Related party transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021
Related Party Transaction
Issuance of shares upon warrant exercise	$ 93
Affiliated Entity | Common Stock | Phoenix Venture Partners II, L.P
Related Party Transaction
Issuance of shares upon warrant exercise (in shares)		307,211
Class of warrant or right, exercise price of warrants or rights (usd per share)		$ 0.3027
Issuance of shares upon warrant exercise		$ 100