are incurred, based upon estimates of the work completed over the life of the individual study in accordance with associated agreements. The Company uses information it receives from internal personnel and outside service providers to estimate the clinical trial costs incurred. Commitments The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has occurred and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount the Company accrues the minimum amount in the range. There has been no such liabilities recorded by the Company as of December 31, 2022. Leases At the commencement date of a lease, the Company recognizes lease liabilities which represent its obligation to make lease payments, and right-of-use assets ("ROU assets") which represent its right to use the underlying asset during the lease term. The lease liability is measured at the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at the lease commencement date. The ROU asset is measured at cost, which includes the initial measurement of the lease liability and initial direct costs incurred by the Company and excludes lease incentives. ROU assets are recorded in operating lease ROU assets and lease liabilities are recorded in operating lease liabilities, current and noncurrent in the balance sheets. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term. The Company does not recognize lease liabilities and ROU assets for short-term leases with terms of twelve months or less. Share-Based Compensation Share-based compensation expense represents the cost of the grant-date fair value of employee, officer, director, and non-employee stock option, employee stock purchase plan, and restricted stock unit grants, estimated in accordance with the applicable accounting guidance, recognized using the straight-line method over the vesting period for service-based options, employee stock purchase plan rights and restricted stock units and using the graded vesting method for performance-based options. The vesting period generally approximates the expected service period of the awards. Forfeitures are recognized and accounted for as they occur. The fair value of stock options and employee stock purchase plan rights are estimated using a Black-Scholes option pricing model on the date of grant. This method requires certain assumptions be used as inputs, such as the fair value of the underlying common stock, expected term of the option before exercise, expected volatility of the Company’s common stock, expected dividend yield, and a risk-free interest rate. Options granted during the year have a maximum contractual term of ten years. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The expected term of the employee stock purchase plan rights equals the six-month look-back period. The expected volatility is based upon the historical volatility of a number of publicly traded companies in similar stages of clinical development. The Company has historically not declared or paid any dividends and does not currently expect to do so in the foreseeable future. The risk-free interest rates used are based on the U.S. Department of Treasury ("U.S. Treasury") yield in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the expected term of the stock options. The fair value of restricted stock units is based on the closing price of the Company's common stock as reported on The Nasdaq Global Market on the date of grant. Income Taxes Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable 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 that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Segment Reporting The Company’s chief operating decision maker, its President and Chief Executive Officer, manages its operations and business as one operating segment for the purposes of allocating resources, makes operating decisions and evaluates financial performance. No product revenue has been generated since inception and all assets are held in the United States. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities, which include unvested common stock, unvested restricted stock options, and outstanding stock options under the Company’s equity incentive plan, have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Recent Accounting Pronouncements There were no significant updates to the recently issued accounting standards which may be applicable to the Company. Although there are several other new accounting pronouncements issued or proposed by the FASB, the Company does not believe any of those accounting pronouncements have had or will have a material impact on its financial position or operating results.

Net Loss Per Share

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Net Loss Per Share

3. Net Loss Per Share

The following tables summarize the computation of the basic and diluted net loss per share (in thousands except share and per share data):


	Year Ended December 31,
	2022			2021
Numerator:
Net loss	$	(113,837	)	$	(86,075	)
Denominator:
Weighted average common shares outstanding		43,635,044			32,901,002
Less: weighted average unvested common stock issued upon early exercise of common stock options		(3,322	)		(44,119	)
Weighted average shares used to compute net loss per share, basic and diluted		43,631,722			32,856,883
Net loss per share, basic and diluted	$	(2.61	)	$	(2.62	)

The following table summarizes the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive:


	December 31,
	2022		2021
Common stock options		5,519,275		4,204,686
Restricted stock units		356,728		—
Unvested common stock upon early exercise of common stock options		508		16,181
		5,876,511		4,220,867

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

4. Fair Value of Financial Instruments

The following tables summarize the fair value of the Company’s financial instruments (in thousands):


			Fair Value Measurements Using
	December 31, 2022		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	36,494	$	36,494	$	—	$	—
Short-term investments:
Corporate debt securities	$	88,681	$	—	$	88,681	$	—
Commercial paper		65,409		—		65,409		—
Government securities		160,559		—		160,559		—
Total short-term investments	$	314,649	$	—	$	314,649	$	—
Total	$	351,143	$	36,494	$	314,649	$	—


			Fair Value Measurements Using
	December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	57,018	$	57,018	$	—	$	—
Short-term investments:
Corporate debt securities	$	111,466	$	—	$	111,466	$	—
Commercial paper		21,272		—		21,272
U.S. Government securities		44,534		—		44,534		—
Total short-term investments	$	177,272	$	—	$	177,272	$	—
Total	$	234,290	$	57,018	$	177,272	$	—

Cash Equivalents and Short-Term Investments

Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and short-term investments consisted of commercial paper, corporate debt securities and Government securities. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers.

Investments are classified as Level 1 within the fair value hierarchy if their quoted prices are available in active markets for identical securities. Investments in money market funds of $36.5 million and $57.0 million included in cash equivalents as of December 31, 2022 and 2021, respectively, were classified as Level 1 instruments.

Investments in corporate debt securities, commercial paper and Government securities included in short-term investments are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported upon utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment

and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations.

The following tables summarize the Company’s short-term investments as of December 31, 2022 and 2021 (in thousands):


		December 31, 2022
	Maturity (in years)	Amortized Cost		Unrealized Losses			Unrealized Gains		Estimated Fair Value
Corporate debt securities	1 year or less	$	88,995	$	(320	)	$	6	$	88,681
Commercial paper	1 year or less		65,532		(123	)		—		65,409
Government securities	1 year or less		160,801		(319	)		77		160,559
Total		$	315,328	$	(762	)	$	83	$	314,649


		December 31, 2021
	Maturity (in years)	Amortized Cost		Unrealized Losses			Unrealized Gains		Estimated Fair Value
Corporate debt securities	1 year or less	$	111,548	$	(89	)	$	7	$	111,466
Commercial paper	1 year or less		21,272		—			—		21,272
U.S. Government securities	1 year or less		44,602		(68	)		—		44,534
Total		$	177,422	$	(157	)	$	7	$	177,272

The Company considers whether unrealized losses have resulted from a credit loss or other factors. The unrealized losses on the Company’s available-for-sale securities as of December 31, 2022 and 2021 were caused by fluctuations in market value and interest rates as a result of the economic environment and not credit risk. The Company concluded that an allowance for credit losses was unnecessary as of December 31, 2022 and 2021. It is neither management’s intention to sell nor is it more likely than not that the Company will be required to sell these investments prior to recovery of their cost basis or recovery of fair value, except for investments totaling $67.6 million that were sold with a realized loss of $0.3 million in January 2023. The Company recorded this $0.3 million as an impairment loss for the year ended December 31, 2022. Unrealized gains and losses are included in accumulated other comprehensive loss.

The Company excludes accrued interest from both the fair value and the amortized cost basis of the available-for-sale debt securities for the purposes of identifying and measuring an impairment and to not measure an allowance for expected credit losses for accrued interest receivables. Accrued interest receivable is written off through net realized investment gains (losses) at the time the issuer of the bond defaults or is expected to default on payment. It is the Company's policy to present the accrued interest receivable balance as part of prepaid expenses and other current assets in the balance sheets. Accrued interest receivable related to short-term investments was $0.8 million and $1.0 million as of December 31, 2022 and 2021, respectively.

- 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

Balance Sheet Components

12 Months Ended

Dec. 31, 2022

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

5. Balance Sheet Components

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets are comprised of the following (in thousands):


	December 31,
	2022		2021
Prepaid expenses	$	5,616	$	4,538
Other current assets		2,929		3,154
Total prepaid expenses and other current assets	$	8,545	$	7,692

Property and Equipment, Net

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


	December 31,
	2022			2021
Leasehold improvements	$	4,402		$	3,462
Furniture and fixtures		645			544
Research equipment		12,900			9,633
Computers and software		130			130
Construction-in-progress		49,655			2,274
Total property and equipment		67,732			16,043
Less accumulated depreciation and amortization		(5,824	)		(3,187	)
Total property and equipment, net	$	61,908		$	12,856

Depreciation and amortization expense were $2.6 million and $1.8 million for the years ended December 31, 2022 and 2021, respectively.

Accrued and Other Current Liabilities

Accrued and other current liabilities are comprised of the following (in thousands):


	December 31,
	2022		2021
Accrued compensation	$	6,691	$	5,453
Accrued research and development costs		3,486		2,280
Accrued property and equipment		5,001		96
Other accrued and current liabilities		858		1,518
Total accrued and other liabilities	$	16,036	$	9,347

Leases

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Leases

6. Leases

The Company has operating leases for its current corporate offices, laboratory space, manufacturing facility, and dedicated space in a vivarium in South San Francisco, California, as well as for an additional facility in South San Francisco that the Company plans to use for corporate offices, laboratories and manufacturing.

