CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenue:
Revenue from collaboration agreement	$ 70,744	$ 75,041	$ 215,479	$ 210,142
Product revenue	18,636		18,636
Royalty revenue	131		131
Total revenue	89,511	75,041	234,246	210,142
Operating expenses:
Cost of goods sold (excludes amortization of certain acquired intangible assets)	496		496
Research and development	85,667	58,532	242,683	184,071
Selling, general and administrative	61,747	42,642	149,598	115,349
Contingent consideration	9,843	5,945	66,235	23,195
Lease termination exit costs		130		10,857
Intangible asset amortization	4,110		4,110
Total operating expenses	161,863	107,249	463,122	333,472
Loss from operations	(72,352)	(32,208)	(228,876)	(123,330)
Investment income, net	625	435	2,002	1,728
Interest expense	(5,456)	(5,112)	(16,126)	(15,155)
Other income (expense)	(1,194)	25	2,365	(3,776)
Loss before provision (benefit) for income taxes	(78,377)	(36,860)	(240,635)	(140,533)
Provision (benefit) for income taxes	(95,773)		(95,769)	32
Net income (loss)	$ 17,396	$ (36,860)	$ (144,866)	$ (140,565)
Basic net income (loss) per share (in dollars per share)	$ 0.26	$ (0.58)	$ (2.25)	$ (2.22)
Diluted net income (loss) per share (in dollars per share)	$ 0.25	$ (0.58)	$ (2.25)	$ (2.22)
Shares used in computing basic net income (loss) per share (in shares)	65,831	63,555	64,362	63,328
Shares used in computing diluted net income (loss) per share (in shares)	68,463	63,555	64,362	63,328