Supplemental disclosure of cash flow information (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest paid in cash, net of capitalized interest of $246,851 in 2011	$ 670,042	$ 962,744	$ 1,381,829
Non-cash transactions:
Transfers between inventory and property plant and equipment, net	508,107	(100,000)	0
Note received for plant facility sold	0	0	3,670,963
Issuance of 21,686, 11,158 and 8,565, respectively, of common stock for services rendered	175,313	104,443	119,997
Issuance of 10,033, 7,455 and 5,379, respectively, of redeemable preferred stock for services rendered	77,856	65,902	67,130
Conversion of 2,629, 2,145 and 4,950, respectively, of redeemable preferred stock to common stock	1,577	1,287	2,970
Dividends declared but not paid	$ 1,096,746	$ 1,094,334	$ 1,092,913