Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014
Payables And Accruals [Abstract]
Accounts payable	$ 7,063	$ 1,749
Accrued inventories in-transit	1,330	212
Accrued miscellaneous expenses	4,424	6,076
Accrued outside services	3,026	3,716
Accrued subcontractor program costs	60	290
Accrued compensation	4,070	5,939
Income taxes payable	197	173
Accrued adverse purchase commitments	0	402
Accrued warranty	3,367	3,207
Total	$ 23,537	$ 21,764