Allowance for Doubtful Accounts (Detail) (USD $)	6 Months Ended
	Jun. 30, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 4,778,915
Provisions recognized as reduction in revenues	1,237,090
Write-offs, net of recoveries	(3,753,215)
Balance at end of period	$ 2,262,790