Collaboration Agreements (Tables)

12 Months Ended

Dec. 31, 2011

Collaboration Agreements [Abstract]

Deferred Revenue

	December 31,
	2011		2010
Current portion:
Deferred revenue from Astellas	$	23,747	$	23,138
Deferred revenue from Pfizer		36,015		36,015
Total	$	59,762	$	59,153
Long-term portion:
Deferred revenue from Astellas	$	47,494	$	69,477
Deferred revenue from Pfizer		36,015		72,030
Total	$	83,509	$	141,507

Schedule Of Collaboration Revenue

	Years Ended December 31,
	2011		2010		2009
Collaboration revenue from Astellas	$	24,374	$	23,492	$	3,893
Collaboration revenue from Pfizer		36,015		39,016		65,361
Total	$	60,389	$	62,508	$	69,254

Development And Commercialization Cost-Sharing Payments Receivable

	Years Ended December 31,
	2011		2010		2009
Development cost-sharing payments from Astellas	$	44,285	$	34,125	$	2,784
Development cost-sharing payments from Pfizer		12,365		29,139		20,435
Total	$	56,650	$	63,264	$	23,219

	Years Ended December 31,
	2011			2010			2009
Commercialization cost-sharing payments (to) from Astellas	$	(472	)	$	520		$	74
Commercialization cost-sharing payments from (to) Pfizer		32			(1,084	)		(720	)
Total	$	(440	)	$	(564	)	$	(646	)