Net loss per share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net loss	$ (49,898)	$ (28,347)	$ (131,565)	$ (82,739)
Denominator:
Weighted average ordinary shares outstanding, basic	39,576,467	29,676,021	33,291,701	29,643,502
Weighted average ordinary shares outstanding, diluted	39,576,467	29,676,021	33,291,701	29,643,502
Net loss per share, basic	$ (1.26)	$ (0.96)	$ (3.95)	$ (2.79)
Net loss per share, diluted	$ (1.26)	$ (0.96)	$ (3.95)	$ (2.79)