The components of lease expense were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Operating lease expense	$	11,220	$	2,581
Variable lease expense (1)		462		302
Short-term lease expense		45		92
Total lease expense	$	11,727	$	2,975

(1) Variable lease expense for the periods presented primarily included common area maintenance charges.

Supplemental information related to operating leases were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows used for operating leases	$	6,887	$	2,239

The weighted-average remaining lease term was 10.8 years for the corporate office and laboratory space leases as of December 31, 2022. The corporate office lease includes an option to renew for an additional seven years. However, the renewal option was not included in the lease term for calculating the lease liability, as the renewal option allows the Company to maintain operational flexibility, and the Company was not reasonably certain

that it would exercise the renewal option at the time of the lease commencement. The weighted-average discount rate was 9.8% as of December 31, 2022.

There were $59.5 million and $18.7 million in right-of-use assets obtained in exchange for operating lease liabilities resulting from new leases and from modifications of existing leases, respectively, for the year ended December 31, 2022.

Maturities of operating lease liabilities under existing operating leases as of December 31, 2022 were as follows (in thousands):


Year ending December 31,	Amount
2023	$	11,206
2024		12,671
2025		13,033
2026		13,467
2027		13,917
2028 and thereafter		87,290
Total undiscounted future minimum lease payments		151,584
Less imputed interest		(60,813	)
Less tenant improvement receivable		(7,837	)
Total operating lease liabilities	$	82,934
Operating lease liabilities:
Current		4,249
Non-current		78,685
Total lease liability	$	82,934

In May 2018, the Company entered into a lease agreement for its corporate office and laboratory space located in South San Francisco, California with an expiration date in May 2025 (the "Initial Lease Agreement"). In April 2019, the Company executed the first amendment to the Initial Lease Agreement for additional corporate space, laboratory space and manufacturing capabilities and an extension to the lease term through April 2026.

In May 2020, the Company signed a second amendment to the Initial Lease Agreement. The amended lease provides for an eight-year non-cancelable lease of additional office and laboratory space in the same building. The lease amendment for additional office and laboratory space provided for abatement of rent during the first three months of the lease and contains rent escalations during the term of the lease. The lease for this additional space commenced in January 2021 and expires in January 2029. The lease amendment also includes an extension of the lease term for the existing office and laboratory space beginning on May 1, 2020 and expiring in January 2029. The amendment to the Initial Lease Agreement also includes an option to extend the lease for an additional seven-year term.

In January 2021, the Company signed a third amendment to the Initial Lease Agreement which provides for the lease of additional space in the same building. The lease amendment for this additional space commenced in April 2021 and expires in March 2024.

In October 2021, the Company signed a fourth amendment to the Initial Lease Agreement which provides for the lease of additional space in the same building. The lease for additional office and laboratory space provides for abatement of rent during the first two months of the lease and contains rent escalations during the term of the lease. The lease amendment of this additional space commenced in April 2022 and expires in January 2029. The lease amendment also includes this additional space in the Company’s option to extend the amended Initial Lease Agreement for an additional seven-year term. The other terms of the Initial Lease Agreement, as amended, remain unchanged.

In July 2021, the Company entered into a lease agreement for corporate office, manufacturing and laboratory space located in South San Francisco, California with an expiration date approximately twelve years after the lease's legal commencement date (the "Additional Lease Agreement"). The lease for this additional space and the

Company's obligation to pay rent commenced in January 2022. In addition to base rent, the Company is responsible for payment of direct expenses, which include operating, insurance and tax expenses. The lease also provides for certain tenant improvement allowances of up to approximately $25.2 million for tenant improvements and certain infrastructure upgrades in connection with the initial buildout of the premises, approximately $4.4 million of which, if utilized, would need to be repaid by the Company over the lease term. In 2021, the Company delivered a security deposit in the form of a letter of credit of $1.6 million to the Landlord in connection with the Additional Lease Agreement.

In November 2021, the Company entered into an amendment to the Additional Lease Agreement. The lease amendment expressly includes manufacturing as a permitted use at the facility, clarifies that Silicon Valley Bank is an acceptable bank for purposes of issuing a letter of credit under the lease, revises the letter of credit transferability terms and replaces the form of letter of credit attached to the lease.

In August 2022, the Company entered into fifth amendment to the Initial Lease Agreement and a second amendment to the Additional Lease Agreement for its existing facilities in South San Francisco, California. The fifth amendment to the Initial Lease Agreement includes an extension of the lease term for certain of the Company's existing facilities through July 31, 2030. The second amendment to the Additional Lease Agreement provides for approximately $15.0 million of additional tenant improvement allowances, in addition to the tenant improvement allowances of $25.2 million included in the original Additional Lease Agreement, and increases the base rent payments over the existing term of the lease.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

7. Commitments and Contingencies

Guarantee Agreement

The Company has agreements whereby it indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The term of the indemnification period is for the officer’s or director’s lifetime. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited; however, the Company has a director and officer insurance policy that limits its exposure and enables the Company to recover a portion of any future amounts under certain circumstances and subject to deductibles and exclusions. The Company had no liabilities recorded for these agreements as of December 31, 2022 and 2021.

Letters of Credit

The Company has $2.7 million in letter of credit agreements with a financial institution that are used as collateral for the Company’s corporate headquarters’ operating lease and the additional facility in South San Francisco that the Company plans to use for corporate offices, laboratories and manufacturing. The letters of credit automatically renew annually without amendment unless cancelled by the financial institutions within 30 to 60 days of the annual expiration date.

Collaboration and License Agreements

12 Months Ended

Dec. 31, 2022

Collaboration Agreement [Abstract]

Collaboration and License Agreements

8. Collaboration and License Agreements

CRISPR Collaboration Agreement

On May 5, 2021, the Company entered into the CRISPR Agreement with CRISPR to co-develop and co-commercialize an engineered CAR NK product candidate targeting the CD70 tumor antigen and a second novel NK plus T cell product candidate. In addition, the Company has received licenses from CRISPR for three CRISPR-Cas9 gene editing targets and will receive a license from CRISPR for up to two more CRISPR-Cas9 gene editing targets that can be engineered into an unlimited number of its own NK cell products. CRISPR also has an option to co-develop and co-commercialize a future CAR NK program.

Under the terms of the CRISPR Agreement, the Company and CRISPR share equally in all research and development costs and potential profits worldwide related to the NKX070 product candidate, NK+T product candidate, and the potential future CAR NK program. For the NK+T program, CRISPR is responsible for gene-editing activities and T cell related activities, and Nkarta is responsible for NK cell related activities. The related impact of the cost sharing associated with the research and development activities is included in research and

development expense on the condensed statements of operations. Expenses related to services performed by the Company are classified as research and development expense. Payments received from CRISPR for partial reimbursement of expenses are recorded as a reduction of research and development expense. Reduction of research and development expense resulting from partial reimbursement from CRISPR was $4.2 million and $2.3 million for the years ended December 31, 2022 and 2021, respectively. As of December 31, 2022, the Company had a $1.3 million receivable under the research cost sharing provision, which is included as part of prepaid expenses and other current assets in the condensed balance sheet.

For each non-collaboration product candidate incorporating a genome editing target licensed from CRISPR (a "CRISPR-licensed product candidate"), the Company would retain worldwide rights and may be required to make potential future payments based on the achievement of development and regulatory approval milestones totaling less than mid-twenty million dollars for each CRISPR-licensed product candidate, as well as tiered royalties up to the mid-single digits on net product sales of such product. Further, for each CRISPR-licensed product candidate targeting a specified tumor antigen, the Company may be required to make potential future payments based on the achievement of development and regulatory approval milestones totaling less than high-forty million dollars for each CRISPR-licensed product candidate targeting the specified tumor antigen, as well as tiered royalties up to the mid-single digits on net product sales of such product. As of December 31, 2022, the Company has not paid any amounts nor are any amounts owed by the Company under the CRISPR Agreement, and no milestones have been achieved.

MaxCyte License Agreement

On October 26, 2021, the Company entered into a license agreement (the "MaxCyte Agreement") with MaxCyte, Inc. ("MaxCyte") to obtain non-exclusive clinical and commercial rights to use MaxCyte's cell loading technology to develop and commercialize in up to ten licensed products.

In connection with the MaxCyte Agreement, the Company must pay to MaxCyte annual research license fees and commercialization license fees, ranging from $0.1 million to $0.3 million, for each instrument licensed by the Company. Further, the Company could be required to make milestone payments to MaxCyte upon completion of certain regulatory and commercial milestones related to the clinical development and commercialization of certain of the Company’s licensed products. The aggregate potential milestone payments range from $10 million to $13 million per licensed product. Additionally, the Company may be required to make net sales milestone payments totaling between $61.9 million to $116.8 million per licensed product. As of December 31, 2022, no milestones have been achieved.

