Summary of significant accounting policies - Narrative (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) segment	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)
Summary of significant accounting policies
Number of operating segments | segment	1
Restricted cash	$ 100,000		$ 100,000
Deferred offering costs	400,000		$ 300,000
Operating right-of-use asset, net	$ 190,000	$ 200,000
Operating lease liability		$ 200,000