CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Issuance of shares of Common Stock upon exercise of stock options and restricted stock units	5,220,474	7,044,844	6,898,551
Issuance of shares of Common Stock under the ESPP	194,453	193,657	390,000
Issuance of shares of Common Stock for services rendered	2,017
Pfizer Notes Due 2014
Issuance of shares of Common Stock upon conversion of convertible senior notes and Pfizer Note			1,025,641
4.75% Convertible Senior Notes due 2015
Issuance of shares of Common Stock upon conversion of convertible senior notes and Pfizer Note	10,352,784	653,438	21,208,303
Aggregate principal amount of notes repurchased			$ 117.3
Interest rate of debt (as a percent)	4.75%	4.75%	4.75%
0.375% Convertible Senior Notes due 2018
Interest rate of debt (as a percent)	0.375%	0.375%	0.375%
1.25% Convertible Senior Notes due 2020
Issuance of shares of Common Stock upon conversion of convertible senior notes and Pfizer Note	3,902
Interest rate of debt (as a percent)	1.25%	1.25%	1.25%