Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Summary of Inventories
Raw materials and purchased subassemblies	$ 49,421	$ 45,829
Work-in-process	8,613	8,294
Finished goods	26,880	29,059
Reserve for excess and obsolete inventories	(14,239)	(13,037)
Total	$ 70,675	$ 70,145