Nkarta (NKTX) 10-Q 11 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 08, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
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		48,934,928
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001787400

CONDENSED BALANCE SHEETS (Unaud

CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 53,666	$ 37,494
Short-term investments	269,675	314,649
Prepaid expenses and other current assets	8,847	8,545
Total current assets	332,188	360,688
Long-term investments	6,016
Restricted cash	2,743	2,743
Property and equipment, net	69,777	61,908
Operating lease right-of-use assets	45,575	45,749
Other long-term assets	1,870	1,850
Total assets	458,169	472,938
Current liabilities
Accounts payable	5,411	1,761
Operating lease liabilities, current portion	5,752	4,249
Accrued and other current liabilities	14,818	16,036
Total current liabilities	25,981	22,046
Operating lease liabilities, net of current portion	85,542	78,685
Total liabilities	111,523	100,731
Commitments and contingencies (Note 7)
Stockholders’ equity
Common stock	5	5
Additional paid-in capital	695,563	690,814
Accumulated other comprehensive loss	(174)	(679)
Accumulated deficit	(348,748)	(317,933)
Total stockholders’ equity	346,646	372,207
Total liabilities and stockholders’ equity	$ 458,169	$ 472,938

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating expenses
Research and development	$ 26,135	$ 19,568
General and administrative	8,178	6,530
Total operating expenses	34,313	26,098
Loss from operations	(34,313)	(26,098)
Other income (expense), net:
Interest income	3,465	112
Other income (expense), net	33	(1)
Total other income, net	3,498	111
Net loss	(30,815)	(25,987)
Other comprehensive loss:
Net unrealized gain (loss) on investments	505	(456)
Comprehensive loss	$ (30,310)	$ (26,443)
Net loss per share, basic	$ (0.63)	$ (0.79)
Net loss per share, diluted	$ (0.63)	$ (0.79)
Weighted average shares used to compute net loss per share, basic	48,921,326	32,992,582
Weighted average shares used to compute net loss per share, diluted	48,921,326	32,992,582

CONDENSED STATEMENTS OF STOCKHO

CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 250,967	$ 3	$ 455,210	$ (150)	$ (204,096)
Beginning Balance, Shares at Dec. 31, 2021		32,971,107
Vesting of shares of common stock subject to repurchase	6		6
Vesting of shares of common stock subject to repurchase, Shares		10,924
Issuance of common stock upon exercise of stock option,	79		79
Issuance of common stock upon exercise of stock option,, Shares		21,067
Share-based compensation expense	4,097		4,097
Unrealized gain (loss) on short-term investments	(456)			(456)
Net loss	(25,987)				(25,987)
Ending Balance at Mar. 31, 2022	228,706	$ 3	459,392	(606)	(230,083)
Ending Balance, Shares at Mar. 31, 2022		33,003,098
Beginning Balance at Dec. 31, 2022	372,207	$ 5	690,814	(679)	(317,933)
Beginning Balance, Shares at Dec. 31, 2022		48,877,806
Vesting of shares of common stock subject to repurchase	2		2
Vesting of shares of common stock subject to repurchase, Shares		395
Issuance of common stock upon exercise of stock option,	1		1
Issuance of common stock upon exercise of stock option,, Shares		253
Issuance of common stock upon vesting of restricted stock units, Shares		50,469
Share-based compensation expense	4,746		4,746
Unrealized gain (loss) on short-term investments	505			505
Net loss	(30,815)				(30,815)
Ending Balance at Mar. 31, 2023	$ 346,646	$ 5	$ 695,563	$ (174)	$ (348,748)
Ending Balance, Shares at Mar. 31, 2023		48,928,923

CONDENSED STATEMENT OF CASH FLO

CONDENSED STATEMENT OF CASH FLOWS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities
Net loss	$ (30,815,000)	$ (25,987,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	4,746,000	4,097,000
Depreciation and amortization	797,000	610,000
Accretion and amortization of premiums and discounts on investments, net	(2,253,000)	727,000
Realized gain on investments	(34,000)	0
Non-cash lease expense	545,000	1,380,000
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(406,000)	1,460,000
Operating lease liabilities	7,992,000	1,614,000
Accounts payable and accrued and other liabilities	(1,330,000)	(2,159,000)
Net cash used in operating activities	(20,758,000)	(18,258,000)
Cash flows from investing activities
Purchases of property and equipment	(4,823,000)	(1,770,000)
Purchases of investments	(84,288,000)	(28,472,000)
Maturities of investments	126,040,000	29,216,000
Net cash provided by (used in) investing activities	36,929,000	(1,026,000)
Cash flows from financing activities
Proceeds from stock option exercises	1,000	79,000
Net cash provided by financing activities	1,000	79,000
Net increase (decrease) in cash and cash equivalents	16,172,000	(19,205,000)
Cash, cash equivalents, and restricted cash beginning of period	40,237,000	62,914,000
Cash, cash equivalents, and restricted cash end of period	56,409,000	43,709,000
Reconciliation of cash, cash equivalents and restricted cash to the balance sheet:
Cash and cash equivalents	53,666,000	41,611,000
Restricted cash	2,743,000	2,098,000
Total cash, cash equivalents and restricted cash	56,409,000	43,709,000
Supplemental disclosures of non-cash investing activities:
Acquisitions of property and equipment in accounts payable	$ 3,761,000	$ 37,000

