Share-based compensation - Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,892	$ 1,083	$ 10,278	$ 3,340
Unrecognized compensation cost	72,200		$ 72,200
Recognition period			3 years 6 months
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,820	466	$ 3,244	1,323
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3,072	$ 617	$ 7,034	$ 2,017