Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Line Items]
Estimated useful life of amortizable intangible assets	9 years 3 months 18 days	9 years 3 months 18 days
Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of amortizable intangible assets	3 years
Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of amortizable intangible assets	15 years