Stock-based compensation (Tables)

6 Months Ended

Sep. 30, 2020

Stock-based Compensation

Summary of stock option activity

		Weighted		Weighted Average
	Number of	Average		Contractual Term	Aggregate
	Shares	Exercise Price		(Years)	Intrinsic Value
Outstanding as of March 31, 2020	4,964,381	$	9.78	8.02	$	15,344
Granted	2,081,504		12.52	9.57
Exercised	(165,268)		11.19
Cancelled	(215,271)		12.38
Outstanding as of September 30, 2020	6,665,346		10.52	8.14	$	83,329
Options exercisable as of March 31, 2020	2,117,721	$	5.66	7.20	$	11,733
Options exercisable as of September 30, 2020	3,894,669	$	12.82	7.02	$	43,583

Schedule of stock-based compensation expense

	Three Months Ended				Six Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Research and development	$	1,298	$	815	$	2,297	$	1,656
General and administrative		1,503		966		2,972		1,935
	$	2,801	$	1,781	$	5,269	$	3,591

Employees stock options

Stock-based Compensation

Schedule of assumptions used to determine the grant-date fair value of stock options granted

	Three Months Ended				Six Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Risk-free interest rate	0.33	%	1.68	%	1.08	%	2.30	%
Expected term (in years)	6.1		6.1		6.4		6.0
Expected volatility	75.3	%	70.2	%	74.6	%	71.4	%
Expected dividend yield	0	%	0	%	0	%	0	%