Segment information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) Segment	Dec. 31, 2024 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | Segment	1
Number of reportable segments | Segment	1
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 consolidated statements of operations and comprehensive loss as net loss. The measure of segment assets is reported on the 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.
Collaboration revenue	$ 6,941	$ 9,041
Less:
In-process research and development	(10,000)	(152,344)
General and administrative	(43,768)	(32,955)
Total operating expenses	(231,054)	(314,841)
Loss from operations	(224,113)	(305,800)
Interest income	11,719	12,837
Net loss	(212,394)	(292,963)
Single reportable segment
Segment Reporting Information [Line Items]
Collaboration revenue	6,941	9,041
Less:
In-process research and development	(10,000)	(152,344)
Other direct research and development	(43,233)	(26,803)
Indirect research and development	(51,413)	(31,074)
General and administrative	(29,064)	(21,862)
Other segment expenses	(28,156)	(17,315)
Total operating expenses	(231,054)	(314,841)
Loss from operations	(224,113)	(305,800)
Interest income	11,719	12,837
Net loss	(212,394)	(292,963)
Single reportable segment | Varegacestat
Less:
Direct research and development expenses	(52,359)	(27,954)
Single reportable segment | IM-3050
Less:
In house research and development expenses	(11,028)	(24,130)
Single reportable segment | IM-3050
Less:
In house research and development expenses	$ (5,801)	$ (13,359)