Collaborative Agreements (Details) (USD $)	3 Months Ended		6 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Apr. 30, 2010 Takeda Agreement	Jun. 30, 2012 Takeda Agreement item	Jun. 30, 2012 Takeda Agreement item	Dec. 31, 2010 Takeda Agreement	Jun. 30, 2012 Takeda Agreement Canada	Jun. 30, 2012 Takeda Agreement Canada	Jun. 30, 2012 3SBio License Agreement	Dec. 31, 2008 3SBio License Agreement
Collaborative Agreements
Upfront payment received					$ 60,000,000							$ 1,000,000
Milestone payments earned under the agreement						15,000,000	15,000,000
Milestone payments potentially receivable under the agreement						205,000,000	205,000,000
Maximum aggregate payment upon regulatory approval and commercial launch						18,000,000	18,000,000
Number of deliverables						4	4
Period of recognition of deferred revenues							10 years				13 years
Deferred revenue recognized in earnings related to upfront payment						1,500,000	3,000,000
Other reimbursement revenues						100,000	300,000	1,000,000
Initial term of license												13 years
Product sales, net	$ 14,420,000	$ 13,081,000	$ 28,128,000	$ 24,103,000					$ 200,000	$ 200,000
Maximum percentage of royalties receivable											25.00%