Stock-based compensation - Summary of Service-based Stock Option Activity and Related Information (Details) - USD ($)
$ / shares in Units, $ in Thousands |
3 Months Ended |
12 Months Ended |
Mar. 31, 2019 |
Mar. 31, 2020 |
| Options outstanding |
|
|
| Exercised (in shares) |
(62,450)
|
|
| Weighted-average exercise price |
|
|
| Exercised (in USD per share) |
$ 1.84
|
|
| Closing stock price (in USD per share) |
|
$ 9.84
|
| Service-based Stock Options |
|
|
| Options outstanding |
|
|
| Beginning balance (in shares) |
2,746,670
|
2,575,579
|
| Granted (in shares) |
115,100
|
202,560
|
| Exercised (in shares) |
|
(334,572)
|
| Canceled or forfeited (in shares) |
(286,191)
|
(444,014)
|
| Ending balance (in shares) |
2,575,579
|
1,999,553
|
| Options outstanding, Exercisable (in shares) |
|
1,291,647
|
| Weighted-average exercise price |
|
|
| Beginning balance (in USD per share) |
$ 12.91
|
$ 12.24
|
| Granted (in USD per share) |
7.95
|
14.18
|
| Exercised (in USD per share) |
|
4.08
|
| Canceled or forfeited (in USD per share) |
16.98
|
15.07
|
| Ending balance (in USD per share) |
$ 12.24
|
13.17
|
| Weighted-average exercise price, Exercisable (in USD per share) |
|
$ 12.06
|
| Weighted-average remaining contractual life (in years), Outstanding |
6 years 10 months 24 days
|
6 years 9 months 7 days
|
| Weighted-average remaining contractual life (in years), Exercisable |
|
6 years 1 month 6 days
|
| Aggregate intrinsic values, Outstanding |
$ 6,958
|
$ 3,773
|
| Aggregate intrinsic values, Exercisable |
|
$ 3,469
|