Collaborative Arrangements	12 Months Ended
Dec. 31, 2024
Research and Development [Abstract]
Collaborative Arrangements	Collaborative Arrangements Merck Sitagliptin Catalyst Supply Agreement In February 2012, we entered into a five-year Sitagliptin Catalyst Supply Agreement (“Sitagliptin Supply Agreement”) with Merck whereby Merck may obtain commercial scale enzyme for use in the manufacture of Januvia, its product based on the active ingredient sitagliptin. In December 2015, Merck exercised its options under the terms of the Sitagliptin Supply Agreement to extend the agreement for an additional five years through February 2022. In September 2021, the Sitagliptin Supply Agreement was amended to extend the agreement through December 2026. Effective as of January 2016, we and Merck amended the Sitagliptin Supply Agreement to prospectively provide for variable pricing based on the cumulative volume of sitagliptin enzyme purchased by Merck. We have previously determined that the variable pricing, which provides a discount based on the cumulative volume of sitagliptin enzyme purchased by Merck, provides Merck material rights and we recognized product revenues using the alternative method wherein we estimated the total expected consideration and allocated it proportionately with the expected sales. Pursuant to the latest amendment of the Sitagliptin Supply Agreement, we have determined that the latest price per volume of sitagliptin enzyme to be purchased by Merck no longer provides Merck material rights, and as such we are recognizing product revenue based on contractually stated prices effective as of February 2022. We recognized $7.1 million, $4.4 million and $5.9 million in product revenue under this agreement in the years ended December 31, 2024, 2023 and 2022, respectively. This represented 12%, 6%, and 4% of our total revenues in the years ended December 31, 2024, 2023 and 2022, respectively. During the year ended December 31, 2024, we recorded revenue of $2.5 million from sitagliptin enzyme sales that were recognized over time based on the progress of the manufacturing process. These products will be shipped within the three-month period following the end of 2024. Enzyme Supply Agreement and Commercial Agreement In November 2016, we entered into an enzyme supply agreement with a customer, receiving an upfront payment recorded as deferred revenue which was recognized as the customer purchased our enzyme. In April 2019, we entered into a multi-year commercial agreement with the same customer for the exclusive use of our enzymes in some of their products, with royalties to be earned. Both the enzyme supply agreement and commercial agreement were terminated in 2023. Due to the early termination of the enzyme supply agreement in 2023, we recognized $3.2 million of product revenue from the release of prior periods' product revenue deferrals and also recognized an additional $1.3 million of product revenue as settlement fee. Strategic Collaboration Agreement In October 2017, we entered into the Nestlé Strategic Collaboration Agreement (the “Nestlé SCA”) with Nestlé, pursuant to which we and Nestlé collaborated to leverage the CodeEvolver technology platform to develop novel enzymes for Nestlé’s established Consumer Care and Medical Nutrition business areas. In January 2020, we entered into a development agreement with Nestlé pursuant to which we and Nestlé collaborated to advance a lead candidate discovered through our Nestlé SCA, CDX-7108, targeting exocrine pancreatic insufficiency, into preclinical and early clinical studies. We, together with Nestlé Health Science, initiated a Phase 1 clinical trial of CDX-7108 in the fourth quarter of 2021, and on February 23, 2023, we and Nestlé announced interim results. In July 2023, we announced plans to discontinue our development support of CDX-7108. Both the Nestlé SCA and development agreement were terminated in January 2024 under the terms of the CDX-7108 Acquisition Agreement with Nestlé. Under the Nestlé SCA and the development agreement, we recognized nil, $4.1 million and $7.1 million in research and development revenue in the years ended December 31, 2024, 2023 and 2022, respectively. Acquisition Agreement In December 2023, we entered into an acquisition agreement (the “Acquisition Agreement”) with Nestlé, pursuant to which we agreed to assign our interests in CDX-7108 (including associated agreements and intellectual property rights) to Nestlé. Under the terms of the Acquisition Agreement, Nestlé will be solely responsible for the continued development and commercialization of CDX-7108, including all associated costs, and Codexis will receive upfront payment, future potential milestone payments and net-sales based royalties. We recognized $5.0 million in research and development revenue for the year ended December 31, 2023 related to the Acquisition Agreement, with the $5.0 million upfront fee received in January 2024. Platform Technology Transfer and License Agreement In May 2019, we entered into the Novartis CodeEvolver Agreement with Novartis. The Novartis CodeEvolver Agreement allows Novartis to use our proprietary CodeEvolver technology platform in the field of human healthcare. In July 2021, we announced the completion of the technology transfer period during which we transferred our proprietary CodeEvolver technology platform to Novartis (the “Technology Transfer Period”). As a part of this technology transfer, we provided to Novartis our proprietary enzymes, proprietary protein engineering protocols and methods, and proprietary software algorithms. In addition, our teams and Novartis scientists participated in technology training sessions and collaborative