v3.26.1
Commitments and contingencies - Operating Leases and Finance Leases (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Dec. 31, 2025
Dec. 31, 2021
Dec. 31, 2025
Jun. 30, 2026
Jan. 31, 2023
Leases          
Finance lease right-of-use assets $ 800   $ 800 $ 700  
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Property, Plant and Equipment, Net   Property, Plant and Equipment, Net Property, Plant and Equipment, Net  
Finance lease liabilities $ 900   $ 900 $ 762  
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Accrued Liabilities, Current, Other Liabilities, Noncurrent   Accrued Liabilities, Current, Other Liabilities, Noncurrent Accrued Liabilities, Current, Other Liabilities, Noncurrent  
Finance lease not yet commenced       2 years  
Finance lease not yet commenced, contractual payments commitment       $ 5,200  
Office and laboratory space in Cambridge Massachusetts          
Leases          
Leases, term of contract         3 years
New Office and laboratory space in Cambridge, United Kingdom          
Leases          
Lease total contractual Term   10 years      
Leases, term of contract 5 years 5 years 5 years    
Rent-free period 9 months        
Renewal term 10 years   10 years    
Non-cash impact to operating lease right-of-use assets and operating lease liabilities     $ 12,400