CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 2,124	$ 2,005	$ 6,352	$ 5,699
Cost of revenue
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	94	28	334	85
Sales and marketing
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	140	66	446	122
Research and development
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	186	292	927	952
General and administrative
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 1,704	$ 1,619	$ 4,645	$ 4,540