Schedule of Geographic Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenue	$ 373,598	$ 364,706	$ 316,910
Percentage of Total	100.00%	100.00%	100.00%
UNITED STATES
Segment Reporting Information [Line Items]
Revenue	$ 154,825	$ 140,973	$ 107,892
Percentage of Total	41.40%	38.70%	34.00%
GERMANY
Segment Reporting Information [Line Items]
Revenue	$ 54,743	$ 59,029	$ 56,287
Percentage of Total	14.70%	16.20%	17.80%
Rest Of Europe
Segment Reporting Information [Line Items]
Revenue	$ 48,277	$ 54,308	$ 45,698
Percentage of Total	12.90%	14.90%	14.40%
CHINA
Segment Reporting Information [Line Items]
Revenue	$ 38,491	$ 40,792	$ 37,651
Percentage of Total	10.30%	11.20%	11.90%
Rest of Asia-Pacific
Segment Reporting Information [Line Items]
Revenue	$ 62,467	$ 58,830	$ 57,802
Percentage of Total	16.70%	16.10%	18.20%
Other Countries
Segment Reporting Information [Line Items]
Revenue	$ 14,795	$ 10,774	$ 11,580
Percentage of Total	4.00%	2.90%	3.70%