Net loss per share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss	$ (26,828)	$ (17,913)	$ (54,392)	$ (34,104)
Denominator:
Weighted average ordinary shares outstanding, basic	29,648,564	24,052,168	29,626,974	23,047,745
Weighted average ordinary shares outstanding, diluted	29,648,564	24,052,168	29,626,974	23,047,745
Net loss per share, basic	$ (0.90)	$ (0.74)	$ (1.84)	$ (1.48)
Net loss per share, diluted	$ (0.90)	$ (0.74)	$ (1.84)	$ (1.48)