Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of Inventories
Raw materials and subassemblies	$ 40,440	$ 45,829
Work-in-process	8,306	8,294
Finished goods	33,745	29,059
Reserve for excess and obsolete inventories	(12,989)	(13,037)
Total	$ 69,502	$ 70,145