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and 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 unaudited condensed financial statements have been prepared assuming that the Company will continue as a going concern. However, 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 March 31, 2023, the Company had an accumulated deficit of $ 348.7 million and cash, cash equivalents, restricted cash and investments of $ 332.1 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 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. On March 17, 2023, the Company filed a Registration Statement on Form S-3, as amended by the Form S-3/A filed on April 24, 2023 (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 $ 350.0 million in aggregate offering price of shares of the Company’s common stock, shares of the Company’s preferred stock, debt securities, warrants, rights and/or units, including up to $ 120.0 million in aggregate offering price of shares of the Company’s common stock, shares of the Company’s preferred stock, debt securities, warrants, rights and/or units registered on the Company’s Registration Statement on Form S-3 declared effective by the Securities and Exchange Commission (the "SEC") on September 2, 2021 (the "Prior Registration Statement") that have not yet been sold. The Shelf Registration Statement was declared effective by the SEC on May 5, 2023. On August 12, 2021, the Company entered into a sales agreement with Cowen and Company, LLC, a sales agent, to provide for the offering, issuance and sale of up to an aggregate of $ 150.0 million of the Company’s common stock through an “at-the-market” equity offering program (the "ATM Offering Program") pursuant to the Prior Registration Statement and subject to the limitations thereof. For the three months ended March 31, 2023, no sales of the Company’s common stock were made pursuant to the ATM Offering Program.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed financial statements as of March 31, 2023 and for the three-months ended March 31, 2023 and 2022 have been prepared in accordance with U.S. generally accepted accounting principle ("U.S. GAAP") for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act, as amended. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited condensed financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows for the periods presented. The results for the three months ended March 31, 2023 are not necessarily indicative of the results expected for the full year or any subsequent interim period. The condensed balance sheet at December 31, 2022 has been derived from the audited financial statements at that date but does not include all disclosures required by U.S. GAAP for complete financial statements. Because all of the disclosures required by U.S. GAAP for complete financial statements are not included herein, these unaudited condensed financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2022, contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 filed by the Company with the SEC on March 16, 2023. COVID-19 Pandemic The COVID-19 pandemic has caused disruptions in the global economy and has affected and may 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 or the three months ended March 31, 2023. 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, leases, 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. 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 convertible preferred stock prior to the conversion of such shares to common stock, unvested common stock, and outstanding stock options under the Company’s equity incentive plans, 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.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2023
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): Three Months Ended 2023 2022 Numerator: Net loss $ ( 30,815 ) $ ( 25,987 ) Denominator: Weighted average common shares outstanding 48,921,535 33,000,238 Less: weighted average unvested common stock ( 209 ) ( 7,656 ) Weighted average shares used to compute net loss 48,921,326 32,992,582 Net loss per share, basic and diluted $ ( 0.63 ) $ ( 0.79 ) 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: As of March 31, 2023 2022 Common stock options 6,820,096 5,070,367 Restricted stock units 799,930 229,418 Unvested common stock upon early exercise of common stock 113 5,257 7,620,139 5,305,042

