Supplemental disclosure of cash flow information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Disclosure Of Cash Flow Information [Line Items]
Interest paid in cash	$ 74,898	$ 147,546	$ 196,768
Non-cash transactions:
Transfers from inventory to property plant and equipment and construction in progress	276,807	123,036	168,622
Transfers from construction in progress to property, plant and equipment	3,542,119	2,694,733	2,693,622
Issuance of 25,156, 10,514, and 18,294, respectively, shares of common stock for services rendered	278,388	119.018	263,098
Issuance of 8,421, 8,615, and 5,957, respectively, shares of redeemable preferred stock for services rendered	111,410	110,703	65,289
Conversion (on a one-to-one basis) of 11,558, 7,195, and 4,756, respectively, shares of redeemable preferred stock to common stock	6,935	4,317	2,854
Dividends declared but not paid	$ 1,118,017	$ 1,111,501	$ 1,106,456