Summary of significant accounting policies - Net loss per share (Details) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Potentially dilutive securities
Total shares of common stock equivalents	11,904,984	5,328,809
Convertible preferred stock
Potentially dilutive securities
Total shares of common stock equivalents	2,949,630
Options to purchase common stock
Potentially dilutive securities
Total shares of common stock equivalents	8,955,354	4,821,759
Restricted stock units
Potentially dilutive securities
Total shares of common stock equivalents		507,050