Schedule: II - Valuation and Qualifying Accounts (Details) (Allowance for doubtful accounts and sales returns, USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts and sales returns
Changes to valuation and qualifying accounts
Balance at Beginning of Year	$ 150,921	$ 183,291	$ 162,315
Charged to Costs and Expenses	257,310	16,653	102,860
Deductions	104,392	49,023	81,884
Balance at End of Year	$ 303,839	$ 150,921	$ 183,291