Commitments and contingencies Commitments and contingencies - Future minimum lease payments (Details) $ in Thousands |
Dec. 31, 2019
USD ($)
|
|---|---|
| Lessee, Operating Lease, Liability, Payment, Due [Abstract] | |
| 2020 | $ 1,477 |
| 2021 | 1,473 |
| 2022 | 1,511 |
| 2023 | 1,548 |
| 2024 | 1,853 |
| Total lease payments | 7,862 |
| Less imputed interest | (1,500) |
| Total | 6,362 |
| Finance Lease, Liability, Payment, Due [Abstract] | |
| 2020 | 134 |
| 2021 | 23 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 and thereafter | 0 |
| Total lease payments | 157 |
| Less imputed interest | (7) |
| Total | 150 |
| Finance and Operating Lease, Liability, Payment, Due [Abstract] | |
| 2020 | 1,611 |
| 2021 | 1,496 |
| 2022 | 1,511 |
| 2023 | 1,548 |
| 2024 and thereafter | 1,853 |
| Total lease payments | 8,019 |
| Less imputed interest | 1,507 |
| Total | $ 6,512 |