Summary of Estimated Useful Lives of Plant and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
Lab Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	5 years
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	5 years
Software and Computer Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	3 years
Software and Computer Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	Lesser of the useful life or the term of the respective lease
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	Not depreciated
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	30 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	Not depreciated until put into service