Summary of significant accounting policies - Net loss per share (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Potentially dilutive securities
Total shares of common stock equivalents	9,989,871	5,118,834
Convertible preferred stock
Potentially dilutive securities
Total shares of common stock equivalents	128,597
Options to purchase common stock
Potentially dilutive securities
Total shares of common stock equivalents	9,606,504	4,719,115
Restricted stock units
Potentially dilutive securities
Total shares of common stock equivalents	254,770	399,719