Summary of significant accounting policies - Potentially dilutive securities (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Potentially dilutive securities
Total shares of common stock equivalents	612,225	595,248
Convertible preferred stock (as converted)
Potentially dilutive securities
Total shares of common stock equivalents	28,112	147,481
Options to purchase common stock
Potentially dilutive securities
Total shares of common stock equivalents	558,141	447,767
Unvested restricted stock units
Potentially dilutive securities
Total shares of common stock equivalents	25,972