Agreements (Details 7) (Lilly, USD $)	12 Months Ended		1 Months Ended	12 Months Ended							12 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Sales milestones	Dec. 31, 2011 Right-to-test agreement	Jun. 30, 2012 Development and Commercialization License	Dec. 31, 2011 Development and Commercialization License	Dec. 31, 2011 Development and Commercialization License Maximum	Jun. 30, 2012 Development and Commercialization License Phase I clinical trial	Dec. 31, 2011 Development and Commercialization License Development milestones	Dec. 31, 2011 Development and Commercialization License Regulatory milestones	Dec. 31, 2011 Development and Commercialization License Sales milestones	Jun. 30, 2012 Future Technological Improvements	Jun. 30, 2012 Research Services
Collaborative Agreements disclosures
Term of agreement			3 years
Payments received under collaboration agreement			$ 20,000,000
Potential milestone payments receivable for the first license under agreement						200,500,000	5,000,000	30,500,000	70,000,000	100,000,000
License exercise fee, per subsequent license				2,000,000	2,000,000
Potential milestone payments receivable for each subsequent license under agreement						199,000,000		29,000,000
Allocation of fees to deliverables
Estimated utilization period after commercialization	10 years
Discount rate (as a percent)	16.00%
Total expected arrangement consideration	$ 28,200,000	$ 800,000		$ 23,500,000							$ 600,000	$ 3,300,000
Estimated term of development and commercialization license				25 years