Equity Award Plan Activities - Total Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 14,232	$ 11,208	$ 27,592	$ 20,047
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	868	784	1,661	1,420
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	7,595	6,379	15,052	11,307
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	3,780	2,865	7,427	5,274
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1,989	$ 1,180	$ 3,452	$ 2,046