Note 15 - Subsequent Events	12 Months Ended
Dec. 31, 2024
Notes to Financial Statements
Subsequent Events [Text Block]	*NOTE 15.* Subsequent Events** Appointment of Mr. Kevin Finney to Board of Directors On January 24, 2025, following a recommendation by the Nominating and Governance Committee of the Board of Directors, the Company's Board appointed Kevin Finney to serve on the Board, effective January 28, 2025, until Mr. Kevin Finney’s successor is elected and qualified, or sooner in the event of his death, resignation, or removal. The Board has determined that Mr. Kevin Finney meets the requirements for independence under the applicable listing standards of The Nasdaq Stock Market LLC and the Securities Exchange Act of 1934, as amended. Mr. Kevin Finney was also appointed as a member of the Audit Committee and the Nominating and Governance Committee of the Board. Modification of 2024* ATI-RRPV Contract* On February 7, 2025, the Company entered into Modification No. 5 (the “Modification”) to the ATI-RRPV Project Award Agreement No. 001, dated June 13, 2024 (the “Project Agreement”), with Advanced Technology International, the Rapid Response Partnership Vehicle’s Consortium Management Firm funded by BARDA of the U.S. Department of Health and Human Services. As previously disclosed, pursuant to the Project Agreement, the Company received funding to conduct a Phase 2b comparative study (the “Trial”) evaluating the Company’s oral pill COVID-19 vaccine candidate against an mRNA vaccine comparator approved by the U.S. Food and Drug Administration. The Company previously announced that it had completed enrollment of the sentinel cohort portion of the study comprising approximately 400 patients comparing its oral pill XBB candidate against an mRNA XBB comparator and an independent data safety monitoring board recommended the study to proceed without modifications based on initial safety assessment of 30-day data from the sentinel cohort. The Modification increased the total amount of funding currently allotted to the Trial and available for payment to approximately $240.1 million, representing an increase of approximately $105.9 million. The Modification also clarifies the design of the Trial by specifying that the next portion of the Trial will compare the efficacy and safety of the Company’s KP.2 oral vaccine candidate against an mRNA comparator directed against KP.2 and will be comprised of 10,000 participants. The Company is awaiting approval from BARDA to commence dosing in the 10,000-participant portion of the Trial. Stop Work Order Received for the 2024* ATI-RRPV Contract* On February 21, 2025, the Company received written notification from ATI in the form of stop work orders (the “Notices”) directing the Company to stop work on all of the Company’s efforts with respect to the Project Agreement with ATI, the Rapid Response Partnership Vehicle’s Consortium Management Firm funded by HHS BARDA, with the exception that the Company may continue efforts associated with the per protocol follow-up for the 400-person cohort. The Notices stated that the stop work order is in effect for a period of 90 days after the date of the Notices and, that within a period of 90 days, ATI, as directed by the government, will either cancel the stop-work order, extend the stop work, or terminate the work covered by the letter as provided in Article 13.4 of the Project Agreement. Reduction in Operating Costs In the first quarter of 2025, the Company suspended all activities related to the 10,000-participant cohort of its COVID-19 Phase 2b study and implemented additional measures to reduce expenses with specific vendors, consultants, and contractors. The Company also implemented a restructuring plan to better align its workforce with the needs of its business. The restructuring plan led to an approximately 10% reduction of the Company’s workforce on an FTE basis.

Note 15 - Subsequent Events

12 Months Ended

Dec. 31, 2024

NOTE 15. Subsequent Events

Appointment of Mr. Kevin Finney to Board of Directors

On January 24, 2025, following a recommendation by the Nominating and Governance Committee of the Board of Directors, the Company's Board appointed Kevin Finney to serve on the Board, effective January 28, 2025, until Mr. Kevin Finney’s successor is elected and qualified, or sooner in the event of his death, resignation, or removal. The Board has determined that Mr. Kevin Finney meets the requirements for independence under the applicable listing standards of The Nasdaq Stock Market LLC and the Securities Exchange Act of 1934, as amended. Mr. Kevin Finney was also appointed as a member of the Audit Committee and the Nominating and Governance Committee of the Board.

Modification of 2024 ATI-RRPV Contract

On February 7, 2025, the Company entered into Modification No. 5 (the “Modification”) to the ATI-RRPV Project Award Agreement No. 001, dated June 13, 2024 (the “Project Agreement”), with Advanced Technology International, the Rapid Response Partnership Vehicle’s Consortium Management Firm funded by BARDA of the U.S. Department of Health and Human Services. As previously disclosed, pursuant to the Project Agreement, the Company received funding to conduct a Phase 2b comparative study (the “Trial”) evaluating the Company’s oral pill COVID-19 vaccine candidate against an mRNA vaccine comparator approved by the U.S. Food and Drug Administration. The Company previously announced that it had completed enrollment of the sentinel cohort portion of the study comprising approximately 400 patients comparing its oral pill XBB candidate against an mRNA XBB comparator and an independent data safety monitoring board recommended the study to proceed without modifications based on initial safety assessment of 30-day data from the sentinel cohort.

The Modification increased the total amount of funding currently allotted to the Trial and available for payment to approximately $240.1 million, representing an increase of approximately $105.9 million. The Modification also clarifies the design of the Trial by specifying that the next portion of the Trial will compare the efficacy and safety of the Company’s KP.2 oral vaccine candidate against an mRNA comparator directed against KP.2 and will be comprised of 10,000 participants. The Company is awaiting approval from BARDA to commence dosing in the 10,000-participant portion of the Trial.

Stop Work Order Received for the 2024 ATI-RRPV Contract

On February 21, 2025, the Company received written notification from ATI in the form of stop work orders (the “Notices”) directing the Company to stop work on all of the Company’s efforts with respect to the Project Agreement with ATI, the Rapid Response Partnership Vehicle’s Consortium Management Firm funded by HHS BARDA, with the exception that the Company may continue efforts associated with the per protocol follow-up for the 400-person cohort.

The Notices stated that the stop work order is in effect for a period of 90 days after the date of the Notices and, that within a period of 90 days, ATI, as directed by the government, will either cancel the stop-work order, extend the stop work, or terminate the work covered by the letter as provided in Article 13.4 of the Project Agreement.

Reduction in Operating Costs

In the first quarter of 2025, the Company suspended all activities related to the 10,000-participant cohort of its COVID-19 Phase 2b study and implemented additional measures to reduce expenses with specific vendors, consultants, and contractors. The Company also implemented a restructuring plan to better align its workforce with the needs of its business. The restructuring plan led to an approximately 10% reduction of the Company’s workforce on an FTE basis.