Supplemental Balance Sheet Information Related to Operating Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets in other assets	$ 11,021	$ 11,760
Operating lease liabilities in other current liabilities	3,683	3,671
Operating lease liabilities in other long-term liabilities	7,807	8,549
Total operating lease liabilities	$ 11,490	$ 12,220