research projects at our laboratories in Redwood City, California and at a designated Novartis laboratory in Basel, Switzerland. Novartis has now installed the CodeEvolver technology platform at its designated laboratory. Pursuant to the agreement, we received an upfront payment of $5.0 million shortly after the effective date of the Novartis CodeEvolver Agreement. We completed the second technology milestone transfer under the agreement in 2020 and received a milestone payment of $4.0 million. We have also received an aggregate of $5.0 million for the completion of the third technology milestone in 2021. In consideration for the continued disclosure and license of improvements to the technology and materials during a multi-year period that began on the conclusion of the Technology Transfer Period (the “Improvements Term”), Novartis will pay Codexis annual payments over four years which amount to an additional $8.0 million in aggregate. We received an aggregate of $6.0 million for the first three annual payments in 2022 to 2024. The Company also has the potential to receive quantity-dependent, usage payments for each API that is manufactured by Novartis using one or more enzymes that have been developed or are in development using the CodeEvolver technology platform during the period beginning on the conclusion of the Technology Transfer Period and ending on the expiration date of the last to expire licensed patent. Revenue for the combined initial license and technology transfer performance obligation was recognized overtime based on hours incurred. Revenue allocated to improvements made during the Improvements Term is being recognized during the Improvements Term. We recognized $1.0 million, $1.1 million and $1.0 million in research and development revenue in the years ended December 31, 2024, 2023 and 2022, respectively. License Agreement In December 2019, we entered a license agreement with Roche to provide Roche with our evolved T4 DNA ligase high-performance molecular diagnostic enzyme. The royalty bearing license grants Roche worldwide rights to include the evolved T4 DNA ligase in its nucleic acid sequencing products and workflows. Under the license agreement, we received an initial collaboration fee payment of $0.8 million within 45 days of the effective date of the agreement, and we received an additional $0.9 million milestone payment after the completion of technology transfer in October 2020. In February 2024, we entered into a new license agreement with Roche granting them rights to our newly engineered DNA ligase, superseding our prior 2019 agreement. Under the terms of the deal, we received upfront and technical milestones payments. We recognized research and development fees of $6.0 million in the year ended December 31, 2024 related to the license agreement. Strategic Collaboration and License Agreement In March 2020, we entered into a Strategic Collaboration and License Agreement (the “Takeda Agreement”) with Shire Human Genetic Therapies, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Co. Ltd. (“Takeda”), pursuant to which we have collaborated with Takeda to research and develop protein sequences for use in gene therapy products for certain diseases in accordance with each applicable program plan. On execution of the Takeda Agreement, we received an upfront non-refundable cash payment of $8.5 million and we initiated activities under three program plans for Fabry Disease, Pompe Disease, and an undisclosed blood factor deficiency, respectively (the “Initial Programs”). In May 2021, Takeda elected to exercise its option to initiate an additional program for a certain undisclosed rare genetic disorder; as a result we received the option exercise fee during the third quarter of 2021. We completed the research and development services relating to the fourth program with Takeda during the second quarter of 2023. Pursuant to the Takeda Agreement, we were eligible to receive other payments that included (i) clinical development and commercialization-based milestones, per target gene, of up to $104.0 million and (ii) tiered royalty payments based on net sales of applicable products at percentages ranging from the mid-single digits to low single-digits. Takeda announced in April 2023 the discontinuation of these development programs, and in 2024 we divested our rights in some of the underlying assets to Crosswalk Therapeutics. Revenue relating to the functional licenses provided to Takeda was recognized at a point in time when the control of the license transferred to the customer. We recognized research and development revenue related to the Takeda Agreement of $0.8 million, $2.0 million and $4.9 million in the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024 and 2023, we had deferred revenue balances of nil. Master Collaboration and Research Agreement, Stock Purchase Agreement and Enzyme Supply Agreement In June 2020, we entered into a Stock Purchase Agreement with MAI in which we purchased 1,587,050 shares of MAI's Series A preferred stock for $1.0 million. Concurrently with our initial equity investment, we entered into the MAI Agreement, pursuant to which we performed services utilizing our CodeEvolver technology platform to improve DNA polymerase enzymes in exchange for compensation in the form of additional shares of MAI's Series A and B preferred stock which are valued based on the observed transaction price of similar securities of MAI issued to third parties. Under the MAI Agreement, we will have the right to use and sell the engineered enzymes to third parties for any purpose other than for the synthesis of native DNA. Under the MAI Agreement, we would make a $0.5 million payment to