Stock-based compensation - Fair Value Assumptions (Details) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2024 |
Sep. 30, 2023 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] | ||||
| Risk-free interest rate | 4.40% | 4.40% | 4.00% | 3.80% |
| Expected dividend yield | 0.00% | 0.00% | 0.00% | 0.00% |
| Expected term (years) | 5 years | 6 years 1 month 2 days | 5 years 11 months 23 days | 6 years 21 days |
| Expected stock price volatility | 118.00% | 113.00% | 116.00% | 103.00% |