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v3.21.2

Fair value of financial assets and liabilities - Weighted Average of the Unobservable Inputs Used to Fair Value (Details) - Level 3 | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 Y $ / shares | Sep. 30, 2020 Y $ / shares | Sep. 30, 2021 Y $ / shares | Sep. 30, 2020 Y $ / shares
Remaining contractual term (in years) |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Preferred stock warrant liability, measurement input | Y | 6.6 | 7.4 | 6.8 | 7.7
Risk-free interest rate |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Preferred stock warrant liability, measurement input | 0.010 | 0.006 | 0.012 | 0.006
Expected volatility |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Preferred stock warrant liability, measurement input | 0.422 | 0.403 | 0.420 | 0.393
Series A1 Redeemable Convertible Preferred Stock |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Fair value of preferred stock warrant liability | $ 4.00 | $ 0.39 | $ 3.01 | $ 0.45
Series B1 Redeemable Convertible Preferred Stock |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Fair value of preferred stock warrant liability | 4.00 | 1.17 | 3.26 | 1.13
Series C1 Redeemable Convertible Preferred Stock |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |
Fair value of preferred stock warrant liability | $ 4.00 | $ 1.15 | $ 3.30 | $ 1.15

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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