Collaborative Agreements	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Agreements	Collaborative Agreements ApolloBio Corporation In 2017, the Company entered into an Amended and Restated License and Collaboration Agreement (the "ApolloBio Agreement"), with ApolloBio Corporation ("ApolloBio"), which was amended in June 2023. Under the terms of the ApolloBio Agreement, the Company granted to ApolloBio the exclusive right to develop and commercialize VGX-3100, its DNA immunotherapy product candidate designed to treat pre-cancers caused by HPV, within the agreed upon territories. The Company is entitled to receive up to an aggregate of $20.0 million, less required income, withholding or other taxes, upon the achievement of specified milestones related to the regulatory approval of VGX-3100 in accordance with the ApolloBio Agreement. In the event that VGX-3100 is approved for marketing, the Company will be entitled to receive royalty payments based on a tiered percentage of annual net sales, with such percentage being in the low- to mid-teens, subject to reduction in the event of generic competition in a particular territory. ApolloBio’s obligation to pay royalties will continue for 10 years after the first commercial sale in a particular territory or, if later, until the expiration of the last-to-expire patent covering the licensed products in the specified territory. During the three and six months ended June 30, 2025, the Company received $0 and $65,000, respectively, from the ApolloBio Agreement that was recorded as revenue. During each of the three and six months ended June 30, 2024, the Company received funding of $101,000 from the ApolloBio Agreement that was recorded as revenue. Coalition for Epidemic Preparedness Innovations The Company previously entered into agreements with the Coalition for Epidemic Preparedness Innovations (CEPI), pursuant to which the Company intended to develop vaccine candidates against Lassa fever and MERS. As part of the arrangement between the parties, CEPI agreed to fund up to an aggregate of $56 million of costs over a five-year period for preclinical studies, as well as planned Phase 1 and Phase 2 clinical trials, to be conducted by the Company and collaborators, with funding from CEPI based on the achievement of identified milestones. In 2022, the Company announced that it and CEPI would discontinue the development of these product candidates targeting Lassa fever and MERS, following the initial analysis of data from the studies conducted by the Company and funded by CEPI. During the three and six months ended June 30, 2024 or 2025, no amounts were recorded as contra-research and development expense related to the CEPI grants. In the third quarter of 2024, the Company received funding of $1.6 million in connection with the final close-out of these grants. Bill & Melinda Gates Foundation In 2018, Gates awarded and funded the Company a grant of $2.2 million to advance the development of DMAbs to address issues in infectious disease prevention and therapy. This technology has high relevance for the control of influenza and HIV. This next-generation approach to the delivery of monoclonal antibodies would make the technology accessible to low and middle-income countries. In 2019, Gates funded an additional $1.1 million for the project. During the three and six months ended June 30, 2024, the Company recorded $0 and $39,000, respectively, as contra-research and development expense related to the grant, which was closed out in the first quarter of 2024.

In 2017, the Company entered into an Amended and Restated License and Collaboration Agreement (the "ApolloBio Agreement"), with ApolloBio Corporation ("ApolloBio"), which was amended in June 2023. Under the terms of the ApolloBio Agreement, the Company granted to ApolloBio the exclusive right to develop and commercialize VGX-3100, its DNA immunotherapy product candidate designed to treat pre-cancers caused by HPV, within the agreed upon territories.

The Company is entitled to receive up to an aggregate of $20.0 million, less required income, withholding or other taxes, upon the achievement of specified milestones related to the regulatory approval of VGX-3100 in accordance with the ApolloBio Agreement. In the event that VGX-3100 is approved for marketing, the Company will be entitled to receive royalty payments based on a tiered percentage of annual net sales, with such percentage being in the low- to mid-teens, subject to reduction in the event of generic competition in a particular territory. ApolloBio’s obligation to pay royalties will continue for 10 years after the first commercial sale in a particular territory or, if later, until the expiration of the last-to-expire patent covering the licensed products in the specified territory.

During the three and six months ended June 30, 2025, the Company received $0 and $65,000, respectively, from the ApolloBio Agreement that was recorded as revenue. During each of the three and six months ended June 30, 2024, the Company received funding of $101,000 from the ApolloBio Agreement that was recorded as revenue.

The Company previously entered into agreements with the Coalition for Epidemic Preparedness Innovations (CEPI), pursuant to which the Company intended to develop vaccine candidates against Lassa fever and MERS. As part of the arrangement between the parties, CEPI agreed to fund up to an aggregate of $56 million of costs over a five-year period for preclinical studies, as well as planned Phase 1 and Phase 2 clinical trials, to be conducted by the Company and collaborators, with funding from CEPI based on the achievement of identified milestones. In 2022, the Company announced that it and CEPI would discontinue the development of these product candidates targeting Lassa fever and MERS, following the initial analysis of data from the studies conducted by the Company and funded by CEPI.

During the three and six months ended June 30, 2024 or 2025, no amounts were recorded as contra-research and development expense related to the CEPI grants. In the third quarter of 2024, the Company received funding of $1.6 million in connection with the final close-out of these grants.

In 2018, Gates awarded and funded the Company a grant of $2.2 million to advance the development of DMAbs to address issues in infectious disease prevention and therapy. This technology has high relevance for the control of influenza and HIV. This next-generation approach to the delivery of monoclonal antibodies would make the technology accessible to low and middle-income countries. In 2019, Gates funded an additional $1.1 million for the project. During the three and six months ended June 30, 2024, the Company recorded $0 and $39,000, respectively, as contra-research and development expense related to the grant, which was closed out in the first quarter of 2024.