Property and Equipment (Details) - Property and equipment (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property and equipment [Abstract]
Computer equipment	$ 14,307,205	$ 14,210,373
Furniture and fixtures	2,726,959	2,740,089
Leasehold improvements	3,401,591	3,354,575
	20,435,755	20,305,037
Less accumulated depreciation and amortization	16,035,351	14,633,037
Property and equipment, net	$ 4,400,404	$ 5,672,000