CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 3,597	$ 2,092
Cost of revenue
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	305	119
Sales and marketing
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	390	154
Research and development
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	273	242
General and administrative
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 2,629	$ 1,577