Segment Information and Information about Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 segment	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Number of operating segments			1
Revenues	$ 34,348	$ 27,749	$ 97,006	$ 78,923
Property and equipment, net	24,776		24,776		23,075
United States
Segment Reporting Information [Line Items]
Revenues	24,038	19,352	67,948	55,159
Property and equipment, net	22,013		22,013		19,909
Other
Segment Reporting Information [Line Items]
Revenues	10,310	8,397	29,058	23,764
Property and equipment, net	$ 2,763		$ 2,763		$ 3,166