License and collaboration agreements - Additional Information 1 (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Harvard College | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent | ||
| Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] | ||
| Estimated fair value of success payment liability | $ 1.3 | $ 1.4 |