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2023
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 March 31, Quoted Prices Significant Significant Assets: Cash equivalents: Money market funds $ 52,666 $ 52,666 $ — $ — Short-term investments: Corporate debt securities $ 50,351 $ — $ 50,351 $ — Commercial paper 20,298 — 20,298 — U.S. Government securities 199,026 — 199,026 — Total short-term investments 269,675 — 269,675 — Long-term investments: U.S. Government securities $ 6,016 $ — $ 6,016 $ — Total $ 328,357 $ 52,666 $ 275,691 $ — Fair Value Measurements Using December 31, Quoted Prices Significant Significant 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 $ — Cash Equivalents and Investments Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term and long-term investments. Cash equivalents consisted of money market funds and short-term and long-term investments consisted of commercial paper, government securities and corporate bonds. 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 $ 52.7 million and $ 36.5 million as of March 31, 2023 and December 31, 2022, respectively, were classified as Level 1 instruments and were included in cash and cash equivalents. Investments in marketable securities 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 marketable securities of $ 275.7 million and $ 314.6 million as of March 31, 2023 and December 31, 2022, respectively, were classified as Level 2 instruments. As of March 31, 2023, marketable securities of $ 269.7 million were included in short-term investments and marketable securities of $ 6.0 million were included in long-term investments. As of December 31, 2022, marketable securities of $ 314.6 million were included in short-term investments. Accrued interest receivable related to investments was $ 0.6 million and $ 0.8 million as of March 31, 2023 and December 31, 2022, respectively, and included as part of prepaid expenses and other current assets in the condensed balance sheets. The following tables summarize the Company’s investments accounted for as available-for-sale securities as of March 31, 2023 and December 31, 2022 (in thousands): March 31, 2023 Maturity Amortized Unrealized Unrealized Estimated Corporate debt securities 1 year or less $ 50,478 $ ( 127 ) $ 50,351 Commercial paper 1 year or less 20,341 ( 43 ) — 20,298 U.S. Government securities 1 year or less 199,057 ( 166 ) 135 199,026 U.S. Government securities Greater than 1 year 5,989 — 27 6,016 Total $ 275,865 $ ( 336 ) $ 162 $ 275,691 December 31, 2022 Maturity Amortized Unrealized Unrealized Estimated 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 The Company has classified its investment securities as current and non-current assets on the condensed balance sheets based on each security's contractual maturity date, and all investment securities are accounted for as available-for-sale because these investment securities are considered available for use in current operations. 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 March 31, 2023 and December 31, 2022 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 March 31, 2023 and December 31, 2022. 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. Unrealized gains and losses are included in accumulated other comprehensive loss. During the three months ended March 31, 2023, there were immaterial realized gains recognized on available-for-sale securities sold in the period. There was no realized gain or loss on available-for-sale securities for the three months ended March 31, 2022. The Company uses the specific identification method to determine the cost basis of investments sold.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2023
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): March 31, December 31, Prepaid expenses $ 5,475 $ 5,616 Other current assets 3,372 2,929 Total prepaid expenses and other current assets $ 8,847 $ 8,545 Property and Equipment, Net Property and equipment, net is comprised of the following (in thousands): March 31, December 31, Leasehold improvements $ 4,402 $ 4,402 Furniture and fixtures 645 645 Research equipment 13,900 12,900 Computers and software 404 130 Construction in progress 57,047 49,655 Total property and equipment, gross 76,398 67,732 Less accumulated depreciation and amortization ( 6,621 ) ( 5,824 ) Total property and equipment, net $ 69,777 $ 61,908 Depreciation and amortization expense was $ 0.8 million and $ 0.6 million for the three months ended March 31, 2023 and 2022, respectively. Accrued and Other Current Liabilities Accrued other current liabilities are comprised of the following (in thousands): March 31, December 31, Accrued compensation $ 3,768 $ 6,691 Accrued research and development costs 4,856 3,486 Accrued property and equipment 5,142 5,001 Other accrued and current liabilities 1,052 858 Total accrued and other liabilities $ 14,818 $ 16,036

Leases

Leases	3 Months Ended
	Mar. 31, 2023
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. Rent expense, which is recognized on a straight-line basis over the term of each lease, was $ 2.7 million and $ 2.6 million for the three months ended March 31, 2023 and 2022, respectively. The total cash received for operating leases included in the operating cash flows was $ 5.8 million and $ 0.3 million, inclusive of $ 7.8 million and $ 0.9 million of cash received related to tenant improvement allowance reimbursement less $ 2.0 million and $ 0.6 million of rent payments, for the three months ended March 31, 2023 and 2022, respectively. The weighted-average remaining lease term was 10.5 years for the corporate office, laboratory space leases, and additional facility as of March 31, 2023. The weighted-average discount rate was 9.7 % as of March 31, 2023. 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 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 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 lease of additional space in the same building . The lease for additional office and laboratory space 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 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 ba se 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 ("SVB") 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. In March 2023, the Company 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. In April 2023, the Company replaced the $ 2.7 million in letters of credit issued by SVB with letters of credit in the same amount from a different financial institution, and the Company entered into a third amendment to the Additional Lease Agreement. The lease amendment clarifies the form of letter of credit. The other terms of the Additional Lease Agreement, as amended, remain unchanged. Maturities of operating lease liabilities under existing operating leases as of March 31, 2023 were as follows (in thousands): Year ending December 31, Amount 2023 (remaining nine months) $ 9,404 2024 12,823 2025 13,033 2026 13,467 2027 13,917 2028 and thereafter 87,290 Total undiscounted future minimum lease payments 149,934 Less imputed interest ( 58,640 ) Total operating lease liabilities $ 91,294 Operating lease liabilities: Current 5,752 Non-current 85,542 Total lease liability $ 91,294

