Summary of Allowance for Doubtful Accounts Receivable (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Receivables [Abstract]
Balance at beginning of year	$ 1,202	$ 1,040	$ 320
Additions (recoveries)	127	487	720
Write-offs	(301)	(325)
Balance at end of year	$ 774	$ 1,202	$ 1,040