Collaboration and License Agreements with Merck & Co., Inc. (Detail) (USD $)	12 Months Ended		1 Months Ended	4 Months Ended	35 Months Ended	8 Months Ended	20 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jul. 31, 2007 Collaborative Arrangement [Member]	May 04, 2010 Collaborative Arrangement [Member]	May 04, 2010 Collaborative Arrangement [Member]	Dec. 31, 2010 License Agreement Terms [Member]	Dec. 31, 2011 License Agreement Terms [Member]	Dec. 31, 2011 License Agreement Terms [Member] Sarcoma [Member]	Dec. 31, 2011 License Agreement Terms [Member] Other Cancer [Member]	Dec. 31, 2011 License Agreement Terms [Member] UNITED STATES Sarcoma [Member]	Dec. 31, 2011 License Agreement Terms [Member] European Union [Member] Sarcoma [Member]	Dec. 31, 2011 License Agreement Terms [Member] JAPAN Sarcoma [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of global development costs funded by each party in collaboration					50.00%
Proceeds from collaborators			$ 75,000,000	$ 12,800,000	$ 53,500,000
Percentage of costs funded in the license agreement							100.00%
Percentage of co-promotion by the company, maximum							20.00%
Proceeds from license fees						50,000,000
Potential milestone payments associated with the achievement of certain regulatory and sales objectives							514,000,000
Potential additional milestone payments associated with the achievement of certain sales thresholds							200,000,000
Proceeds from regulatory or sales milestone payments								25,000,000
Potential additional milestone payments associated with potential regulatory approvals								40,000,000	249,000,000	25,000,000	10,000,000	5,000,000
Recognition of deferred revenue		111,500,000
Service revenue	$ 111,000	$ 4,520,000