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License and Collaboration Agreements (Details) (USD $)	3 Months Ended		6 Months Ended		1 Months Ended	3 Months Ended		6 Months Ended			18 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended		1 Months Ended		3 Months Ended
License and Collaboration Agreements (Details) (USD $)	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Nov. 30, 2009 License and Collaboration Agreements Sanofi	Jun. 30, 2012 License and Collaboration Agreements Sanofi	Jun. 30, 2011 License and Collaboration Agreements Sanofi	Jun. 30, 2012 License and Collaboration Agreements Sanofi	Jun. 30, 2011 License and Collaboration Agreements Sanofi	Dec. 31, 2011 License and Collaboration Agreements Sanofi	Dec. 31, 2011 License and Collaboration Agreements Sanofi Phase 2 clinical trials in breast cancer and non-small cell lung cancer	Mar. 31, 2012 License and Collaboration Agreements Sanofi Phase 2 clinical trial in ovarian cancer	May 31, 2011 License and Collaboration Agreements PharmaEngine	Jun. 30, 2012 License and Collaboration Agreements PharmaEngine	Jun. 30, 2011 License and Collaboration Agreements PharmaEngine	Jun. 30, 2012 License and Collaboration Agreements PharmaEngine	Jun. 30, 2011 License and Collaboration Agreements PharmaEngine	May 31, 2011 License and Collaboration Agreements PharmaEngine Development and regulatory milestone	May 31, 2011 License and Collaboration Agreements PharmaEngine Sales milestone	Mar. 31, 2012 License and Collaboration Agreements PharmaEngine Phase 3 clinical trial in pancreatic cancer
License and collaboration agreements
Upfront license fee received					$ 60,000,000
Milestone payments received											20,000,000	5,000,000
Expected development period from the effective date of agreement					12 years
Recognized revenue under collaboration agreements
Upfront payment						1,250,000	1,250,000	2,500,000	2,500,000
Milestone payment						521,000	209,000	1,933,000	417,000
Development services						9,160,000	4,687,000	17,302,000	9,392,000
Manufacturing services and other						1,106,000	439,000	1,627,000	694,000
Total						12,037,000	6,585,000	23,362,000	13,003,000
Assets and liabilities related to collaboration agreement
Accounts receivable, billed						2,013,000		2,013,000		4,478,000
Accounts receivable, unbilled						4,909,000		4,909,000		2,925,000
Deferred revenue						85,057,000		85,057,000		84,466,000
Collaborative arrangement additional information
Upfront license feess paid													10,000,000		10,000,000
Maximum milestone payment obligation																		80,000,000	130,000,000
Milestone payment																				5,000,000
Research and development expenses	$ 28,758,000	$ 31,187,000	$ 60,409,000	$ 49,188,000										$ 300,000	$ 10,500,000	$ 5,600,000	$ 10,500,000