Segment Information (Revenues Attributable to Domestic and Foreign Operations) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Revenue		$ 59,334	$ 51,087	$ 119,104	$ 98,915
United States [Member]
Segment Reporting Information [Line Items]
Revenue		38,996	33,765	80,437	64,865
Other Americas [Member]
Segment Reporting Information [Line Items]
Revenue	[1]	3,145	2,172	5,848	4,321
Americas [Member]
Segment Reporting Information [Line Items]
Revenue		42,141	35,937	86,285	69,186
EMEA [Member]
Segment Reporting Information [Line Items]
Revenue	[2]	13,421	11,055	25,206	21,569
APAC [Member]
Segment Reporting Information [Line Items]
Revenue	[3]	$ 3,772	$ 4,095	$ 7,613	$ 8,160

[1] Canada, Latin America and South America

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

[3] Asia-Pacific (“APAC”)