Equipment and Improvements - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2013
Property, Plant and Equipment [Line Items]
Leasehold improvements amortization Description	Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the asset or the lease term.
Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of the asset	7 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of the asset	3 years