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments & 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 March 31, 2023 and December 31, 2022. Letters of Credit As of March 31, 2023, the Company had $ 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. The letters of credit are presented as restricted cash in the condensed balance sheet. Contingencies The Company, from time to time, may be involved in litigation arising in the ordinary course of business . The Company assesses its potential liability in such situations by analyzing potential outcomes, assuming various litigation, regulatory and settlement strategies. If the Company determines a loss is probable and its amount can be reasonably estimated, the Company accrues an amount equal to the estimated loss. No losses and no provision for a loss contingency have been recorded to date. Purchase Commitments The Company enters into contracts in the normal course of business for clinical trials, preclinical studies, manufacturing and other services and products for operating purposes. These contracts generally provide for termination following a certain period after notice and therefore the Company believes that non-cancelable obligations under these agreements are not material.

CRISPR Collaboration Agreement

CRISPR Collaboration Agreement	3 Months Ended
	Mar. 31, 2023
Collaboration Agreement [Abstract]
CRISPR Collaboration Agreement	8. CRISPR Collaboration Agreement On May 5, 2021, the Company entered into a research collaboration agreement (as amended, the "CRISPR Agreement") with CRISPR Therapeutics AG ("CRISPR") to co-develop and co-commercialize an allogeneic, off-the-shelf chimeric antigen receptor-natural killer ("CAR NK") product candidate targeting the CD70 tumor antigen ("NKX070") and an allogeneic, off-the-shelf product candidate that comprises both engineered NK cells and engineered T cells ("NK+T"). In May 2022, the CRISPR Agreement was amended to revise the transfer of materials and nomination provisions. On March 8, 2023, the CRISPR Agreement was further amended to permit Nkarta's advancement of CRISPR-licensed product candidates targeting a specified tumor antigen (the "Specified TA") and incorporate associated development and regulatory approval milestones and sales based royalties. In addition, the Company has received licenses from CRISPR for four CRISPR-Cas9 gene editing targets and will receive a license from CRISPR for up to one 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 $ 0.9 million and $ 1.0 million for the three months ended March 31, 2023, respectively. As of March 31, 2023, the Company had a $ 2.3 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"), other than those targeting the Specified TA, 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 , as well as tiered royalties up to the mid-single digits on net product sales of such product candidate. For each CRISPR-Licensed Product Candidate targeting the Specified TA, 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 high-forty million dollars , as well as tiered royalties up to the mid-single digits on net product sales of such product candidate. As of March 31, 2023, the Company has no t paid any amounts no r are any amounts owed by the Company under the CRISPR Agreement, and no milestones have been achieved.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	9. Share-Based Compensation Equity 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 Company’s initial public offering in July 2020 ("IPO"). Upon the effectiveness of the 2020 Plan, no further grants may be made under the Company’s 2015 Equity Incentive Plan (the "2015 Plan"). 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 March 31, 2023, a total of 8,388,917 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, through that date). 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 2,424,272 shares were available for issuance under the 2020 Plan as of March 31, 2023. The following table summarizes the option activity under the 2020 Plan and 2015 Plan during the three months ended March 31, 2023: Number of shares Weighted- Weighted- Outstanding at December 31, 2022 5,519,275 $ 17.17 8.1 Granted 1,363,428 5.54 Exercised ( 253 ) 3.89 Forfeited ( 62,354 ) 14.52 Outstanding at March 31, 2023 6,820,096 $ 14.87 8.3 Exercisable at March 31, 2023 2,697,880 $ 17.16 7.3 Vested and expected to vest at March 31, 2023 6,820,096 $ 14.87 8.3 The weighted-average grant date fair value of stock option grants was $ 4.22 per share for the three months ended March 31, 2023. The following table summarizes the restricted stock unit activity under the 2020 Plan during the three months ended March 31, 2023: Number of shares Weighted-average Outstanding at December 31, 2022 356,728 $ 12.66 Granted 503,639 5.57 Vested ( 50,469 ) 12.14 Forfeited ( 9,968 ) 9.31 Outstanding at March 31, 2023 799,930 $ 8.27 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 1,441,307 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. The six-month offering periods extend from June to November and December to May. As of March 31, 2023, 61,754 shares had been issued under the ESPP, and 1,379,553 shares remained available for issuance under the ESPP (after giving effect to share purchases under the ESPP through and including the offering period on November 30, 2022). As of March 31, 2023, employee contributions to the ESPP were $ 0.5 million and included as part of accrued and other current liabilities in the condensed balance sheets. Share-Based Compensation Expense Share-based compensation expense for the three ended March 31, 2023 and 2022 was as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 2,082 $ 1,855 General and administrative 2,664 2,242 Total share-based compensation $ 4,746 $ 4,097 The total unrecognized compensation cost related to unvested stock options was $ 35.2 million, which is expected to be recognized over a weighted-average remaining service period of 2.8 years as of March 31, 2023. The total unrecognized compensation cost related to unvested restricted stock units was $ 6.0 million, which is expected to be recognized over a weighted-average remaining service period of 3.5 years as of March 31, 2023. As of March 31, 2023, 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 0.2 years.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes There was no provision for income taxes recorded during the three months ended March 31, 2023 and 2022. The Company’s deferred tax assets continue to be fully offset by a valuation allowance .

