Property and Equipment - Estimated Useful Life of the Related Asset (Detail)	12 Months Ended
	Dec. 31, 2014
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Leasehold Improvements and Fixed Assets Under Financing Lease [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	shorter of estimated useful life or lease term
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Minimum [Member] | Lab and Facility Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum [Member] | Lab and Facility Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years