Segment information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($) Segment	Mar. 31, 2025 USD ($)
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 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.
Collaboration revenue	$ 0	$ 2,926
Less:
General and administrative	(12,950)	(10,690)
Total operating expenses	(59,331)	(47,562)
Loss from operations	(59,331)	(44,636)
Interest income	5,492	2,996
Net loss	(53,839)	(41,640)
Single reportable segment
Segment Reporting Information [Line Items]
Collaboration revenue		2,926
Less:
Other direct research and development	9,971	4,673
Indirect research and development	16,314	10,337
General and administrative	8,649	7,376
Other segment expenses	8,556	6,314
Total operating expenses	59,331	47,562
Loss from operations	(59,331)	(44,636)
Interest income	5,492	2,996
Net loss	(53,839)	(41,640)
Single reportable segment | Varegacestat
Less:
Direct research and development expenses	9,832	14,387
Single reportable segment | IM-1021
Less:
Direct research and development expenses	3,864	3,067
Single reportable segment | IM-3050
Less:
Direct research and development expenses	1,307	1,033
Single reportable segment | IM-1617
Less:
Direct research and development expenses	$ 838	$ 375