Summary of significant accounting policies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($) Segment	Dec. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)
Summary of significant accounting policies
Number of operating segments	1
Number of reportable segments	1
Restricted cash | $	$ 210	$ 210	$ 100
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assesses performance for the segment based on net loss, which is reported on the condensed consolidated statements of operations and comprehensive loss as net loss. The measure of segment assets is reported on the condensed consolidated balance sheets as total assets. When evaluating the Company’s financial performance, the CODM regularly reviews total revenues, total expenses and research and development expenses by program.