University of Singapore and St. Jude Children’s License Agreement

In August 2016, the National University of Singapore ("NUS") and St. Jude Children’s Research Hospital ("St. Jude") and the Company entered into a license agreement under which NUS and St. Jude (the "Licensors") granted the Company an exclusive, royalty-bearing, worldwide license to its patent rights related to a method for expanding natural killer cells; a chimeric receptor with NKG2D specificity; and a method for supporting autonomous natural killer cell function ("NUS and St. Jude License Agreement"). The NUS and St. Jude License Agreement provides the Company with the rights to grant and authorize sublicenses to make, have made, use, sell, offer for sale and import products and otherwise exploit the patent rights.

As consideration for the license, the Company made an upfront payment of $31,800 and issued NUS 250,000 shares of the Company’s common stock. The Company determined that the upfront payment (SGD 42,750) and value of the common stock issued ($2,500 based on fair value at time of issuance) as part of the license agreement would be expensed upon execution of the contract as the license was acquired for research and development purposes which does not have alternative future uses, and the underlying technology has not reached technological feasibility, hence the Company expensed these costs during 2016.

In addition, the Company is required to pay an annual license maintenance fee of SGD 25,000, increasing to SGD 50,000 after year two of the agreement. Further, the Company could be required to make milestone payments to the Licensors upon completion of certain regulatory and commercial milestones related to the clinical development and commercialization of certain of the Company’s product candidates. The aggregate potential

milestone payments are approximately SGD 5 million. The Company has also agreed to pay the Licensors royalties of 2.5% of net sales of products sold by the Company or through a sublicense. Additionally, the Company agreed to pay the Licensors a tiered percentage of sublicensing income (ranging from 7.5% to 20%) based on the timing of capital raised and stage of clinical trials. The NUS and St. Jude License Agreement also includes certain performance objectives which obligate the Company to meet various milestones related to the clinical development and commercialization of certain of the Company’s product candidates over time for up to 120 months after the effective date of the NUS and St. Jude License Agreement.

The Company recorded $37,000 license maintenance fees included as part of research and development expenses for each of the years ended December 31, 2022 and 2021.

Employee Benefits

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

Employee Benefits

9. Employee Benefits

On January 1, 2018, the Company adopted a defined contribution 401(k) plan that is available to eligible employees. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation, limited to the maximum amount allowable under federal tax regulations. As part of the plan, the Company elected to make non-matching contributions via mandatory 3% of compensation safe harbor nonelective contributions. The Company recognized $0.8 million and $0.6 million for expense related to the nonelective 401(k) contributions for the years ended December 31, 2022 and 2021, respectively.

Stockholders' Equity

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Stockholders' Equity

10. Stockholders’ Equity

Under the Amended and Restated Certificate of Incorporation dated July 14, 2020, the Company had a total of 100,000,000 authorized shares of common stock with a par value of $0.0001 per share and 54,350,179 authorized shares of preferred stock with a par value of $0.0001 per share.

Common Stock

On August 12, 2021, the Company filed a Registration Statement on Form S-3 (the "Shelf Registration Statement"), covering the offer and sale from time to time, pursuant to Rule 415 of the Securities Act of 1933, as amended (the "Securities Act"), of up to $500.0 million in aggregate offering price of shares of the Company’s common stock, shares of the Company’s preferred stock, debt securities, warrants, and rights and units. The Shelf Registration Statement was declared effective by the Securities and Exchange Commission (the "SEC") on September 2, 2021. The Shelf Registration Statement included a prospectus covering the offer and sale from time to time of up to $150.0 million in aggregate offering price of shares of the Company’s common stock through an “at-the-market” equity offering program (the "ATM Offering Program") with Cowen and Company, LLC, as sales agent. As of December 31, 2022, the Company has issued and sold 113,213 shares of its common stock pursuant to the ATM Offering Program, resulting in net proceeds of approximately $1.6 million, after deducting offering expenses.

On April 28, 2022, the Company issued and sold 15,333,334 shares of its common stock in an underwritten public offering, including 2,000,000 shares associated with the full exercise of the underwriters’ option to purchase additional shares, at a price to the public of $15.00 per share. The total net proceeds to the Company from the offering were approximately $215.3 million, after deducting underwriting discounts and commissions and offering expenses. The shares were issued pursuant to the Company’s Shelf Registration Statement.

- 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 14
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.3-04)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Paragraph 18
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-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Share-Based Compensation

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Share-Based Compensation

11. Share-Based Compensation

Equity Incentive Plan

2015 Equity Incentive Plan

The Company granted options under its 2015 Equity Incentive Plan (the "2015 Plan"). The 2015 Plan allowed for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock unit

awards and other stock awards, although only stock options were awarded under the 2015 Plan. Awards could be made to officers, directors, employees, non-employee directors, and consultants of the Company. In connection with the Board of Directors’ and stockholders’ approval of the 2020 Plan, the 2015 Plan was terminated as to future awards and any options then outstanding under the 2015 Plan remained outstanding and effective. As of December 31, 2022, there were an aggregate of 1,344,048 shares of common stock issuable upon the exercise of outstanding options issued under the 2015 Plan.

2020 Performance Incentive Plan

The Company’s 2020 Performance Incentive Plan (the "2020 Plan") which was adopted by the Company’s board of directors in June 2020 and approved by the Company’s stockholders in July 2020, became effective upon the consummation of the IPO in July 2020. The 2020 Plan allows for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, stock bonuses, restricted stock, stock units and other forms of awards including cash awards to its officers, directors, employees, consultants and advisors.

As of December 31, 2022, a total of 5,945,002 shares of the Company’s common stock were authorized for issuance with respect to awards granted under the 2020 Plan (this number of shares gives effect to the annual increases in the 2020 Plan share limit, as described in the next sentence). The share limit will automatically increase on the first trading day in January of each year by an amount equal to the lesser of (1) 5% of the total number of outstanding shares of the Company’s common stock on the last trading day in December in the prior year, or (2) such lesser number as determined by the Company’s board of directors. Any shares subject to awards granted under the 2020 Plan or the 2015 Plan that are not paid, delivered or exercised before they expire or are canceled or terminated, or otherwise fail to vest, as well as shares used to pay the purchase or exercise price of such awards or related tax withholding obligations, will become available for new award grants under the 2020 Plan. A total of 1,775,102 shares was available for issuance under the 2020 Plan as of December 31, 2022.

The following table summarizes the stock option activity during the year ended December 31, 2022 (in thousands, except number of shares, exercise prices and contractual term):


	Number of shares			Weighted-average exercise price		Weighted-average remaining contractual term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021		4,204,686		$	19.19		8.2
Granted		2,327,820			12.61
Exercised		(383,120	)		3.62
Forfeited		(630,111	)		21.99
Outstanding at December 31, 2022		5,519,275		$	17.17		8.1	$	2,915
Exercisable at December 31, 2022		2,337,753		$	17.49		7.4	$	1,957
Vested and expected to vest at December 31, 2022		5,519,275		$	17.17		8.1	$	2,915

The aggregate intrinsic value represents the difference between the exercise price of stock options and the quoted closing market price of the Company’s common stock on the applicable date for all in-the-money stock options.

Additional information related to the Company’s stock options is summarized below (in thousands, except per share amounts):


	Year Ended December 31,
	2022		2021
Weighted-average grant-date fair value of stock option grants per share	$	8.60	$	30.87
Intrinsic value of options exercised	$	4,268	$	9,991

The following table summarizes the restricted stock unit activity during the year ended December 31, 2022:


	Number of shares			Weighted-average grant date fair value per share		Weighted- average remaining contractual term (in years)
Outstanding at December 31, 2021		—		$	—
Granted		389,388			12.62
Forfeited		(32,660	)		12.15
Vested		—			—
Outstanding at December 31, 2022		356,728		$	12.66		1.7

Employee Stock Purchase Plan

The Company’s 2020 Employee Stock Purchase Plan (the "ESPP"), which was adopted by the Company’s board of directors in June 2020 and approved by the Company’s stockholders in July 2020, became effective upon the consummation of the IPO. A total of 952,524 shares of the Company’s common stock were authorized for issuance under the ESPP. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. During 2022, 61,754 shares were issued under the ESPP resulting in aggregate cash proceeds of $0.4 million. There were no ESPP purchases in 2021. As of December 31, 2022, 890,770 shares remained available for issuance under the ESPP (after giving effect to share purchases made under the ESPP through and including the ESPP offering period that ended on November 30, 2022).

Liability for Early Exercise of Restricted Stock Options

Certain individuals were granted the ability to early exercise their stock options. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest in accordance with the original vesting schedule. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options on the accompanying balance sheets and will be transferred into common stock and additional paid-in capital as the shares vest. Shares subject to repurchase by the Company were 508 shares and 16,181 shares, as of December 31, 2022 and 2021, respectively, and in each case the related liability recorded under other accrued and other current liabilities in the condensed balance sheets was insignificant.

