Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Maximum maturity period for classification of investments as cash equivalents			3 months
Investments other-than-temporary losses			$ 0	$ 0
Contractual maturities accounts receivable			less than one year
Term for post-contract technical support			1 year
Contract loss provisions recorded	0	0	0	0
Term of agreement for revenue recognition			2 years
Depreciation and amortization	4,504,000	1,961,000	7,073,000	3,815,000
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	26,443,000		26,443,000		18,009,000
Restatement Adjustment [Member]
Property, Plant and Equipment [Line Items]
Employee compensation and benefit expense	2,900,000
Depreciation and amortization	1,300,000
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	$ 1,600,000		$ 1,600,000
Internally Developed Software [Member]
Property, Plant and Equipment [Line Items]
Estimated life of intangible assets			3 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of amortizable intangibles			3 years
Estimated life of intangible assets			3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of amortizable intangibles			7 years
Estimated life of intangible assets			15 years