Accounts Receivable (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Components of accounts receivable
Accounts receivable	$ 18,429,512	$ 21,637,365
Less: allowance for doubtful accounts	(1,270,574)	(1,321,328)
Accounts receivable, net	$ 17,158,938	$ 20,316,037