MAI upon our achievement of a milestone of $5.0 million in aggregate commercial sales to third parties of the engineered enzymes or any product incorporating or derived from the engineered enzymes for any purpose other than the synthesis of native DNA. As contemplated in the MAI Agreement, we executed the Commercial License and Enzyme Supply Agreement with MAI (“MAI Supply Agreement”) in July 2022 following the completion of certain timelines specified in the SOW. We completed the R&D service with MAI pursuant to the MAI Agreement during the first quarter of 2022. In December 2021, we received the primary milestone payment pursuant to the MAI Agreement of $1.0 million in the form of an additional 1,587,049 shares of MAI Series B preferred stock. Upon execution of the MAI Supply Agreement in July 2022, we received the commercialization and enzyme supply agreement milestone payment pursuant to the MAI Agreement of $1.0 million in the form of an additional 1,587,049 shares of MAI Series B preferred stock. Pursuant to the MAI Agreement, we recognized nil , nil, and $1.2 million in research and development revenue from transactions with MAI in the years ended December 31, 2024, 2023, and 2022, respectively. Payment for the services rendered was received in the form of additional MAI Series A and Series B preferred stock. We received an aggregate of nil, nil, and 1,587,049 shares of MAI's Series A and B preferred stock in the years ended December 31, 2024, 2023, and 2022, respectively. In April 2022, we received a purchase order from MAI for the delivery of certain enzyme products to MAI in 2022. In July 2022, we and MAI executed the MAI Supply Agreement that will enable MAI to utilize an evolved terminal deoxynucleotidyl transferase enzyme in MAI’s Fully Enzymatic Synthesis technology. Pursuant to the MAI Supply Agreement, we recognized $0.1 million of minimum royalty as part of the research and development revenue in the year ended December 31, 2024. In January 2025, MAI assigned the MAI Supply Agreement to a third party in connection with the sale of its related assets to such third party. We recognized $0.2 million, $0.2 million, and $0.5 million in product revenue in the years ended December 31, 2024, 2023, and 2022, respectively. MAI was considered a related party until August 2022, when the related party relationship ended following the retirement of our former President and CEO, who also served on MAI’s board of directors. Pfizer Enzyme Supply Agreement During 2021 and 2022, we received purchase orders from Pfizer for large quantities of our proprietary enzyme product, CDX-616, for use by Pfizer in the manufacture of a critical intermediate for its proprietary active pharmaceutical ingredient, nirmatrelvir, used by Pfizer in combination with the active pharmaceutical ingredient ritonavir, as its PAXLOVID (nirmatrelvir tablets; ritonavir tablets) product for the treatment of COVID-19 infections in humans. We are a party to an Enzyme Supply Agreement with Pfizer Ireland Pharmaceuticals, a subsidiary of Pfizer, Inc. (the “Pfizer Supply Agreement”), covering the manufacture, sale and purchase of CDX-616 for use by Pfizer in the manufacture of nirmatrelvir. Under the terms of the Pfizer Supply Agreement, Pfizer paid us a fee of $25.9 million in August 2022 which was recorded as deferred revenue. Pursuant to the agreement, 90% of the fee ($23.3 million) is creditable against (i) future orders of CDX-616 used to manufacture its PAXLOVID with shipment dates prior to December 31, 2023, and (ii) fees associated with any new development and licensing agreements with Pfizer entered into prior to April 4, 2023. On March 31, 2023, we entered into a license agreement whereby Pfizer utilized a portion of the $23.3 million credit towards a license to develop future product candidates, for which we recognized $5.0 million as non-cash research and development revenue in the second quarter of 2023. Pfizer's ability to utilize the credit under item (i) above expired on December 31, 2023, and under item (ii) above expired on April 4, 2023. We also recognized $2.0 million of non-cash research and development revenue, and credited against the $25.9 million fee, for other services provided to Pfizer during the year ended December 31, 2023. Up to 50% of any portion of the $25.9 million which has not been credited under items (i) and (ii) was creditable against future orders of CDX-616 used to manufacture PAXLOVID with shipment dates in 2024. On December 20, 2024, we entered into a license agreement whereby Pfizer utilized the remaining credit toward the upfront fee under the license agreement, pursuant to the terms of the same-day amendment to the Pfizer Supply Agreement that allowed the product credit to be utilized for this license. We recognized $9.5 million of non-cash research and development revenue in the year ended December 31, 2024 related to the license agreement, and no further credit remains available for Pfizer. During the fourth quarter of 2023, and pursuant to the Pfizer Supply Agreement, we released the prior year deferrals for the unused portion of the retainer fee that is not creditable beyond 2023 and we recognized product revenue of $8.2 million in the year ended December 31, 2023. We recognized product revenue of $75.4 million in the year ended December 31, 2022, from the sale of quantities of CDX-616 to Pfizer. Product revenues recognized by us from the Pfizer Supply Agreement represented 0%, 12%, and 54% of our total revenues for the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024 and 2023, we had nil and $9.5 million, respectively, in deferred revenue related to the $25.9 million fee received from Pfizer.

