Segment Information and Information about Geographic Area (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment									1
Revenues	$ 44,445	$ 42,469	$ 39,877	$ 37,493	$ 36,573	$ 34,348	$ 32,302	$ 30,356	$ 164,284	$ 133,579	$ 107,962
Property and equipment, net	31,329				26,618				31,329	26,618
United States
Segment Reporting Information [Line Items]
Revenues									115,384	93,425	75,485
Property and equipment, net	25,623				23,650				25,623	23,650
Foreign
Segment Reporting Information [Line Items]
Revenues									48,900	40,154	$ 32,477
Property and equipment, net	$ 5,706				$ 2,968				$ 5,706	$ 2,968