Inventories, Net (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012	Jan. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 47,195	$ 45,723
Work in process	18,835	15,021
Finished goods	7,737	7,599
Total inventories	73,767	68,343
Less: reserve for excess and obsolete inventories	(23,669)	(23,938)
Inventories, net	$ 50,098	$ 44,405