Collaboration and License Agreements - Collaboration Agreements with GSK (Details) $ in Thousands		3 Months Ended	12 Months Ended
	Feb. 08, 2023	Mar. 31, 2024 USD ($) pathogen	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2021 pathogen program
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			$ 68,556	$ 74,205	$ 86,180
Research and development			455,966	506,499	579,720
Total revenues			68,556	74,205	86,180
2021 GSK Collaboration
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Reimbursement of research and development expenses			0	0	2,200
Other revenue | 2021 GSK Collaboration
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of non-influenza target pathogens | pathogen		2
Total revenues		$ 51,700
Profit-sharing amount previously constrained, released
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			0	0	35,730
2020 GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development			$ 5,500	$ 7,700	$ 23,400
2020 GSK | Antibody Program | Amendment Number Three
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of development costs (as a percent)	72.50%
2021 GSK | Preliminary Collaboration Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of separate programs | program						3
2021 GSK | 2021 Collaboration Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of non-influenza target pathogens | pathogen						3