Accrued Expenses - Summary of Accrued Expenses (Detail) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Payables And Accruals [Abstract]
Marketing programs	$ 4,129,788	$ 2,688,818
Payroll and payroll related	9,365,205	7,970,443
Professional fees	1,200,143	1,711,926
Other accrued expenses	4,125,679	4,285,614
Total accrued expenses	$ 18,820,815	$ 16,656,801