Segment Information (Revenues Attributable to Domestic and Foreign Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 59,770		$ 47,828
United States [Member]
Segment Reporting Information [Line Items]
Revenue	41,442		31,098
Other Americas [Member]
Segment Reporting Information [Line Items]
Revenue	2,703	[1]	2,150	[1]
Americas [Member]
Segment Reporting Information [Line Items]
Revenue	44,145		33,248
EMEA [Member]
Segment Reporting Information [Line Items]
Revenue	11,784	[2]	10,515	[2]
APAC [Member]
Segment Reporting Information [Line Items]
Revenue	$ 3,841	[3]	$ 4,065	[3]

[1] Canada, Latin America and South America

[2] Europe, the Middle East and Africa (“EMEA”)

[3] Asia-Pacific (“APAC”)