Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued expenses and other current liabilities
Accrued employee compensation and benefits	$ 5,545	$ 13,394
Accrued external research and development expenses	13,845	11,839
Accrued professional fees	1,493	1,143
Current portion of operating lease liabilities	$ 4,974	$ 4,876
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Other	$ 172	$ 257
Accrued expenses and other current liabilities	$ 26,029	$ 31,509