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements as of March 31, 2023 and for the three-months ended March 31, 2023 and 2022 have been prepared in accordance with U.S. generally accepted accounting principle ("U.S. GAAP") for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act, as amended. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited condensed financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows for the periods presented. The results for the three months ended March 31, 2023 are not necessarily indicative of the results expected for the full year or any subsequent interim period. The condensed balance sheet at December 31, 2022 has been derived from the audited financial statements at that date but does not include all disclosures required by U.S. GAAP for complete financial statements. Because all of the disclosures required by U.S. GAAP for complete financial statements are not included herein, these unaudited condensed financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2022, contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 filed by the Company with the SEC on March 16, 2023.
COVID-19 Pandemic	COVID-19 Pandemic The COVID-19 pandemic has caused disruptions in the global economy and has affected and may 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 or the three months ended March 31, 2023. 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, leases, 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.
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 convertible preferred stock prior to the conversion of such shares to common stock, unvested common stock, and outstanding stock options under the Company’s equity incentive plans, 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.

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2023
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): Three Months Ended 2023 2022 Numerator: Net loss $ ( 30,815 ) $ ( 25,987 ) Denominator: Weighted average common shares outstanding 48,921,535 33,000,238 Less: weighted average unvested common stock ( 209 ) ( 7,656 ) Weighted average shares used to compute net loss 48,921,326 32,992,582 Net loss per share, basic and diluted $ ( 0.63 ) $ ( 0.79 )
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: As of March 31, 2023 2022 Common stock options 6,820,096 5,070,367 Restricted stock units 799,930 229,418 Unvested common stock upon early exercise of common stock 113 5,257 7,620,139 5,305,042

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2023
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 March 31, Quoted Prices Significant Significant Assets: Cash equivalents: Money market funds $ 52,666 $ 52,666 $ — $ — Short-term investments: Corporate debt securities $ 50,351 $ — $ 50,351 $ — Commercial paper 20,298 — 20,298 — U.S. Government securities 199,026 — 199,026 — Total short-term investments 269,675 — 269,675 — Long-term investments: U.S. Government securities $ 6,016 $ — $ 6,016 $ — Total $ 328,357 $ 52,666 $ 275,691 $ — Fair Value Measurements Using December 31, Quoted Prices Significant Significant 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 $ —
Short-term investments
Schedule of Short-term Investments	The following tables summarize the Company’s investments accounted for as available-for-sale securities as of March 31, 2023 and December 31, 2022 (in thousands): March 31, 2023 Maturity Amortized Unrealized Unrealized Estimated Corporate debt securities 1 year or less $ 50,478 $ ( 127 ) $ 50,351 Commercial paper 1 year or less 20,341 ( 43 ) — 20,298 U.S. Government securities 1 year or less 199,057 ( 166 ) 135 199,026 U.S. Government securities Greater than 1 year 5,989 — 27 6,016 Total $ 275,865 $ ( 336 ) $ 162 $ 275,691 December 31, 2022 Maturity Amortized Unrealized Unrealized Estimated 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

