Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		111 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Collaboration revenue	$ 878	$ 20,837	$ 2,784	$ 22,232	$ 80,019
Operating expenses:
Research and development	7,855	6,725	26,590	25,552	277,722
Sales, general and administrative	5,642	5,890	19,950	15,529	104,924
Total operating expenses	13,497	12,615	46,540	41,081	382,646
Income (loss) from operations	(12,619)	8,222	(43,756)	(18,849)	(302,627)
Interest income		6	1	58	6,469
Interest expense		(43)		(316)	(7,309)
Other expense, net	(3)	(2)	(2)	(12)	(776)
Net income (loss)	(12,622)	8,183	(43,757)	(19,119)	(304,243)
Cumulative stock dividend attributed to preferred stockholders					(13,925)
Net income (loss) attributed to common stockholders	(12,622)	8,183	(43,757)	(19,119)	(318,168)
Net income (loss) per share attributed to common stockholders
Basic	$ (0.38)	$ 0.27	$ (1.39)	$ (0.63)
Diluted	$ (0.38)	$ 0.26	$ (1.39)	$ (0.63)
Weighted average shares outstanding used in calculating net income (loss) per share attributed to common stockholders
Basic	33,369	30,440	31,569	30,329
Diluted	33,369	31,611	31,569	30,329
Total comprehensive income (loss)	$ (12,622)	$ 8,183	$ (43,757)	$ (19,119)	$ (304,243)