Nature of the business and basis of presentation - Liquidity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Nature of the business and basis of presentation
Cash and cash equivalents	$ 372,769				$ 372,769		$ 438,680
Net loss	26,828	$ 27,564	$ 17,913	$ 16,191	54,392	$ 34,104
Accumulated deficit	$ 272,771				$ 272,771		$ 218,379