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2023
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): March 31, December 31, Prepaid expenses $ 5,475 $ 5,616 Other current assets 3,372 2,929 Total prepaid expenses and other current assets $ 8,847 $ 8,545
Schedule of Property and Equipment, Net	Property and equipment, net is comprised of the following (in thousands): March 31, December 31, Leasehold improvements $ 4,402 $ 4,402 Furniture and fixtures 645 645 Research equipment 13,900 12,900 Computers and software 404 130 Construction in progress 57,047 49,655 Total property and equipment, gross 76,398 67,732 Less accumulated depreciation and amortization ( 6,621 ) ( 5,824 ) Total property and equipment, net $ 69,777 $ 61,908
Schedule of Accrued Other Current Liabilities	Accrued other current liabilities are comprised of the following (in thousands): March 31, December 31, Accrued compensation $ 3,768 $ 6,691 Accrued research and development costs 4,856 3,486 Accrued property and equipment 5,142 5,001 Other accrued and current liabilities 1,052 858 Total accrued and other liabilities $ 14,818 $ 16,036

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Schedule of Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities under existing operating leases as of March 31, 2023 were as follows (in thousands): Year ending December 31, Amount 2023 (remaining nine months) $ 9,404 2024 12,823 2025 13,033 2026 13,467 2027 13,917 2028 and thereafter 87,290 Total undiscounted future minimum lease payments 149,934 Less imputed interest ( 58,640 ) Total operating lease liabilities $ 91,294 Operating lease liabilities: Current 5,752 Non-current 85,542 Total lease liability $ 91,294

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes the option activity under the 2020 Plan and 2015 Plan during the three months ended March 31, 2023: Number of shares Weighted- Weighted- Outstanding at December 31, 2022 5,519,275 $ 17.17 8.1 Granted 1,363,428 5.54 Exercised ( 253 ) 3.89 Forfeited ( 62,354 ) 14.52 Outstanding at March 31, 2023 6,820,096 $ 14.87 8.3 Exercisable at March 31, 2023 2,697,880 $ 17.16 7.3 Vested and expected to vest at March 31, 2023 6,820,096 $ 14.87 8.3
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock unit activity under the 2020 Plan during the three months ended March 31, 2023: Number of shares Weighted-average Outstanding at December 31, 2022 356,728 $ 12.66 Granted 503,639 5.57 Vested ( 50,469 ) 12.14 Forfeited ( 9,968 ) 9.31 Outstanding at March 31, 2023 799,930 $ 8.27
Summary of Share-based Compensation Expense	Share-based compensation expense for the three ended March 31, 2023 and 2022 was as follows (in thousands): Three Months Ended 2023 2022 Research and development $ 2,082 $ 1,855 General and administrative 2,664 2,242 Total share-based compensation $ 4,746 $ 4,097

Organization and Description _2

Organization and Description of Business - Additional Information (Details) $ in Thousands				3 Months Ended
	May 17, 2023 USD ($)	Sep. 02, 2021 USD ($)	Aug. 12, 2021 USD ($)	Mar. 31, 2023 USD ($) Segment shares	Dec. 31, 2022 USD ($)
Class Of Stock [Line Items]
Number of operating segments | Segment				1
Accumulated deficit				$ 348,748	$ 317,933
Cash, cash equivalents restricted cash and short-term investments				$ 332,100
Maximum
Class Of Stock [Line Items]
Proceeds from issuance initial public offering			$ 150,000
IPO | Maximum
Class Of Stock [Line Items]
Aggregate offering price	$ 350,000	$ 120,000
Common Stock
Class Of Stock [Line Items]
Common stock shares issued and sold | shares				0

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss	$ (30,815)	$ (25,987)
Denominator:
Weighted average common shares outstanding	48,921,535	33,000,238
Less: weighted average unvested common stock issued upon early exercise of common stock options	(209)	(7,656)
Weighted average shares used to compute net loss per share, basic	48,921,326	32,992,582
Weighted average shares used to compute net loss per share, diluted	48,921,326	32,992,582
Net loss per share, basic	$ (0.63)	$ (0.79)
Net loss per share, diluted	$ (0.63)	$ (0.79)

Net Loss Per Share - Summarizes

Net Loss Per Share - Summarizes the Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	7,620,139	5,305,042
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	6,820,096	5,070,367
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	799,930	229,418
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	113	5,257

