Stockholders' Deficit (Details 3) - Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares Available For Grant
Outstanding at the beginning of the period (in shares)	5,399,816
Options granted (in shares)	(1,900,855)
Options cancelled (in shares)	347,756
Outstanding at the end of the period (in shares)	3,846,717	5,399,816
Shares Subject to Outstanding Options, Shares
Outstanding at the beginning of the period (in shares)	14,655,043
Options granted (in shares)	1,900,855
Options exercised (in shares)	(5,155,863)
Options cancelled (in shares)	(347,756)
Outstanding at the end of the period (in shares)	11,052,279	14,655,043
Shares Subject to Outstanding Options, Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 21.96
Options granted (in dollars per share)	79.14
Options exercised (in dollars per share)	16.62
Options cancelled (in dollars per share)	45.52
Outstanding at the end of the period (in dollars per share)	$ 33.55	$ 21.96
Stock option, other disclosures
Options exercisable and vested (in shares)	8,239,929	10,486,757	12,474,199
Intrinsic value of options exercised	$ 416.3	$ 359.7	$ 141.8
Intrinsic value of options outstanding	828.9
Intrinsic value of vested options	$ 824.6