Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total Stock-based compensation expenses	$ 39,378	$ 29,220	$ 20,939
Cost of revenues
Total Stock-based compensation expenses	6,427	4,773	3,729
Sales and marketing
Total Stock-based compensation expenses	7,740	5,837	3,243
Research and development
Total Stock-based compensation expenses	9,864	6,852	4,464
General and administrative
Total Stock-based compensation expenses	$ 15,347	$ 11,758	$ 9,503