Stock-Based Compensation (Details) - USD ($) $ / shares in Units, shares in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)	5.5
Common stock par value (in dollars per share)	$ 0.0005		$ 0.0005
Total share-based compensation cost not yet recognized	$ 109,200,000
Total compensation cost not yet recognized, period for recognition	2 years 8 months 12 days
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan, stock purchases as percentage of employee compensation maximum	10.00%
Maximum share value authorized for purchase under employee stock purchase plan	$ 23,750
Exercisable price percentage of closing price of another class of stock	95.00%
Maximum number of shares that may be purchased by eligible participants (in shares)	0.9
Proceeds from stock plans	$ 5,700,000	$ 4,700,000