Collaboration and License Agreements	3 Months Ended
Mar. 31, 2022
Disclosure Text Block [Abstract]
Collaboration and License Agreements	Collaboration and License Agreements Shenzhen Salubris Pharmaceuticals Co. Ltd. License Agreement On November 30, 2018, the Company entered into a License Agreement (the “Salubris Agreement”) with Shenzhen Salubris Pharmaceutical Co. Ltd., (“Salubris”), pursuant to which the Company granted an exclusive, royalty-bearing license, with the right to grant sublicenses to Salubris to research, develop, use, make, have made, sell, offer for sale, have sold, import, and otherwise commercialize nanatinostat in combination with an antiviral drug such as valganciclovir in the Republic of China, excluding Hong Kong, Macau, and Taiwan. On August 19, 2021, the Company, through its wholly-owned subsidiary, Viracta Subsidiary, Inc., entered into a Mutual Termination Agreement with Salubris, effective August 20, 2021 (the “Termination Agreement”), pursuant to which the parties agreed to terminate the Salubris Agreement. Under the terms of the Termination Agreement, the Company paid Salubris a payment in the amount of $4.0 million on the effective date of the Termination Agreement, and all licenses granted by the Company to Salubris automatically terminated. ImmunityBio License Agreement On May 1, 2017, the Company entered into a License Agreement (the “NK Agreement”) with ImmunityBio, Inc., formerly NantKwest, Inc. (“ImmunityBio”) whereby the Company granted an exclusive worldwide license to ImmunityBio and its affiliates to develop and commercialize nanatinostat for use in combination with NK cell immunotherapies. ImmunityBio will be responsible for conducting all necessary studies, including safety studies and clinical trials necessary in connection with seeking regulatory approvals to market the product in any territory. If ImmunityBio requires nanatinostat, the Company has the right to manufacture nanatinostat to be sold as part of a therapeutic product utilizing nanatinostat at a transfer price related to Viracta’s cost to ImmunityBio. In accordance with the NK Agreement, the Company is also eligible to receive up to a total of $100.0 million in milestone payments, with respect to the licensed products. The Company is eligible to earn tiered royalties on net sales of licensed products by ImmunityBio, its affiliates or sublicensees, ranging from the low to mid-single digits. The Company has recognized no revenue from milestones (variable consideration), which are fully constrained, or royalties to date. Unless earlier terminated, the NK Agreement will continue until the expiration of all applicable royalty terms on a product-by-product and country-by-country basis. There are no performance, cancellation, termination, or refund provisions in the arrangement that contain material financial consequences to the Company.

Collaboration and License Agreements

3 Months Ended

Mar. 31, 2022

Shenzhen Salubris Pharmaceuticals Co. Ltd. License Agreement

On November 30, 2018, the Company entered into a License Agreement (the “Salubris Agreement”) with Shenzhen Salubris Pharmaceutical Co. Ltd., (“Salubris”), pursuant to which the Company granted an exclusive, royalty-bearing license, with the right to grant sublicenses to Salubris to research, develop, use, make, have made, sell, offer for sale, have sold, import, and otherwise commercialize nanatinostat in combination with an antiviral drug such as valganciclovir in the Republic of China, excluding Hong Kong, Macau, and Taiwan.

On August 19, 2021, the Company, through its wholly-owned subsidiary, Viracta Subsidiary, Inc., entered into a Mutual Termination Agreement with Salubris, effective August 20, 2021 (the “Termination Agreement”), pursuant to which the parties agreed to terminate the Salubris Agreement. Under the terms of the Termination Agreement, the Company paid Salubris a payment in the amount of $4.0 million on the effective date of the Termination Agreement, and all licenses granted by the Company to Salubris automatically terminated.

ImmunityBio License Agreement

On May 1, 2017, the Company entered into a License Agreement (the “NK Agreement”) with ImmunityBio, Inc., formerly NantKwest, Inc. (“ImmunityBio”) whereby the Company granted an exclusive worldwide license to ImmunityBio and its affiliates to develop and commercialize nanatinostat for use in combination with NK cell immunotherapies. ImmunityBio will be responsible for conducting all necessary studies, including safety studies and clinical trials necessary in connection with seeking regulatory approvals to market the product in any territory. If ImmunityBio requires nanatinostat, the Company has the right to manufacture nanatinostat to be sold as part of a therapeutic product utilizing nanatinostat at a transfer price related to Viracta’s cost to ImmunityBio.

In accordance with the NK Agreement, the Company is also eligible to receive up to a total of $100.0 million in milestone payments, with respect to the licensed products. The Company is eligible to earn tiered royalties on net sales of licensed products by ImmunityBio, its affiliates or sublicensees, ranging from the low to mid-single digits. The Company has recognized no revenue from milestones (variable consideration), which are fully constrained, or royalties to date.

Unless earlier terminated, the NK Agreement will continue until the expiration of all applicable royalty terms on a product-by-product and country-by-country basis. There are no performance, cancellation, termination, or refund provisions in the arrangement that contain material financial consequences to the Company.