Short-term investments (Tables)

12 Months Ended

Mar. 31, 2020

Short-term investments

Schedule of short-term investments

	March 31, 2020
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	21,818	$	66	$	—	$	21,884
US Government agency bonds		15,217		78		—		15,295
US Treasury bonds		35,590		220		—		35,810
Corporate debt securities		36,107		24		(65)		36,066
	$	108,732	$	388	$	(65)	$	109,055

	March 31, 2019
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	46,687	$	2	$	(2)	$	46,687
US Government agency bonds		15,889		4		—		15,893
US Treasury bonds		38,047		13		—		38,060
Corporate debt securities		8,469		—		(2)		8,467
	$	109,092	$	19	$	(4)	$	109,107