Common Stock Reserved for Future Issuance

As of December 31, 2022, the Company had reserved the following shares of common stock for future issuance:


	December 31, 2022
Common stock options and restricted stock units granted and outstanding		5,876,003
Reserved for future equity award grants		1,775,102
Reserved for future ESPP issuances		890,770
		8,541,875

Share-Based Compensation Expense

Share-based compensation expense for the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Research and development	$	7,326	$	6,719
General and administrative		9,530		7,742
Total share-based compensation expense	$	16,856	$	14,461

The total unrecognized compensation cost related to stock options was $34.2 million, which is expected to be recognized over a weighted-average remaining service period of 2.5 years as of December 31, 2022. The total unrecognized compensation cost related to restricted stock units was $3.7 million, which is expected to be recognized over a weighted-average remaining service period of 3.2 years as of December 31, 2022. As of December 31, 2022, there was $0.1 million of unrecognized compensation cost related to ESPP, which is expected to be recognized over a weighted-average remaining service period of .4 years.

Fair Value Disclosures

The fair value of stock options was estimated on the date of grant using the Black-Scholes option pricing model with the following range of assumptions:


	Year Ended December 31,
	2022	2021
Options
Common stock fair value	$5.99 - $18.44	$15.35 - $54.89
Risk-free interest rate	1.6% - 4.2%	0.6% - 1.4%
Expected volatility	75.7% - 78.9%	77.3% - 79.9%
Expected term (in years)	5.5 - 6.1	5.5 - 6.1
Expected dividend yield	—	—
ESPP
Risk-free interest rate	1.6% - 4.7%	—
Expected volatility	63.8% - 151.9%	—
Expected term (in years)	0.5	—
Expected dividend yield	—	—

The Company recognizes compensation costs related to stock options granted to employees and nonemployees based on the estimated fair value of the awards on the date of grant, net of forfeitures. The Company generally recognizes grant-date fair value of stock options granted to employees and non-employee service providers on a straight-line basis over the requisite service period, which is generally the vesting term of the respective awards. The Company determines the fair value of stock options with a service and performance condition, or performance-based options, based on the fair value of the Company’s common stock on the date of grant. The Company accounts for the impact of forfeitures as they occur. For purposes of calculating share-based compensation, the Company estimates the fair value of stock options issued using a Black-Scholes option-pricing model. The determination of the fair value of share-based payment awards utilizing the Black-Scholes option-pricing model is affected by the Company’s stock price and a number of assumptions, including expected volatility, expected life, risk-free interest rate and expected dividends.

Expected term. The Company opted to use the “simplified method” for estimating the expected term of employee options, whereby the expected term equals the average of the vesting term and the original contractual term of the option (generally 10 years).

Expected volatility. Due to the Company’s limited operating history and a lack of company specific historical and implied volatility data, the Company based its estimate of expected volatility on the historical volatilities of the common stock of comparable publicly traded biopharmaceutical 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, and financial leverage to the Company.

Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments with maturities similar to the expected term of the stock options.

Expected dividend yield. The Company has not issued any dividends and do not expect to issue dividends over the life of the options, as a result the estimated dividend yield is zero.

Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

Due to the Company’s net losses for the years ended December 31, 2022 and 2021, and since the Company has a full valuation allowance against deferred tax assets, there was no tax provision or benefit for income taxes recorded in the years presented other than minimum amounts required for state tax purposes.

A reconciliation on income taxes to the amount computed by applying the statutory federal income tax rate to the net loss is summarized as follows (in thousands):


	Year Ended December 31,
	2022			2021
Income tax benefit at statutory rates	$	(23,906	)	$	(18,076	)
State income tax, net of federal benefit		(1,566	)		(1,005	)
Permanent items		1,891			592
Research and development credits		(3,426	)		(1,661	)
Other		—			(515	)
Change in valuation allowance		27,007			20,665
Income tax expense	$	—		$	—

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


	December 31,
	2022			2021
Deferred tax assets:
Net operating loss carry forwards	$	36,732		$	33,767
Depreciation and amortization		316			268
Research and development credits		11,999			6,984
Share-based compensation		3,552			2,245
Accrued expenses		1,367			1,189
Lease liability		19,062			2,616
Other, net		35			34
Section 174 Capitalized R&D		17,352			—
Total deferred tax assets		90,415			47,103
Valuation allowance for deferred tax assets		(71,368	)		(44,361	)
Deferred tax assets, net of valuation allowance		19,047			2,742
Deferred tax liabilities:
Right-of-use asset		(18,089	)		(2,471	)
Depreciation and amortization		(958	)		(271	)
Net deferred tax assets	$	—		$	—

The Company has a net operating loss and has provided a valuation allowance against net deferred tax assets due to uncertainties regarding the Company’s ability to realize these assets. The valuation allowance increased by $27.0 million and $20.7 million as of December 31, 2022 and 2021, respectively.

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 the temporary differences

representing net future deductible amounts become deductible. Due to the Company’s history of losses, and lack of other positive evidence, the Company has determined that it is more likely than not that its net deferred tax assets will not be realized, and therefore, the net deferred tax assets are substantially offset by a valuation allowance at December 31, 2022 and 2021. The deferred tax assets were primarily comprised of federal and state tax net operating losses and tax credit carryforwards.

As of December 31, 2022, the Company had net operating loss ("NOL") carryforwards of approximately $153.3 million and $65.1 million, available to reduce future taxable income, if any, for federal and California state income tax purposes, respectively. Of the $153.3 million federal NOL carryforwards, $0.2 million and $3.0 million will begin expiring in 2035 and 2036, respectively, if not utilized, while $150.1 million can be carried forward indefinitely. The state NOL carryforwards will begin expiring in 2036, if not utilized.

The Company also had federal and state research and development credit carry forwards of approximately $9.9 million and $5.6 million, respectively, at December 31, 2022. The federal credits will begin expiring in 2035 if not utilized. The California credits have no expiration date.

Utilization of the NOL and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that may have occurred or that could occur in the future, as required by Section 382 of the Internal Revenue Code of 1986, as amended (the "Code"), as well as similar state provisions. The future utilization of the Company’s NOL and tax credit carryforwards to offset future taxable income may be subject to a substantial annual limitation as a result of changes in ownership by stockholders that hold 5% or more of the Company’s common stock. An assessment of such ownership changes under Section 382 was not completed through December 31, 2019. To the extent that an assessment is completed in the future, the Company’s ability to utilize tax attributes could be restricted on a year-by-year basis and certain attributes could expire before they are utilized. The Company will examine the impact of any potential ownership changes in the future.

The Company has not been audited by the Internal Revenue Service or any state income or franchise tax agency. As of December 31, 2022, its federal and state returns for the years ended 2015 through the current period are still open to examination. In addition, all of the net operating losses and research and development credit carryforwards that may be used in future years are still subject to inquiry given that the statute of limitation for these items would begin in the year of the utilization. The balance of gross unrecognized tax benefits as of December 31, 2022 and 2021 was approximately $2.3 million and $1.4 million, respectively, all of which would affect the Company’s income tax expense if recognized, before consideration of the Company’s valuation allowance. The Company does not expect its unrecognized tax benefits to change significantly over the next 12 months. The Company recognizes interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. There was no interest and penalties for the years ended December 31, 2022 and 2021. The Company files income tax returns in the United States federal jurisdiction and the State of California and is not currently under examination by any taxing authority for any open tax year. Due to net operating loss carryforwards, all years remain open for income tax examination. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the IRS or state tax authorities to the extent utilized in a future period. No federal or state tax audits are currently in process.

The following table summarizes the changes in the Company’s gross unrecognized tax benefits (in thousands):


	December 31,
	2022			2021
Balance at the beginning of the year	$	1,359		$	777
Increases (decreases) related to tax positions taken in prior years		(43	)		(281	)
Increases related to tax positions taken in current year		1,023			863
Balance at the end of the year	$	2,339		$	1,359

- Definition

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

+ References

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

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

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

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

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

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

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

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

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

+ Details

Subsequent Events

12 Months Ended

Dec. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

13. Subsequent Events

On March 10, 2023, Silicon Valley Bank ("SVB") in the United States was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation ("FDIC") as receiver. On March 12, 2023, the U.S. Department of the Treasury, Federal Reserve, and FDIC jointly announced that the FDIC will complete its resolution of SVB in a manner that fully protects all depositors. As of March 10, 2023, we held $2.7 million in collateral money market accounts supporting letters of credit issued by SVB to the Landlord in connection with the Initial Lease Agreement and Additional Lease Agreement. We are working with the Landlord to replace the letters of credit issued by SVB with letters of credit from a different financial institution.

Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principle ("U.S. GAAP").
COVID-19 Pandemic	COVID-19 Pandemic The COVID-19 pandemic has caused disruptions in the global economy and has affected and may in the future affect the Company’s business and operations in the future. In response to the pandemic, the Coronavirus Aid, Relief and Economic Security Act (the "CARES Act") was signed into law on March 27, 2020. The CARES Act, among other things, includes tax provisions relating to refundable payroll tax credits, deferment of employer’s social security payments, net operating loss utilization and carryback periods, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. The CARES Act had no impact on the Company’s income tax provision for the year ended December 31, 2022. The Company continues to evaluate the impact of the CARES Act on its financial position, results of operations and cash flows.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to preclinical studies, fair value of assets and liabilities, share-based compensation and income taxes. Management bases its estimates on historical experience, knowledge of current events and actions it may undertake in the future that management believes to be reasonable under the circumstances. Actual results may differ from these estimates and assumptions.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially subject the Company to concentration of credit risk, consist primarily of cash, cash equivalents and short-term investments. The Company maintains cash, cash equivalents and short-term investments with various high credit quality and are invested through banks and other financial institutions in the United States. Such deposits may be in excess of federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company has not experienced any losses on deposits since inception.
Comprehensive Loss	Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company displays comprehensive loss and its components as part of the statements of operations and comprehensive loss.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The accounting guidance defines fair value, establishes a consistent framework for measuring fair value, and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of prepaid expenses and other current assets, accounts payable, accrued liabilities and other current liabilities are reasonable estimates of their fair value due to the short-term nature of these accounts.
Cash, Cash Equivalents, Short-term Investments and Restricted Cash	Cash, Cash Equivalents, Short-term Investments and Restricted Cash Cash and Cash Equivalents The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash includes demand deposits held in readily available checking accounts at a federally insured financial institution. Cash equivalents consist of money market funds. Short-term Investments Short-term investments consist of commercial debt securities, commercial paper and Government securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified most of its available-for-sale investment securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value, and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. The cost of debt securities is adjusted for amortization of purchase premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income in the statements of operations and comprehensive loss. Realized gains and losses on sales of securities are determined using the specific identification method and recorded in other income (expense), net in the statement of operations and comprehensive loss. Restricted Cash The Company is required to maintain letters of credit related to its office and lab space lease and the additional facility in South San Francisco that the Company plans to use for corporate offices, laboratories and manufacturing. This cash is the collateral for those letters of credit and per the terms of the leases, must remain in place until one to two months after the termination of the leases. As the remaining terms of the leases as of December 31, 2022 is greater than one year, the related restricted cash has been classified as non-current.
Property and Equipment, Net	Property and Equipment, Net Property and equipment, which consist of leasehold improvements, furniture and fixtures, research equipment, computers and software and construction-in-progress are stated at cost less accumulated depreciation. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which ranges from three to five years. Leasehold improvements are amortized over the remaining life of the lease for leasehold improvements at the time the asset is placed into service.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The carrying value of long-lived assets, including property and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the asset may not be recoverable. An impairment loss is recognized when the total of estimated future undiscounted cash flows, expected to result from the use of the asset and its eventual disposition, are less than its carrying amount. Impairment, if any, would be assessed using discounted cash flows or other appropriate measures of fair value. Through December 31, 2022, there has been no such impairment losses recorded by the Company.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and other benefits of research and development personnel, including associated share-based compensation, costs related to research activities, preclinical studies, clinical trial, drug manufacturing and allocated overhead and facility-related expenses. The Company accounts for non-refundable advance payments for goods or services that will be used in future research and development activities as expenses when the goods have been received or when the service has been performed rather than when the payment is made. Clinical trial costs are a component of research and development expenses. The Company expenses costs for its clinical trial activities performed by third parties, including clinical research organizations and other service providers, as they are incurred, based upon estimates of the work completed over the life of the individual study in accordance with associated agreements. The Company uses information it receives from internal personnel and outside service providers to estimate the clinical trial costs incurred.
Commitments	Commitments The Company recognizes a liability with regard to loss contingencies when it believes it is probable a liability has occurred and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount the Company accrues the minimum amount in the range. There has been no such liabilities recorded by the Company as of December 31, 2022.
Leases	Leases At the commencement date of a lease, the Company recognizes lease liabilities which represent its obligation to make lease payments, and right-of-use assets ("ROU assets") which represent its right to use the underlying asset during the lease term. The lease liability is measured at the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at the lease commencement date. The ROU asset is measured at cost, which includes the initial measurement of the lease liability and initial direct costs incurred by the Company and excludes lease incentives. ROU assets are recorded in operating lease ROU assets and lease liabilities are recorded in operating lease liabilities, current and noncurrent in the balance sheets. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term. The Company does not recognize lease liabilities and ROU assets for short-term leases with terms of twelve months or less.
Share-Based Compensation	Share-Based Compensation Share-based compensation expense represents the cost of the grant-date fair value of employee, officer, director, and non-employee stock option, employee stock purchase plan, and restricted stock unit grants, estimated in accordance with the applicable accounting guidance, recognized using the straight-line method over the vesting period for service-based options, employee stock purchase plan rights and restricted stock units and using the graded vesting method for performance-based options. The vesting period generally approximates the expected service period of the awards. Forfeitures are recognized and accounted for as they occur. The fair value of stock options and employee stock purchase plan rights are estimated using a Black-Scholes option pricing model on the date of grant. This method requires certain assumptions be used as inputs, such as the fair value of the underlying common stock, expected term of the option before exercise, expected volatility of the Company’s common stock, expected dividend yield, and a risk-free interest rate. Options granted during the year have a maximum contractual term of ten years. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The expected term of the employee stock purchase plan rights equals the six-month look-back period. The expected volatility is based upon the historical volatility of a number of publicly traded companies in similar stages of clinical development. The Company has historically not declared or paid any dividends and does not currently expect to do so in the foreseeable future. The risk-free interest rates used are based on the U.S. Department of Treasury ("U.S. Treasury") yield in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the expected term of the stock options. The fair value of restricted stock units is based on the closing price of the Company's common stock as reported on The Nasdaq Global Market on the date of grant.
Income Taxes	Income Taxes Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable 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 that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
Segment Reporting	Segment Reporting The Company’s chief operating decision maker, its President and Chief Executive Officer, manages its operations and business as one operating segment for the purposes of allocating resources, makes operating decisions and evaluates financial performance. No product revenue has been generated since inception and all assets are held in the United States.
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 common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities, which include unvested common stock, unvested restricted stock options, and outstanding stock options under the Company’s equity incentive plan, have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position.
Recent Accounting Pronouncements	Recent Accounting Pronouncements There were no significant updates to the recently issued accounting standards which may be applicable to the Company. Although there are several other new accounting pronouncements issued or proposed by the FASB, the Company does not believe any of those accounting pronouncements have had or will have a material impact on its financial position or operating results.

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss Per Share

The following tables summarize the computation of the basic and diluted net loss per share (in thousands except share and per share data):


	Year Ended December 31,
	2022			2021
Numerator:
Net loss	$	(113,837	)	$	(86,075	)
Denominator:
Weighted average common shares outstanding		43,635,044			32,901,002
Less: weighted average unvested common stock issued upon early exercise of common stock options		(3,322	)		(44,119	)
Weighted average shares used to compute net loss per share, basic and diluted		43,631,722			32,856,883
Net loss per share, basic and diluted	$	(2.61	)	$	(2.62	)

Summarizes the Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share

The following table summarizes the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive:


	December 31,
	2022		2021
Common stock options		5,519,275		4,204,686
Restricted stock units		356,728		—
Unvested common stock upon early exercise of common stock options		508		16,181
		5,876,511		4,220,867

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

Summary of Fair Value of Financial Instrument

The following tables summarize the fair value of the Company’s financial instruments (in thousands):


			Fair Value Measurements Using
	December 31, 2022		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	36,494	$	36,494	$	—	$	—
Short-term investments:
Corporate debt securities	$	88,681	$	—	$	88,681	$	—
Commercial paper		65,409		—		65,409		—
Government securities		160,559		—		160,559		—
Total short-term investments	$	314,649	$	—	$	314,649	$	—
Total	$	351,143	$	36,494	$	314,649	$	—


			Fair Value Measurements Using
	December 31, 2021		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	57,018	$	57,018	$	—	$	—
Short-term investments:
Corporate debt securities	$	111,466	$	—	$	111,466	$	—
Commercial paper		21,272		—		21,272
U.S. Government securities		44,534		—		44,534		—
Total short-term investments	$	177,272	$	—	$	177,272	$	—
Total	$	234,290	$	57,018	$	177,272	$	—

Short-term investments

Schedule of Short-term Investments

The following tables summarize the Company’s short-term investments as of December 31, 2022 and 2021 (in thousands):


