Stock-based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	$ 5,103	$ 4,421	$ 15,122	$ 12,678
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized employee compensation cost	25,100		$ 25,100
Unrecognized employee compensation cost, period for recognition			2 years 10 months 24 days
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized employee compensation cost	9,200		$ 9,200
Unrecognized employee compensation cost, period for recognition			3 years 4 months 24 days
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	516	333	$ 1,318	1,005
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	1,585	1,294	4,373	3,584
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	821	1,015	3,459	2,806
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	$ 2,181	$ 1,779	$ 5,972	$ 5,283