Nature of the business (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Nature of the business
Accumulated deficit	$ 557,410	$ 515,770
Non-restricted cash and cash equivalents	257,613	143,351	$ 269,723
Marketable securities	$ 59,710	$ 73,952