		December 31, 2022
	Maturity (in years)	Amortized Cost		Unrealized Losses			Unrealized Gains		Estimated Fair Value
Corporate debt securities	1 year or less	$	88,995	$	(320	)	$	6	$	88,681
Commercial paper	1 year or less		65,532		(123	)		—		65,409
Government securities	1 year or less		160,801		(319	)		77		160,559
Total		$	315,328	$	(762	)	$	83	$	314,649


		December 31, 2021
	Maturity (in years)	Amortized Cost		Unrealized Losses			Unrealized Gains		Estimated Fair Value
Corporate debt securities	1 year or less	$	111,548	$	(89	)	$	7	$	111,466
Commercial paper	1 year or less		21,272		—			—		21,272
U.S. Government securities	1 year or less		44,602		(68	)		—		44,534
Total		$	177,422	$	(157	)	$	7	$	177,272

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2022

Balance Sheet Related Disclosures [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets are comprised of the following (in thousands):


	December 31,
	2022		2021
Prepaid expenses	$	5,616	$	4,538
Other current assets		2,929		3,154
Total prepaid expenses and other current assets	$	8,545	$	7,692

Schedule of Property and Equipment, Net

roperty and equipment, net is comprised of the following (in thousands):


	December 31,
	2022			2021
Leasehold improvements	$	4,402		$	3,462
Furniture and fixtures		645			544
Research equipment		12,900			9,633
Computers and software		130			130
Construction-in-progress		49,655			2,274
Total property and equipment		67,732			16,043
Less accumulated depreciation and amortization		(5,824	)		(3,187	)
Total property and equipment, net	$	61,908		$	12,856

Schedule of Accrued Other Current Liabilities

Accrued and other current liabilities are comprised of the following (in thousands):


	December 31,
	2022		2021
Accrued compensation	$	6,691	$	5,453
Accrued research and development costs		3,486		2,280
Accrued property and equipment		5,001		96
Other accrued and current liabilities		858		1,518
Total accrued and other liabilities	$	16,036	$	9,347

Leases (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Components of Lease Expense

The components of lease expense were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Operating lease expense	$	11,220	$	2,581
Variable lease expense (1)		462		302
Short-term lease expense		45		92
Total lease expense	$	11,727	$	2,975

(1) Variable lease expense for the periods presented primarily included common area maintenance charges.

Schedule of Supplemental Information related to Operating Leases

Supplemental information related to operating leases were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows used for operating leases	$	6,887	$	2,239

Schedule of Maturities of Operating Lease Liabilities

Maturities of operating lease liabilities under existing operating leases as of December 31, 2022 were as follows (in thousands):


Year ending December 31,	Amount
2023	$	11,206
2024		12,671
2025		13,033
2026		13,467
2027		13,917
2028 and thereafter		87,290
Total undiscounted future minimum lease payments		151,584
Less imputed interest		(60,813	)
Less tenant improvement receivable		(7,837	)
Total operating lease liabilities	$	82,934
Operating lease liabilities:
Current		4,249
Non-current		78,685
Total lease liability	$	82,934

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Stock Option Activity

The following table summarizes the stock option activity during the year ended December 31, 2022 (in thousands, except number of shares, exercise prices and contractual term):


	Number of shares			Weighted-average exercise price		Weighted-average remaining contractual term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021		4,204,686		$	19.19		8.2
Granted		2,327,820			12.61
Exercised		(383,120	)		3.62
Forfeited		(630,111	)		21.99
Outstanding at December 31, 2022		5,519,275		$	17.17		8.1	$	2,915
Exercisable at December 31, 2022		2,337,753		$	17.49		7.4	$	1,957
Vested and expected to vest at December 31, 2022		5,519,275		$	17.17		8.1	$	2,915

Summary of Additional Information Related to Stock Options

Additional information related to the Company’s stock options is summarized below (in thousands, except per share amounts):


	Year Ended December 31,
	2022		2021
Weighted-average grant-date fair value of stock option grants per share	$	8.60	$	30.87
Intrinsic value of options exercised	$	4,268	$	9,991

Summary of Restricted Stock Unit Activity

The following table summarizes the restricted stock unit activity during the year ended December 31, 2022:


	Number of shares			Weighted-average grant date fair value per share		Weighted- average remaining contractual term (in years)
Outstanding at December 31, 2021		—		$	—
Granted		389,388			12.62
Forfeited		(32,660	)		12.15
Vested		—			—
Outstanding at December 31, 2022		356,728		$	12.66		1.7

Summary of Common Stock Reserved For Future Issuance

As of December 31, 2022, the Company had reserved the following shares of common stock for future issuance:


	December 31, 2022
Common stock options and restricted stock units granted and outstanding		5,876,003
Reserved for future equity award grants		1,775,102
Reserved for future ESPP issuances		890,770
		8,541,875

Summary of Share-based Compensation Expense

Share-based compensation expense for the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Year Ended December 31,
	2022		2021
Research and development	$	7,326	$	6,719
General and administrative		9,530		7,742
Total share-based compensation expense	$	16,856	$	14,461

Schedule of Fair Value of Stock Options Estimated on Date of Grant Using Black-Scholes Option Pricing Model

The fair value of stock options was estimated on the date of grant using the Black-Scholes option pricing model with the following range of assumptions:


	Year Ended December 31,
	2022	2021
Options
Common stock fair value	$5.99 - $18.44	$15.35 - $54.89
Risk-free interest rate	1.6% - 4.2%	0.6% - 1.4%
Expected volatility	75.7% - 78.9%	77.3% - 79.9%
Expected term (in years)	5.5 - 6.1	5.5 - 6.1
Expected dividend yield	—	—
ESPP
Risk-free interest rate	1.6% - 4.7%	—
Expected volatility	63.8% - 151.9%	—
Expected term (in years)	0.5	—
Expected dividend yield	—	—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Reconciliation on Income Taxes Amount Computed by Applying Statutory Federal Income Tax Rate to Net Loss

A reconciliation on income taxes to the amount computed by applying the statutory federal income tax rate to the net loss is summarized as follows (in thousands):


	Year Ended December 31,
	2022			2021
Income tax benefit at statutory rates	$	(23,906	)	$	(18,076	)
State income tax, net of federal benefit		(1,566	)		(1,005	)
Permanent items		1,891			592
Research and development credits		(3,426	)		(1,661	)
Other		—			(515	)
Change in valuation allowance		27,007			20,665
Income tax expense	$	—		$	—

Significant Components of Deferred Tax Assets

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


	December 31,
	2022			2021
Deferred tax assets:
Net operating loss carry forwards	$	36,732		$	33,767
Depreciation and amortization		316			268
Research and development credits		11,999			6,984
Share-based compensation		3,552			2,245
Accrued expenses		1,367			1,189
Lease liability		19,062			2,616
Other, net		35			34
Section 174 Capitalized R&D		17,352			—
Total deferred tax assets		90,415			47,103
Valuation allowance for deferred tax assets		(71,368	)		(44,361	)
Deferred tax assets, net of valuation allowance		19,047			2,742
Deferred tax liabilities:
Right-of-use asset		(18,089	)		(2,471	)
Depreciation and amortization		(958	)		(271	)
Net deferred tax assets	$	—		$	—

Summary of Changes in Gross Unrecognized Tax Benefits

The following table summarizes the changes in the Company’s gross unrecognized tax benefits (in thousands):


	December 31,
	2022			2021
Balance at the beginning of the year	$	1,359		$	777
Increases (decreases) related to tax positions taken in prior years		(43	)		(281	)
Increases related to tax positions taken in current year		1,023			863
Balance at the end of the year	$	2,339		$	1,359

Description of Business - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments \| Segment	1
Accumulated deficit	$ 317,933	$ 204,096
Cash, cash equivalents restricted cash and short-term investments	$ 354,900

Basis of Presentation and Significant Accounting Polices - Additional Information (Details)	12 Months Ended	18 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Accounting Policies [Line Items]
Impairment losses on long-lived assets	$ 0
Product revenue		$ 0
Liability regard to loss contingencies	$ 0
Contractual term of options granted	10 years
Employee stock purchase plan look-back period	6 months
Number of operating segments \| Segment	1
Minimum
Accounting Policies [Line Items]
Estimated useful lives of assets	3 years
Maximum
Accounting Policies [Line Items]
Estimated useful lives of assets	5 years
Contractual term of options granted	10 years

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (113,837)	$ (86,075)
Denominator:
Weighted average common shares outstanding	43,635,044	32,901,002
Less: weighted average unvested common stock issued upon early exercise of common stock options	(3,322)	(44,119)
Weighted average shares used to compute net loss per share, basic	43,631,722	32,856,883
Weighted average shares used to compute net loss per share, diluted	43,631,722	32,856,883
Net loss per share, basic	$ (2.61)	$ (2.62)
Net loss per share, diluted	$ (2.61)	$ (2.62)

