Stockholders' equity - Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to purchase common stock (in shares)	10,728,915	20,342,259
Total shares of common stock reserved (in shares)	18,289,709	34,559,618
Stock Appreciation Rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, outstanding (in shares)	82,791	106,155
2021 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for future issuance (in shares)	5,287,548	11,417,359
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for future issuance (in shares)	2,273,246	2,800,000

Aggregate number of common shares reserved for future issuance.

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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Number of options outstanding, including both vested and non-vested options.

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