Royalty Revenue from Stivarga (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Revenue from Collaboration Agreement
Royalty revenue	$ 10,161,000	$ 19,338,000
Bayer
Revenue from Collaboration Agreement
Fee earned for fee-for-service arrangement	2,100,000	3,700,000
Bayer | Stivarga
Revenue from Collaboration Agreement
Royalty revenue	10,200,000	19,300,000
Royalty payment percentage		20.00%
Obligation to pay past or future development and commercialization costs	$ 0	$ 0