In February 2012, we entered into a five-year Sitagliptin Catalyst Supply Agreement (“Sitagliptin Supply Agreement”) with Merck whereby Merck may obtain commercial scale enzyme for use in the manufacture of Januvia, its product based on the active ingredient sitagliptin. In December 2015, Merck exercised its options under the terms of the Sitagliptin Supply Agreement to extend the agreement for an additional five years through February 2022. In September 2021, the Sitagliptin Supply Agreement was amended to extend the agreement through December 2026.

Effective as of January 2016, we and Merck amended the Sitagliptin Supply Agreement to prospectively provide for variable pricing based on the cumulative volume of sitagliptin enzyme purchased by Merck. We have previously determined that the variable pricing, which provides a discount based on the cumulative volume of sitagliptin enzyme purchased by Merck, provides Merck material rights and we recognized product revenues using the alternative method wherein we estimated the total expected consideration and allocated it proportionately with the expected sales. Pursuant to the latest amendment of the Sitagliptin Supply Agreement, we have determined that the latest price per volume of sitagliptin enzyme to be purchased by Merck no longer provides Merck material rights, and as such we are recognizing product revenue based on contractually stated prices effective as of February 2022.

In November 2016, we entered into an enzyme supply agreement with a customer, receiving an upfront payment recorded as deferred revenue which was recognized as the customer purchased our enzyme. In April 2019, we entered into a multi-year commercial agreement with the same customer for the exclusive use of our enzymes in some of their products, with royalties to be earned. Both the enzyme supply agreement and commercial agreement were terminated in 2023. Due to the early termination of the enzyme supply agreement in 2023, we recognized $3.2 million of product revenue from the release of prior periods' product revenue deferrals and also recognized an additional $1.3 million of product revenue as settlement fee.

