Depreciation Expense Computed Using Straight-Line Method over Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2013
Computer hardware | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	2 years
Computer hardware | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	3 years
Computer software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	2 years
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	5 years
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	5 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (in years)	5 years