Other Current Liabilities - Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015
Other Liabilities Disclosure [Abstract]
Engineering project reserves	$ 1,817	$ 1,688
Environmental reserves	2,601	2,387
Accrued medical benefits cost	378	389
Accrued commissions	491	560
Other	734	914
Total	$ 6,021	$ 5,938