Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands |
Dec. 31, 2019 |
Mar. 31, 2019 |
|---|---|---|
| Accrued expenses and other current liabilities. | ||
| Accrued research and development costs | $ 1,416 | $ 530 |
| Accrued compensation and benefits costs | 2,099 | 1,510 |
| Accrued professional fees | 697 | 464 |
| Deferred rent | 24 | |
| Other | 345 | 273 |
| Total | $ 4,557 | $ 2,801 |