In October 2017, we entered into the Nestlé Strategic Collaboration Agreement (the “Nestlé SCA”) with Nestlé, pursuant to which we and Nestlé collaborated to leverage the CodeEvolver technology platform to develop novel enzymes for Nestlé’s established Consumer Care and Medical Nutrition business areas.

In January 2020, we entered into a development agreement with Nestlé pursuant to which we and Nestlé collaborated to advance a lead candidate discovered through our Nestlé SCA, CDX-7108, targeting exocrine pancreatic insufficiency, into preclinical and early clinical studies. We, together with Nestlé Health Science, initiated a Phase 1 clinical trial of CDX-7108 in the fourth quarter of 2021, and on February 23, 2023, we and Nestlé announced interim results. In July 2023, we announced plans to discontinue our development support of CDX-7108. Both the Nestlé SCA and development agreement were terminated in January 2024 under the terms of the CDX-7108 Acquisition Agreement with Nestlé.

In December 2023, we entered into an acquisition agreement (the “Acquisition Agreement”) with Nestlé, pursuant to which we agreed to assign our interests in CDX-7108 (including associated agreements and intellectual property rights) to Nestlé. Under the terms of the Acquisition Agreement, Nestlé will be solely responsible for the continued development and commercialization of CDX-7108, including all associated costs, and Codexis will receive upfront payment, future potential milestone payments and net-sales based royalties. We recognized $5.0 million in research and development revenue for the year ended December 31, 2023 related to the Acquisition Agreement, with the $5.0 million upfront fee received in January 2024.

In May 2019, we entered into the Novartis CodeEvolver Agreement with Novartis. The Novartis CodeEvolver Agreement allows Novartis to use our proprietary CodeEvolver technology platform in the field of human healthcare. In July 2021, we announced the completion of the technology transfer period during which we transferred our proprietary CodeEvolver technology platform to Novartis (the “Technology Transfer Period”). As a part of this technology transfer, we provided to Novartis our proprietary enzymes, proprietary protein engineering protocols and methods, and proprietary software algorithms. In addition, our teams and Novartis scientists participated in technology training sessions and collaborative research projects at our laboratories in Redwood City, California and at a designated Novartis laboratory in Basel, Switzerland. Novartis has now installed the CodeEvolver technology platform at its designated laboratory.

Pursuant to the agreement, we received an upfront payment of $5.0 million shortly after the effective date of the Novartis CodeEvolver Agreement. We completed the second technology milestone transfer under the agreement in 2020 and received a milestone payment of $4.0 million. We have also received an aggregate of $5.0 million for the completion of the third technology milestone in 2021. In consideration for the continued disclosure and license of improvements to the technology and materials during a multi-year period that began on the conclusion of the Technology Transfer Period (the “Improvements Term”), Novartis will pay Codexis annual payments over four years which amount to an additional $8.0 million in aggregate. We received an aggregate of $6.0 million for the first three annual payments in 2022 to 2024. The Company also has the potential to receive quantity-dependent, usage payments for each API that is manufactured by Novartis using one or more enzymes that have been developed or are in development using the CodeEvolver technology platform during the period beginning on the conclusion of the Technology Transfer Period and ending on the expiration date of the last to expire licensed patent. Revenue for the combined initial license and technology transfer performance obligation was recognized overtime based on hours incurred. Revenue allocated to improvements made during the Improvements Term is being recognized during the Improvements Term.

