Accounts Receivable - net (Tables)

12 Months Ended

Dec. 31, 2012

Accounts Receivable - net

Schedule of accounts receivable - net

	December 31,			December 31,
	2012			2011
Trade receivables (note 8)	$	25,605,726		$	20,779,992
Allowance for doubtful accounts	(2,935,659		)	(3,927,914		)
	22,670,067			16,852,078
Other receivables	770,068			982,329
Total accounts receivable	$	23,440,135		$	17,834,407

Schedule of maximum exposure to credit risk at the balance sheet date relating to trade receivables

	December 31,		December 31,
	2012		2011
Aging within one year, net of allowance for doubtful accounts	$	22,065,143	$	16,025,464
Aging greater than one year, net of allowance for doubtful accounts	604,924		826,614
Total trade receivables	$	22,670,067	$	16,852,078