Allowance for Doubtful Accounts (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Receivables [Line Items]
Balance, beginning of the year	$ 334,473	$ 30,000
Amounts provided	138,339	306,520	302,723
Amounts written off	(135,353)	(2,047)	(301,984)
Balance, end of the year	$ 337,459	$ 334,473	$ 30,000