Fair value of financial assets and liabilities - Roll forward of the warrant liability (Details) - Warrant liability $ in Thousands |
9 Months Ended |
|---|---|
|
Dec. 31, 2018
USD ($)
| |
| Roll forward of the warrant liability | |
| Balance at beginning of the period | $ 1,642 |
| Change in fair value | 5,452 |
| Conversion of convertible preferred stock warrant into common stock warrant | $ (7,094) |