Inventories - Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015
Inventory Disclosure [Abstract]
Finished goods	$ 1,342	$ 1,040
Work in process	9,896	7,515
Purchased and manufactured parts	17,626	13,418
Inventories, gross	28,864	21,973
Reserve for slow moving and obsolescence	(2,765)	(2,546)
Total	$ 26,099	$ 19,427