CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 5,785	$ 4,754	$ 13,806	$ 11,146
Cost of revenue
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	116	101	271	154
Sales and marketing
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	535	308	1,174	376
Research and development
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	475	643	1,224	1,601
General and administrative
Includes stock-based compensation expense as follows:
Total stock-based compensation expense	$ 4,659	$ 3,702	$ 11,137	$ 9,015