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary of Fair Value of Financial Instrument (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets:
Money market funds	$ 52,666	$ 36,494
Total short-term investments	269,675	314,649
Long-term investments	6,016
Total	328,357	351,143
Commercial Paper
Assets:
Total short-term investments	20,298	65,409
Corporate Debt Securities
Assets:
Total short-term investments	50,351	88,681
U.S. Government securities
Assets:
Total short-term investments	199,026	160,559
Long-term investments	6,016
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Money market funds	52,666	36,494
Total	52,666	36,494
Significant Other Observable Inputs (Level 2)
Assets:
Total short-term investments	269,675	314,649
Total	275,691	314,649
Significant Other Observable Inputs (Level 2) | Commercial Paper
Assets:
Total short-term investments	20,298	65,409
Significant Other Observable Inputs (Level 2) | Corporate Debt Securities
Assets:
Total short-term investments	50,351	88,681
Significant Other Observable Inputs (Level 2) | U.S. Government securities
Assets:
Total short-term investments	199,026	$ 160,559
Long-term investments	$ 6,016

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Realized gain or loss on available-for-sale securities	$ 34,000	$ 0
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	52,700,000		$ 36,500,000
Significant Other Observable Inputs (Level 2)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Marketable securities	275,700,000		314,600,000
Accrued interest receivable	600,000		800,000
Significant Other Observable Inputs (Level 2) | Short-term investments
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Marketable securities	269,700,000		$ 314,600,000
Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Marketable securities	$ 6,000,000

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Schedule of Short-term Investments Accounted as Available-for-sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	$ 275,865	$ 315,328
Available for sale securities, Unrealized Losses	(336)	(762)
Available for sale securities, Unrealized Gains	162	83
Available for sale securities,Estimated Fair Value	275,691	314,649
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale securities, Amortized Cost	50,478	88,995
Available for sale securities, Unrealized Losses	(127)	(320)
Available for sale securities, Unrealized Gains		6
Available for sale securities,Estimated Fair Value	$ 50,351	$ 88,681
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	$ 20,341	$ 65,532
Available for sale securities, Unrealized Losses	(43)	(123)
Available for sale securities,Estimated Fair Value	$ 20,298	$ 65,409
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	$ 199,057	$ 160,801
Available for sale securities, Unrealized Losses	(166)	(319)
Available for sale securities, Unrealized Gains	135	77
Available for sale securities,Estimated Fair Value	$ 199,026	$ 160,559
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
U.S. Government securities | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Maturity (in years)	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	$ 5,989
Available for sale securities, Unrealized Gains	27
Available for sale securities,Estimated Fair Value	$ 6,016

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 5,475	$ 5,616
Other current assets	3,372	2,929
Total prepaid expenses and other current assets	$ 8,847	$ 8,545

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 76,398	$ 67,732
Less accumulated depreciation and amortization	(6,621)	(5,824)
Total property and equipment, net	69,777	61,908
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	4,402	4,402
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	645	645
Research Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	13,900	12,900
Computers and Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	404	130
Construction in Progress
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 57,047	$ 49,655

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization expense	$ 0.8	$ 0.6

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Accrued Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued compensation	$ 3,768	$ 6,691
Accrued research and development costs	4,856	3,486
Accrued property and equipment	5,142	5,001
Other accrued and current liabilities	1,052	858
Total accrued and other liabilities	$ 14,818	$ 16,036

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended						3 Months Ended
	Aug. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	May 31, 2020	May 31, 2018	Mar. 31, 2023	Mar. 31, 2022	Apr. 30, 2023
Lessee Lease Description [Line Items]
Rent expense							$ 2.7	$ 2.6
Weighted-average remaining lease term							10 years 6 months
Cash paid for operating leases							$ 2	0.6
Weighted-average discount rate							9.70%
Lessee, operating lease, term of contract			12 years
Cash received for tenant improvement allowances to be repaid			$ 4.4
Cash received for operating leases							$ 5.8	0.3
Cash received related to tenant improvement allowance reimbursement							7.8	$ 0.9
Maximum
Lessee Lease Description [Line Items]
Tenant improvement allowances yet to receive			$ 25.2
Letter of Credit
Lessee Lease Description [Line Items]
Security deposit							$ 1.6
Letter of credit									$ 2.7
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 And Additional Lease Agreement
Lessee Lease Description [Line Items]
Amount held as collateral for letters of credit issued to landlord							$ 2.7
Second Amendment Of Additional Lease Agreement
Lessee Lease Description [Line Items]
Additional tenant improvement allowances	$ 15
Tenant improvement allowances yet to receive	$ 25.2
Initial Lease Agreement
Lessee Lease Description [Line Items]
Lease expiration year		2029			2029
Operating lease, existence of option to extend		true			true
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
Lease term					8 years
Corporate Office and Laboratory Space
Lessee Lease Description [Line Items]
Lease expiration year						2025
Corporate Office and Laboratory Space | Initial Lease Agreement
Lessee Lease Description [Line Items]
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.
Renewal term					7 years

