Components of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment	$ 36,314	$ 34,089
Accumulated amortization and depreciation	(18,982)	(16,993)
Property and equipment, net	17,332	17,096
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	10,980	9,739
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	2,361	2,176
Developed software
Property, Plant and Equipment [Line Items]
Property and equipment	14,379	13,930
Purchased software
Property, Plant and Equipment [Line Items]
Property and equipment	2,129	2,124
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 6,465	$ 6,120