Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 6,593		$ 5,837
Accrued inventories in-transit	1,259		1,908
Accrued other miscellaneous expenses	1,616		3,003
Accrued compensation	5,074		7,526
Income taxes payable	1,135		1,281
Accrued warranty	2,677	$ 2,694	3,601	$ 3,110	$ 3,273	$ 3,934
Total	$ 18,354		$ 23,156