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.

Collaboration and License Agreements

12 Months Ended

Dec. 31, 2022

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.