In December 2019, we entered a license agreement with Roche to provide Roche with our evolved T4 DNA ligase high-performance molecular diagnostic enzyme. The royalty bearing license grants Roche worldwide rights to include the evolved T4 DNA ligase in its nucleic acid sequencing products and workflows. Under the license agreement, we received an initial collaboration fee payment of $0.8 million within 45 days of the effective date of the agreement, and we received an additional $0.9 million milestone payment after the completion of technology transfer in October 2020. In February 2024, we entered into a new license agreement with Roche granting them rights to our newly engineered DNA ligase, superseding our prior 2019 agreement. Under the terms of the deal, we received upfront and technical milestones payments. We recognized research and development fees of $6.0 million in the year ended December 31, 2024 related to the license agreement.

In March 2020, we entered into a Strategic Collaboration and License Agreement (the “Takeda Agreement”) with Shire Human Genetic Therapies, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Co. Ltd. (“Takeda”), pursuant to which we have collaborated with Takeda to research and develop protein sequences for use in gene therapy products for certain diseases in accordance with each applicable program plan.

On execution of the Takeda Agreement, we received an upfront non-refundable cash payment of $8.5 million and we initiated activities under three program plans for Fabry Disease, Pompe Disease, and an undisclosed blood factor deficiency, respectively (the “Initial Programs”). In May 2021, Takeda elected to exercise its option to initiate an additional program for a certain undisclosed rare genetic disorder; as a result we received the option exercise fee during the third quarter of 2021. We completed the research and development services relating to the fourth program with Takeda during the second quarter of 2023.

Pursuant to the Takeda Agreement, we were eligible to receive other payments that included (i) clinical development and commercialization-based milestones, per target gene, of up to $104.0 million and (ii) tiered royalty payments based on net sales of applicable products at percentages ranging from the mid-single digits to low single-digits. Takeda announced in April 2023 the discontinuation of these development programs, and in 2024 we divested our rights in some of the underlying assets to Crosswalk Therapeutics.

Revenue relating to the functional licenses provided to Takeda was recognized at a point in time when the control of the license transferred to the customer. We recognized research and development revenue related to the Takeda Agreement of $0.8 million, $2.0 million and $4.9 million in the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024 and 2023, we had deferred revenue balances of nil.

Concurrently with our initial equity investment, we entered into the MAI Agreement, pursuant to which we performed services utilizing our CodeEvolver technology platform to improve DNA polymerase enzymes in exchange for compensation in the form of additional shares of MAI's Series A and B preferred stock which are valued based on the observed transaction price of similar securities of MAI issued to third parties. Under the MAI Agreement, we will have the right to use and sell the engineered enzymes to third parties for any purpose other than for the synthesis of native DNA. Under the MAI Agreement, we would make a $0.5 million payment to MAI upon our achievement of a milestone of $5.0 million in aggregate commercial sales to third parties of the engineered enzymes or any product incorporating or derived from the engineered enzymes for any purpose other than the synthesis of native DNA. As contemplated in the MAI Agreement, we executed the Commercial License and Enzyme Supply Agreement with MAI (“MAI Supply Agreement”) in July 2022 following the completion of certain timelines specified in the SOW.

We completed the R&D service with MAI pursuant to the MAI Agreement during the first quarter of 2022. In December 2021, we received the primary milestone payment pursuant to the MAI Agreement of $1.0 million in the form of an additional 1,587,049 shares of MAI Series B preferred stock. Upon execution of the MAI Supply Agreement in July 2022, we received the commercialization and enzyme supply agreement milestone payment pursuant to the MAI Agreement of $1.0 million in the form of an additional 1,587,049 shares of MAI Series B preferred stock. Pursuant to the MAI Agreement, we recognized nil , nil, and $1.2 million in research and development revenue from transactions with MAI in the years ended December 31, 2024, 2023, and 2022, respectively. Payment for the services rendered was received in the form of additional MAI Series A and Series B preferred stock. We received an aggregate of nil, nil, and 1,587,049 shares of MAI's Series A and B preferred stock in the years ended December 31, 2024, 2023, and 2022, respectively.

