Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Payables and Accruals [Abstract]
Accounts payable	$ 3,096	$ 3,207
Accrued inventories in-transit	1,207	313
Accrued other miscellaneous expenses	2,412	2,240
Accrued compensation	3,605	5,042
Income taxes payable	536	1,344
Accrued warranty	1,769	2,344	$ 3,601
Total	$ 12,625	$ 14,490