Segment Information (Schedule Of Revenue From Unaffiliated Customers By Geographic Area) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 segment	Mar. 31, 2012 segment
Segment Reporting Information [Line Items]
Number of reportable segments	1	1
Revenue from unaffiliated customers	$ 102,079	$ 77,920
United States [Member]
Segment Reporting Information [Line Items]
Revenue from unaffiliated customers	57,153	45,909
Germany [Member]
Segment Reporting Information [Line Items]
Revenue from unaffiliated customers	11,911	7,423
Other Europe [Member]
Segment Reporting Information [Line Items]
Revenue from unaffiliated customers	16,669	13,288
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Revenue from unaffiliated customers	$ 16,346	$ 11,300