Revenue Recognition - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Royalty revenue	$ 3,981,059	$ 2,889,458	$ 11,327,500	$ 8,940,648
Percentage of royalty revenue, remittance to the University of Michigan			15.00%
Cost of royalty and other revenue	594,406	418,419	1,593,427	1,211,180
Revenue from sponsored research and development projects	18,000	100,000	704,000	866,000
Bristol Myers Squibb Company
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Royalty revenue	3,963,000	2,789,000	10,623,000	8,075,000
Cost of royalty and other revenue	$ 594,000	$ 418,000	$ 1,593,000	$ 1,211,000