Collaborative Agreements (Details) (USD $)	3 Months Ended			1 Months Ended			12 Months Ended					12 Months Ended
	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2013	Jun. 30, 2012 Takeda	Apr. 30, 2010 Takeda	Mar. 31, 2010 Takeda	Dec. 31, 2013 Takeda item	Dec. 31, 2012 Takeda	Dec. 31, 2011 Takeda	Dec. 31, 2010 Takeda	Dec. 31, 2013 Takeda Maximum	Dec. 31, 2008 3SBio License Agreement
Collaborative Agreements
Number of deliverables							4
Upfront payment received					$ 60,000,000							$ 1,000,000
Additional upfront payment										1,000,000
Period of recognition of deferred revenues						10 years
Milestone payments expected to be received under the agreement											186,000,000
Milestone payments revenue recognized under the agreement	5,000,000	15,000,000		15,000,000
Milestone revenue received								18,000,000
Deferred revenue recognized in earnings related to upfront payments and an $18.0 million milestone payment							7,900,000
Other reimbursement revenues							500,000	400,000	2,000,000
Product sales and royalty revenue recognized							500,000
Deferred revenues							2,400,000
Deferred revenues, short-term	9,104,000		8,226,000				300,000
Deferred revenues, long-term	50,350,000		44,534,000				2,100,000
Deferred costs							2,300,000
Deferred costs, short-term							300,000
Deferred costs, long-term							$ 2,000,000