Segment information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2025 USD ($) segment	Mar. 31, 2024 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	1
Number of reportable segments | segment	1
Collaboration revenue	$ 2,926	$ 1,029
Less:
In-process research and development		(111,954)
General and administrative	(10,690)	(6,005)
Total operating expenses	(47,562)	(133,328)
Loss from operations	(44,636)	(132,299)
Interest income	2,996	2,807
Net loss	(41,640)	(129,492)
Single reportable segment
Segment Reporting Information [Line Items]
Collaboration revenue	2,926	1,029
Less:
In-process research and development		(111,954)
Other product candidates	(6,843)	(6,295)
Indirect research and development	(11,542)	(4,128)
General and administrative	(10,690)	(6,005)
Total operating expenses	47,562	133,328
Loss from operations	(44,636)	(132,299)
Interest income	2,996	2,807
Net loss	(41,640)	(129,492)
Single reportable segment | Varegacestat
Less:
Direct research and development expenses	(14,387)	(250)
Single reportable segment | IM-1021
Less:
Direct research and development expenses	(3,067)	(2,724)
Single reportable segment | IM-3050
Less:
Direct research and development expenses	$ (1,033)	$ (1,972)