Inventories - Inventories (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Inventory Disclosure [Abstract]
Finished goods	$ 735	$ 1,024
Work in process	7,564	7,350
Purchased and manufactured parts	16,162	12,532
Inventories, gross	24,461	20,906
Reserve for slow moving and obsolescence	(3,610)	(3,116)
Total	$ 20,851	$ 17,790