Segment Information and Information about Geographic Area (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments (in segment) | segment									1
Revenues	$ 52,224	$ 50,987	$ 48,466	$ 46,248	$ 44,445	$ 42,469	$ 39,877	$ 37,493	$ 197,925	$ 164,284	$ 133,579
Property and equipment, net	39,401				31,329				39,401	31,329
United States
Segment Reporting Information [Line Items]
Revenues									139,743	115,384	93,425
Property and equipment, net	30,733				25,623				30,733	25,623
Foreign
Segment Reporting Information [Line Items]
Revenues									58,182	48,900	$ 40,154
Property and equipment, net	$ 8,668				$ 5,706				$ 8,668	$ 5,706