Commitments and Contingencies - Schedule of Rent Expense Under Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 1,510	$ 1,338	$ 1,628

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration