Stockholders' equity - Common Stock Reserved for Future Issuance (Details) - shares shares in Thousands	Dec. 31, 2023	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	8,098	6,689
Pre-funded Warrants
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	758	758
2021 Stock Option and Incentive Plan
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	871	1,621
2021 Employee Stock Purchase Plan
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	552	434
Options to purchase common stock
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	3,678	2,562
Restricted stock units
Subsidiary, Sale of Stock [Line Items]
Common stock reserved for future issuance (in shares)	2,239	1,314