Stock-based compensation - Restricted Stock - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restricted stock disclosures
Stock-based compensation.	$ 3,573	$ 2,558
Unvested restricted common stock units
Shares
Balance, beginning (in shares)	1,370,897
Granted (in shares)	696,908
Vested (in shares)	(324,520)
Forfeited (in shares)	(23,947)
Balance, ending (in shares)	1,719,338
Weighted Average Grant Date Fair Value Per Share
Balance, beginning (in dollars per share)	$ 6.65
Granted (in dollars per share)	7.63
Vested (in dollars per share)	5.75
Forfeited (in dollars per share)	6.42
Balance, ending (in dollars per share)	$ 7.22
Restricted stock disclosures
Vesting period	3 years
Stock-based compensation.	$ 1,090	841
Unrecognized stock-based compensation expense	$ 10,900
Remaining weighted-average remaining vesting period	2 years 4 months 24 days
Share-based Payment Arrangement, Employee | Unvested restricted common stock units
Restricted stock disclosures
Stock-based compensation.	$ 1,100	$ 800