In April 2022, we received a purchase order from MAI for the delivery of certain enzyme products to MAI in 2022. In July 2022, we and MAI executed the MAI Supply Agreement that will enable MAI to utilize an evolved terminal deoxynucleotidyl transferase enzyme in MAI’s Fully Enzymatic Synthesis technology. Pursuant to the MAI Supply Agreement, we recognized $0.1 million of minimum royalty as part of the research and development revenue in the year ended December 31, 2024. In January 2025, MAI assigned the MAI Supply Agreement to a third party in connection with the sale of its related assets to such third party. We recognized $0.2 million, $0.2 million, and $0.5 million in product revenue in the years ended December 31, 2024, 2023, and 2022, respectively.

During 2021 and 2022, we received purchase orders from Pfizer for large quantities of our proprietary enzyme product, CDX-616, for use by Pfizer in the manufacture of a critical intermediate for its proprietary active pharmaceutical ingredient, nirmatrelvir, used by Pfizer in combination with the active pharmaceutical ingredient ritonavir, as its PAXLOVID (nirmatrelvir tablets; ritonavir tablets) product for the treatment of COVID-19 infections in humans.

We are a party to an Enzyme Supply Agreement with Pfizer Ireland Pharmaceuticals, a subsidiary of Pfizer, Inc. (the “Pfizer Supply Agreement”), covering the manufacture, sale and purchase of CDX-616 for use by Pfizer in the manufacture of nirmatrelvir. Under the terms of the Pfizer Supply Agreement, Pfizer paid us a fee of $25.9 million in August 2022 which was recorded as deferred revenue. Pursuant to the agreement, 90% of the fee ($23.3 million) is creditable against (i) future orders of CDX-616 used to manufacture its PAXLOVID with shipment dates prior to December 31, 2023, and (ii) fees associated with any new development and licensing agreements with Pfizer entered into prior to April 4, 2023. On March 31, 2023, we entered into a license agreement whereby Pfizer utilized a portion of the $23.3 million credit towards a license to develop future product candidates, for which we recognized $5.0 million as non-cash research and development revenue in the second quarter of 2023. Pfizer's ability to utilize the credit under item (i) above expired on December 31, 2023, and under item (ii) above expired on April 4, 2023. We also recognized $2.0 million of non-cash research and development revenue, and credited against the $25.9 million fee, for other services provided to Pfizer during the year ended December 31, 2023. Up to 50% of any portion of the $25.9 million which has not been credited under items (i) and (ii) was creditable against future orders of CDX-616 used to manufacture PAXLOVID with shipment dates in 2024.

On December 20, 2024, we entered into a license agreement whereby Pfizer utilized the remaining credit toward the upfront fee under the license agreement, pursuant to the terms of the same-day amendment to the Pfizer Supply Agreement that allowed the product credit to be utilized for this license. We recognized $9.5 million of non-cash research and development revenue in the year ended December 31, 2024 related to the license agreement, and no further credit remains available for Pfizer.

During the fourth quarter of 2023, and pursuant to the Pfizer Supply Agreement, we released the prior year deferrals for the unused portion of the retainer fee that is not creditable beyond 2023 and we recognized product revenue of $8.2 million in the year ended December 31, 2023. We recognized product revenue of $75.4 million in the year ended December 31, 2022, from the sale of quantities of CDX-616 to Pfizer. Product revenues recognized by us from the Pfizer Supply Agreement represented 0%, 12%, and 54% of our total revenues for the years ended December 31, 2024, 2023, and 2022, respectively.