Supplemental disclosure of cash flow information (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest Costs Capitalized		246,851
Common Stock [Member]
Stock Issued During Period, Shares, Issued for Services	21,686	11,158	8,565
Redeemable Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	10,033	7,455	5,379
Conversion of preferred stock (in shares)	2,629	2,145	4,950