Summary of significant accounting policies - Preferred stock right liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financial assets
January 1, 2023	$ 4,189
Fair value recognized upon entering into Securities Purchase Agreement		$ 6,940
Fair value adjustment	(6,011)	$ 3,430
December 31, 2023	10,200
Level 3
Financial assets
January 1, 2023	4,189
Fair value adjustment	6,011
December 31, 2023	$ 10,200