Stockholders' equity - Common stock for future issuance (Details) - shares	Dec. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Exercise of options to purchase common stock (in shares)	3,071,187	2,684,041
Exercise of warrants to purchase common stock (in shares)	9,433,584	9,433,584
Total (in shares)	12,504,771	12,117,625