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2023 (remaining nine months)	$ 9,404
2024	12,823
2025	13,033
2026	13,467
2027	13,917
2028 and thereafter	87,290
Total undiscounted future minimum lease payments	149,934
Less imputed interest	(58,640)
Total operating lease liabilities	91,294
Operating lease liabilities:
Operating lease liabilities, current portion	5,752	$ 4,249
Operating lease liabilities, net of current portion	85,542	$ 78,685
Total lease liability	$ 91,294

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Liabilities recorded for agreements	$ 0	$ 0
Contingency loss	0
Provision for contingency loss	0
Agreement with Financial Institution
Loss Contingencies [Line Items]
Letters of credit outstanding amount	$ 2,700,000
Agreement with Financial Institution | Minimum [Member]
Loss Contingencies [Line Items]
Letter of credit notice period by financial institution before annual expiration date	30 days
Agreement with Financial Institution | Maximum
Loss Contingencies [Line Items]
Letter of credit notice period by financial institution before annual expiration date	60 days

CRISPR Collaboration Agreement

CRISPR Collaboration Agreement - Additional Information (Details) - Research Collaboration Agreement		3 Months Ended
	May 05, 2021 CrisprCas9	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Development and Regulatory Approval Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Reduction of research and development expense resulting from partial reimbursement		$ 900,000	$ 1,000,000
Receivable under research cost sharing provision		$ 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
NK Cell Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of non-exclusive rights to gene editing targets licenses received | CrisprCas9	4
NK Cell Products | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of non-exclusive rights to gene editing targets | CrisprCas9	1
Specified TA | Development and Regulatory Approval Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential future payments		totaling less than high-forty million dollars

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value of stock option	$ 4.22
Unrecognized compensation cost	$ 35.2
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	2 years 9 months 18 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to repurchase	113	508
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 6
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	3 years 6 months
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock authorized for issuance	1,441,307
Number of common stock available for issuance	1,379,553
Maximum percentage of employee compensation eligible for plan	15%
Commons stock purchase price as percentage of fair value	85%
Shares issued	61,754
Unrecognized compensation cost	$ 0.1
Unrecognized compensation cost, expected to be recognized over weighted average remaining service period	2 months 12 days
2020 Employee Stock Purchase Plan | Accrued and Other Current Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee contributions to ESPP	$ 0.5
2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock authorized for issuance	8,388,917
Increase in share limit as percentage of outstanding shares of common stock on last trading day in prior year	5%
Number of common stock available for issuance	2,424,272

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity (Details) - 2020 Plan and 2015 Plan - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, outstanding beginning balance	5,519,275
Number of shares, granted	1,363,428
Number of shares, exercised	(253)
Number of shares, forfeited	(62,354)
Number of shares, outstanding ending balance	6,820,096	5,519,275
Number of shares, exercisable	2,697,880
Number of shares, vested and expected to vest	6,820,096
Weighted-average exercise price, outstanding beginning balance	$ 17.17
Weighted-average exercise price, granted	5.54
Weighted-average exercise price, exercised	3.89
Weighted-average exercise price, forfeited	14.52
Weighted-average exercise price, outstanding ending balance	14.87	$ 17.17
Weighted-average exercise price, exercisable	17.16
Weighted-average exercise price, vested and expected to vest	$ 14.87
Weighted-average remaining contractual term (in years), outstanding balance	8 years 3 months 18 days	8 years 1 month 6 days
Weighted-average remaining contractual term (in years), exercisable	7 years 3 months 18 days
Weighted-average remaining contractual term (in years), vested and expected to vest	8 years 3 months 18 days

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Unit Activity	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, outstanding beginning balance | shares	356,728
Number of shares, granted | shares	503,639
Number of shares, Vested | shares	(50,469)
Number of shares, forfeited | shares	(9,968)
Number of shares, outstanding ending balance | shares	799,930
Weighted-average grant date fair value per share, outstanding beginning balance | $ / shares	$ 12.66
Weighted-average grant date fair value per share, granted | $ / shares	5.57
Weighted-average grant date fair value per share, Vested | $ / shares	12.14
Weighted-average grant date fair value per share, Forfeited | $ / shares	9.31
Weighted-average grant date fair value per share, outstanding ending balance | $ / shares	$ 8.27

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 4,746	$ 4,097
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	2,082	1,855
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 2,664	$ 2,242

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0