Collaboration and license agreements - Summarizes the transaction price allocated to performance obligations (Details) - 2025 Novartis License Agreement - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total unearned amount of transaction price	$ 172,546	$ 178,247
License and research services for named immunology target [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total unearned amount of transaction price	6,558	7,019
Research services to support immunology license options [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total unearned amount of transaction price	80,458	85,698
Material right - first immunology license option [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total unearned amount of transaction price	49,091	49,091
Material right - second immunology license option [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total unearned amount of transaction price	$ 36,439	$ 36,439