Consolidated Statements Of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Operations [Abstract]
Collaboration revenue	$ 36,825	$ 14,709
Operating expenses:
Research and development	20,030	17,618
Selling, general and administrative	15,687	6,156
Total operating expenses	35,717	23,774
Income (loss) from operations	1,108	(9,065)
Other income (expense):
Interest expense	(585)
Interest income	27	41
Other expense	(98)	(333)
Total other income (expense), net	(656)	(292)
Net income (loss) before income tax expense (benefit)	452	(9,357)
Income tax expense (benefit)	12	(905)
Net income (loss)	$ 440	$ (8,452)
Basic earnings (loss) per common share	$ 0.01	$ (0.24)
Diluted earnings (loss) per common share	$ 0.01	$ (0.24)
Weighted-average common shares used in the calculation of basic earnings (loss) per common share	35,953,664	34,662,648
Weighted-average common shares used in the calculation of diluted earnings (loss) per common share	38,649,733	34,662,648