Stock-based compensation - Summary of Activity for Options Vest Solely Based upon Satisfaction of Service Condition (Details) - Service-based Vesting Stock Options $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares
Options outstanding
Beginning balance (in shares) | shares	1,999,553
Exercised (in shares) | shares	(98,970)
Canceled or forfeited (in shares) | shares	(5,083)
Ending balance (in shares) | shares	1,895,500
Options outstanding, Exercisable (in shares) | shares	1,215,922
Weighted-average exercise price
Beginning balance (in USD per share) | $ / shares	$ 13.17
Exercised (in USD per share) | $ / shares	3.45
Canceled or forfeited (in USD per share) | $ / shares	21.61
Ending balance (in USD per share) | $ / shares	13.66
Weighted-average exercise price, Exercisable (in USD per share) | $ / shares	$ 12.77
Weighted-average remaining contractual life (in years), Outstanding	6 years 7 months 6 days
Weighted-average remaining contractual life (in years), Exercisable	6 years
Aggregate intrinsic values, Outstanding | $	$ 10,801
Aggregate intrinsic values, Exercisable | $	$ 8,077