Net loss per share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss	$ (27,564)	$ (16,191)
Denominator:
Weighted average ordinary shares outstanding, basic	29,605,143	22,100,840
Weighted average ordinary shares outstanding, diluted	29,605,143	22,100,840
Net loss per share, basic	$ (0.93)	$ (0.73)
Net loss per share, diluted	$ (0.93)	$ (0.73)