- Definition

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

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+ Details

Net Loss Per Share - Summarizes the Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,876,511	4,220,867
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,519,275	4,204,686
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	356,728
Unvested Common Stock Upon Early Exercise of Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	508	16,181

Fair Value of Financial Instruments - Summary of Fair Value of Financial Instrument (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Money market funds	$ 36,494	$ 57,018
Total short-term investments	314,649	177,272
Total	351,143	234,290
Commercial Paper
Assets:
Total short-term investments	65,409	21,272
Corporate Debt Securities
Assets:
Total short-term investments	88,681	111,466
U.S. Government Securities
Assets:
Total short-term investments	160,559	44,534
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Money market funds	36,494	57,018
Total	36,494	57,018
Significant Other Observable Inputs (Level 2)
Assets:
Total short-term investments	314,649	177,272
Total	314,649	177,272
Significant Other Observable Inputs (Level 2) \| Commercial Paper
Assets:
Total short-term investments	65,409	21,272
Significant Other Observable Inputs (Level 2) \| Corporate Debt Securities
Assets:
Total short-term investments	88,681	111,466
Significant Other Observable Inputs (Level 2) \| U.S. Government Securities
Assets:
Total short-term investments	$ 160,559	$ 44,534

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Impairments		$ 300
Realized gain or loss on available-for-sale securities		(490)
Subsequent Event
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investments sold	$ 67,600
Realized loss on investments	$ 300
Short-term investments
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Accrued interest receivable		800	$ 1,000
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Money Market Funds
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investments		$ 36,500	$ 57,000

Fair Value of Financial Instruments - Schedule of Short-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	$ 315,328	$ 177,422
Available for sale securities, Unrealized Losses	(762)	(157)
Available for sale securities, Unrealized Gains	83	7
Available for sale securities,Estimated Fair Value	314,649	177,272
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	88,995	111,548
Available for sale securities, Unrealized Losses	(320)	(89)
Available for sale securities, Unrealized Gains	6	7
Available for sale securities,Estimated Fair Value	$ 88,681	$ 111,466
Corporate Debt Securities \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Maturity (in years)	1 year	1 year
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	$ 65,532	$ 21,272
Available for sale securities, Unrealized Losses	(123)
Available for sale securities,Estimated Fair Value	$ 65,409	$ 21,272
Commercial Paper \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Maturity (in years)	1 year	1 year
U.S. Government Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	$ 160,801	$ 44,602
Available for sale securities, Unrealized Losses	(319)	(68)
Available for sale securities, Unrealized Gains	77
Available for sale securities,Estimated Fair Value	$ 160,559	$ 44,534
U.S. Government Securities \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Maturity (in years)	1 year	1 year

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 5,616	$ 4,538
Other current assets	2,929	3,154
Total prepaid expenses and other current assets	$ 8,545	$ 7,692

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Total property and equipment	$ 67,732	$ 16,043
Less accumulated depreciation and amortization	(5,824)	(3,187)
Total property and equipment, net	61,908	12,856
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	4,402	3,462
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	645	544
Research Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	12,900	9,633
Computers and Software
Property Plant And Equipment [Line Items]
Total property and equipment	130	130
Construction in Progress
Property Plant And Equipment [Line Items]
Total property and equipment	$ 49,655	$ 2,274

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization expense	$ 2.6	$ 1.8

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Accrued compensation	$ 6,691	$ 5,453
Accrued research and development costs	3,486	2,280
Accrued property and equipment	5,001	96
Other accrued and current liabilities	858	1,518
Total accrued and other liabilities	$ 16,036	$ 9,347

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Lease, Cost [Abstract]
Operating lease expense	$ 11,220	$ 2,581
Variable lease expense	462	302
Short-term lease expense	45	92
Total lease expense	$ 11,727	$ 2,975

Leases - Schedule of Supplemental Information Related to Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows used for operating leases	$ 6,887	$ 2,239

Leases - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended						12 Months Ended
	Aug. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	May 31, 2020	May 31, 2018	Dec. 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Weighted-average discount rate							9.80%
Right-of-use assets obtained in exchange for operating lease liabilities resulting from new leases							$ 59,500
Right-of-use assets obtained in exchange for operating lease liabilities resulting from modifications of existing leases							18,700
Lessee, operating lease, term of contract			12 years
Cash received for tenant improvement allowances to be repaid			$ 4,400
Lease liabilities							82,934
Right-of-use assets							$ 45,749	$ 11,678
Maximum
Lessee Lease Description [Line Items]
Tenant improvement allowances yet to receive			$ 25,200
Letter of Credit
Lessee Lease Description [Line Items]
Security deposit								$ 1,600
Third amendment
Lessee Lease Description [Line Items]
Operating lease, description							The lease amendment for this additional space commenced in April 2021 and expires in March 2024.
Lease expiration month and year				2024-03
Initial Lease Agreement
Lessee Lease Description [Line Items]
Operating lease, existence of option to extend		true			true
Lease term					8 years
Lease expiration year		2029			2029
Lessee option to extend description		The lease amendment of this additional space commenced in April 2022 and expires in January 2029. The lease amendment also includes this additional space in the Company’s option to extend the amended Initial Lease Agreement for an additional seven-year term.					The lease amendment also includes an extension of the lease term for the existing office and laboratory space beginning on May 1, 2020 and expiring in January 2029. The amendment to the Initial Lease Agreement also includes an option to extend the lease for an additional seven-year term.
Second Amendment Of Additional Lease Agreement
Lessee Lease Description [Line Items]
Tenant improvement allowances yet to receive	$ 25,200
Additional tenant improvement allowances	$ 15,000
Corporate Office and Laboratory Space
Lessee Lease Description [Line Items]
Weighted-average remaining lease term							10 years 9 months 18 days
Lease expiration year						2025
Corporate Office and Laboratory Space \| Initial Lease Agreement
Lessee Lease Description [Line Items]
Renewal term					7 years
Operating lease, existence of option to extend						true
Lessee option to extend description							In April 2019, the Company executed the first amendment to the Initial Lease Agreement for additional corporate space, laboratory space and manufacturing capabilities and an extension to the lease term through April 2026.

Leases - Schedule of Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
2023	$ 11,206
2024	12,671
2025	13,033
2026	13,467
2027	13,917
2028 and thereafter	87,290
Total undiscounted future minimum lease payments	151,584
Less imputed interest	(60,813)
Less tenant improvement receivable	(7,837)
Total operating lease liabilities	82,934
Operating lease liabilities:
Current	4,249	$ 2,484
Non-current	78,685	$ 9,975
Total lease liability	$ 82,934

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Liabilities recorded for agreements	$ 0	$ 0
Agreement with Financial Institution
Loss Contingencies [Line Items]
Letters of credit outstanding amount	$ 2,700,000
Agreement with Financial Institution \| Maximum
Loss Contingencies [Line Items]
Letter of credit notice period by financial institution before annual expiration date	60 days
Agreement with Financial Institution \| Minimum
Loss Contingencies [Line Items]
Letter of credit notice period by financial institution before annual expiration date	30 days

Collaboration and License Agreements - Additional Information (Details)			1 Months Ended		12 Months Ended
	Oct. 26, 2021 USD ($)	May 05, 2021 CrisprCas9	Aug. 31, 2016 SGD ($) shares	Aug. 31, 2016 USD ($) shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development costs					$ 90,897,000	$ 63,412,000
Research Collaboration Agreement \| Development and Regulatory Approval Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reduction of research and development expense resulting from partial reimbursement					$ 4,200,000	2,300,000
Potential future payments					totaling less than mid-twenty million dollars
Amount paid under the agreement					$ 0
Amounts owed under the agreement					0
Receivable under research cost sharing provision					1,300,000
MaxCyte License Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments	$ 10,000,000
Net sales milestone payments	61,900,000
Annual research license fees and Commercialization license fees	100,000
MaxCyte License Agreement \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments	13,000,000
Net sales milestone payments	116,800,000
Annual research license fees and Commercialization license fees	$ 300,000
NK Cell Products \| Research Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of non-exclusive rights to gene editing targets licenses received \| CrisprCas9		3
NK Cell Products \| Research Collaboration Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of non-exclusive rights to gene editing targets \| CrisprCas9		2
NUS and St. Jude \| License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment			$ 42,750	$ 31,800
Upfront payment, shares issued \| shares			250,000	250,000
Fair value of common stock issued				$ 2,500
Annual license maintenance fee			$ 25,000
Potential milestone payments			$ 5,000,000
Percentage of licensors royalties			2.50%	2.50%
NUS and St. Jude \| License Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of sublicensing income			7.50%	7.50%
NUS and St. Jude \| License Agreement \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of sublicensing income			20.00%	20.00%
License agreement term			120 months	120 months
NUS and St. Jude \| License Maintenance Fees \| License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development costs					$ 37,000	$ 37,000
NUS and St. Jude \| After Year Two of the Agreement \| License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Annual license maintenance fee			$ 50,000

