Income taxes - Valuation allowance (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Income Tax Disclosure [Abstract] | ||
| Valuation allowance as of January 1, | $ (108,690) | $ (66,853) |
| Decreases recorded as a benefit to income tax provision | (68,371) | (41,837) |
| Valuation allowance as of December 31, | $ (177,061) | $ (108,690) |