Summary Of Significant Accounting Policies (Estimated Useful Lives Of Property And Equipment) (Detail)	12 Months Ended
	Dec. 31, 2012
Furniture And Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life, years	3 years
Furniture And Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life, years	5 years
Computer Equipment And Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life, years	3 years
Computer Equipment And Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life, years	5 years
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life, years	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Estimated Useful Life	Lesser of estimated useful life or life of lease