ALLIANCES AND COLLABORATIONS (Exelixis) (Details) (Exelixis [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
The Company's equity investment in a collaboration partner	1.00%
XL-281 [Member] | Development and Regulatory Milestones [Member]
The amount of terminated contingent milestone payments	$ 315
XL-281 [Member] | Sales-Based Milestones [Member]
The amount of terminated contingent milestone payments	$ 150