CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 4,981	$ 2,124	$ 12,325	$ 6,352
Cost of revenue
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	474	94	1,189	334
Sales and marketing
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	561	140	1,456	446
Research and development
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	349	186	929	927
General and administrative
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 3,597	$ 1,704	$ 8,751	$ 4,645