Fair value measurements - Schedule of assets and liabilities measured at fair value (Details) - Fair value, recurring - USD ($) $ in Thousands |
Jan. 31, 2023 |
Jan. 31, 2022 |
|---|---|---|
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Money market mutual funds | $ 163,563 | $ 197,601 |
| Total assets | 163,563 | 197,601 |
| Quoted Prices in Active Markets for Identical Assets (Level 1) | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Money market mutual funds | 163,563 | 197,601 |
| Total assets | 163,563 | 197,601 |
| Significant Other Observable Inputs (Level 2) | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Money market mutual funds | 0 | 0 |
| Total assets | 0 | 0 |
| Significant Unobservable Inputs (Level 3) | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Money market mutual funds | 0 | 0 |
| Total assets | $ 0 | $ 0 |