Employee Benefits - Additional Information (Details) - 401 (K) Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, description	On January 1, 2018, the Company adopted a defined contribution 401(k) plan that is available to eligible employees.
Employer contribution, percent	3.00%
Expense contribution plan	$ 0.8	$ 0.6

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Apr. 28, 2022	Aug. 12, 2021	Dec. 31, 2022	Dec. 31, 2021	Jul. 14, 2020
Class Of Stock [Line Items]
Common stock, shares authorized			100,000,000	100,000,000	100,000,000
Common stock, par value			$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized			54,350,179	54,350,179	54,350,179
Preferred stock, par value			$ 0.0001	$ 0.0001	$ 0.0001
Maximum
Class Of Stock [Line Items]
Issuance and sale of equity		$ 500.0
Proceeds from Issuance Initial Public Offering		$ 150.0
Common Stock
Class Of Stock [Line Items]
Common stock shares issued and sold			113,213
Common Stock \| IPO
Class Of Stock [Line Items]
Common stock shares issued and sold	15,333,334
Stock public offering price	$ 15.00
Proceeds from Issuance Initial Public Offering	$ 215.3
Common Stock \| Underwriters Option to Purchase Additional Shares
Class Of Stock [Line Items]
Common stock shares issued and sold	2,000,000
Common Stock \| Follow On Offering of Stock
Class Of Stock [Line Items]
Net proceeds from offering			$ 1.6

Share-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate cash proceeds	$ 445,000
Number of common stock available for issuance	8,541,875
Unrecognized compensation cost	$ 34,200,000
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	2 years 6 months
Contractual term of options granted	10 years
Dividends issued for options	$ 0
Dividends expected to be issued over life of options	$ 0
Estimated dividend yield	0.00%
Restricted Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to repurchase	508	16,181
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 3,700
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	3 years 2 months 12 days
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	61,754	0
Number of common stock authorized for issuance	952,524
Aggregate cash proceeds	$ 400
Number of common stock available for issuance	890,770
Maximum percentage of employee compensation eligible for plan	15.00%
Offering period	6 months
Commons stock purchase price as percentage of fair value	85.00%
Unrecognized compensation cost	$ 100
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	4 months 24 days
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	1,344,048
2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock authorized for issuance	5,945,002
Increase in share limit as percentage of outstanding shares of common stock on last trading day in prior year	5.00%
Number of common stock available for issuance	1,775,102

Share-Based Compensation - Summary of Stock Option Activity (Details) - 2020 Plan and 2015 Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, outstanding beginning balance	4,204,686
Number of shares, granted	2,327,820
Number of shares, exercised	(383,120)
Number of shares, forfeited	(630,111)
Number of shares, outstanding ending balance	5,519,275	4,204,686
Number of shares, exercisable	2,337,753
Number of shares, vested and expected to vest	5,519,275
Weighted-average exercise price, outstanding beginning balance	$ 19.19
Weighted-average exercise price, granted	12.61
Weighted-average exercise price, exercised	3.62
Weighted-average exercise price, forfeited	21.99
Weighted-average exercise price, outstanding ending balance	17.17	$ 19.19
Weighted-average exercise price, exercisable	17.49
Weighted-average exercise price, vested and expected to vest	$ 17.17
Weighted-average remaining contractual term (in years), outstanding balance	8 years 1 month 6 days	8 years 2 months 12 days
Weighted-average remaining contractual term (in years), exercisable	7 years 4 months 24 days
Weighted-average remaining contractual term (in years), vested and expected to vest	8 years 1 month 6 days
Aggregate intrinsic value, outstanding balance	$ 2,915
Aggregate intrinsic value, exercisable	1,957
Aggregate intrinsic value, vested and expected to vest	$ 2,915

Share-Based Compensation - Summary of Additional Information Related to Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Weighted-average grant-date fair value of stock option grants per share	$ 8.60	$ 30.87
Intrinsic value of options exercised	$ 4,268	$ 9,991

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Unit Activity	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, outstanding beginning balance \| shares	0
Number of shares, granted \| shares	389,388
Number of shares, forfeited \| shares	(32,660)
Number of shares, outstanding ending balance \| shares	356,728
Weighted-average grant date fair value per share, outstanding beginning balance \| $ / shares	$ 0
Weighted-average grant date fair value per share, granted \| $ / shares	12.62
Weighted-average grant date fair value per share, forfeited \| $ / shares	12.15
Weighted-average grant date fair value per share, outstanding ending balance \| $ / shares	$ 12.66
Weighted-average remaining contractual term (in years), outstanding ending balance	1 year 8 months 12 days

Share-Based Compensation - Summary of Common Stock Reserved for Future Issuance (Details)	Dec. 31, 2022 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	8,541,875
Reserved for Future ESPP Issuances
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	890,770
Reserved for Future Equity Award Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	1,775,102
Common Stock Options And Restricted Stock Units Granted And Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	5,876,003

Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 16,856	$ 14,461
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	7,326	6,719
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 9,530	$ 7,742

Share-Based Compensation - Schedule of Fair Value of Stock Options Estimated on Date of Grant Using Black-Scholes Option Pricing Model (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%
Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.60%	0.60%
Risk-free interest rate, maximum	4.20%	1.40%
Expected volatility, minimum	75.70%	77.30%
Expected volatility, maximum	78.90%	79.90%
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.60%
Risk-free interest rate, maximum	4.70%
Expected volatility, minimum	63.80%
Expected volatility, maximum	151.90%
Expected term (in years)	6 months
Minimum \| Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock fair value	$ 5.99	$ 15.35
Expected term (in years)	5 years 6 months	5 years 6 months
Maximum \| Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock fair value	$ 18.44	$ 54.89
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019	Dec. 31, 2020
Income Taxes [Line Items]
Provision or benefit for income taxes	$ 0	$ 0
Increase in valuation allowance of net deferred tax assets	27,000,000.0	20,700,000
Gross unrecognized tax benefits	2,339,000	1,359,000		$ 777,000
Unrecognized tax benefits, penalties and interest expense	0	$ 0
Net Operating Loss and Tax Credit Carryforwards to Offset \| Minimum
Income Taxes [Line Items]
Changes in ownership by stockholders holding percentage			5.00%
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	153,300,000
Federal \| Research and Development Credit Carry Forwards
Income Taxes [Line Items]
Tax credit carryforwards	$ 9,900,000
Tax credit carryforwards, expire	2035
Federal \| 2035
Income Taxes [Line Items]
Net operating loss carryforwards	$ 200,000
Net operating loss carryforwards, expire	2035
Federal \| 2036
Income Taxes [Line Items]
Net operating loss carryforwards	$ 3,000,000.0
Net operating loss carryforwards, expire	2036
Federal \| Carry Forward Indefinitely
Income Taxes [Line Items]
Net operating loss carryforwards	$ 150,100,000
California State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 65,100,000
Net operating loss carryforwards, expire	2036
California State \| Research and Development Credit Carry Forwards
Income Taxes [Line Items]
Tax credit carryforwards	$ 5,600,000

Income Taxes - Reconciliation on Income Taxes Amount Computed by Applying Statutory Federal Income Tax Rate to Net Loss (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax benefit at statutory rates	$ (23,906,000)	$ (18,076,000)
State income tax, net of federal benefit	(1,566,000)	(1,005,000)
Permanent items	1,891,000	592,000
Research and development credits	(3,426,000)	(1,661,000)
Other	(0)	(515,000)
Change in valuation allowance	27,007,000	20,665,000
Income tax expense	$ 0	$ 0

- Definition

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

+ References + Details

Income Taxes - Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carry forwards	$ 36,732	$ 33,767
Depreciation and amortization	316	268
Research and development credits	11,999	6,984
Share-based compensation	3,552	2,245
Accrued expenses	1,367	1,189
Lease liability	19,062	2,616
Other, net	35	34
Section 174 Capitalized R&D	17,352	0
Total deferred tax assets	90,415	47,103
Valuation allowance for deferred tax assets	(71,368)	(44,361)
Deferred tax assets, net of valuation allowance	19,047	2,742
Deferred tax liabilities:
Right-of-use asset	(18,089)	(2,471)
Depreciation and amortization	(958)	(271)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Summary of Changes in Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Balance at the beginning of the year	$ 1,359	$ 777
Increases (decreases) related to tax positions taken in prior years	(43)	(281)
Increases related to tax positions taken in current year	1,023	863
Balance at the end of the year	$ 2,339	$ 1,359

Subsequent Events - Additional Information (Details) $ in Millions	Mar. 10, 2023 USD ($)
Subsequent Event \| Initial Lease Agreement and Additional Lease Agreement
Subsequent Event [Line Items]
Amount held as collateral for letters of credit issued to landlord	$ 2.7