Balance Sheet Related Information (Details 2) (Inventory Valuation Reserve [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Inventory Valuation Reserve [Member]
Inventory valuation reserve
Balance at the beginning of the year	$ 2,730	$ 2,136	$ 1,989
Charged to costs and expenses	2,126	4,001	917
Disposals and currency translation adjustments	(2,705)	(3,407)	(770)
Balance at the end of the year	$ 2,151	$ 2,730	$ 2,136