| Segment Reporting [Table Text Block] |
| | | Three Months Ended March 31, | |
| | | 2026 | | | 2025 | |
| Revenue | | $ | 39,227 | | | $ | 20,876 | |
| Less: | | | | | | | | |
| Research and development | | | | | | | | |
| External program costs: | | | | | | | | |
| Norovirus program | | | 48 | | | | 1,556 | |
| COVID-19 program | | | 20,393 | | | | 15,718 | |
| Other programs | | | — | | | | 306 | |
| Preclinical research | | | 81 | | | | 399 | |
| Process Development | | | — | | | | 46 | |
| Internal research and development costs | | | 8,891 | | | | 12,719 | |
| General and administrative | | | 4,641 | | | | 5,067 | |
| Interest income | | | (551 | ) | | | (437 | ) |
| Non-cash interest expense related to sale of future royalties | | | 505 | | | | 997 | |
| Other segment items(A) | | | 11 | | | | 1 | |
| Provision for income taxes | | | 29 | | | | 95 | |
| Segment net income (loss) | | $ | 5,179 | | | $ | (15,591 | ) |
| Reconciliation of net income (loss) | | | | | | | | |
| Adjustments and reconciling items | | | — | | | | — | |
| Net income (loss) | | $ | 5,179 | | | $ | (15,591 | ) |
|
| | | Year Ended December 31, | |
| | | 2025 | | | 2024 | |
| Revenue | | $ | 237,258 | | | $ | 28,700 | |
| Less: | | | | | | | | |
| Research and development | | | | | | | | |
| External program costs: | | | | | | | | |
| Norovirus program | | | 3,638 | | | | 3,178 | |
| COVID-19 program | | | 155,049 | | | | 16,883 | |
| Other programs | | | 345 | | | | 32 | |
| Preclinical research | | | 767 | | | | 1,909 | |
| Process Development | | | 46 | | | | 271 | |
| Internal research and development costs | | | 41,731 | | | | 51,940 | |
| General and administrative | | | 17,608 | | | | 20,780 | |
| Interest income | | | (1,596 | ) | | | (2,543 | ) |
| Non-cash interest expense related to sale of future royalties | | | 2,823 | | | | 2,969 | |
| Other segment items(A) | | | 44 | | | | (31 | ) |
| Provision for income taxes | | | 476 | | | | 260 | |
| Segment net income (loss) | | $ | 16,327 | | | $ | (66,948 | ) |
| Reconciliation of net income (loss) | | | | | | | | |
| Adjustments and reconciling items | | | — | | | | — | |
| Net income (loss) | | $ | 16,327 | | | $ | (66,948 | ) |
|