Stock-based compensation (Details Textual) (USD $)	3 Months Ended			3 Months Ended			0 Months Ended			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 1998 Stock Option Plan [Member]	Mar. 31, 2012 1998 Stock Option Plan [Member]	May 12, 2008 1998 Stock Option Plan [Member]	Aug. 31, 2008 Director [Member]	Apr. 12, 2013 Director One [Member]	Jan. 17, 2013 Director One [Member]	Mar. 31, 2013 Director Two [Member]	Dec. 31, 2012 Director Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award Exercisable Date							Aug. 15, 2009
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date							Aug. 15, 2013
Exercised, Weighted-Average Exercise Price	$ 0						$ 0.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	100,000	100,000	100,000
Class of Warrant or Right, Outstanding	30,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	0.63
Accrued stock compensation	$ 15,625	$ 15,625
Stock Issued During Period, Shares, New Issues	86,806	78,126						34,722	31,250	17,362	15,626
Stock Issued During Period Per Share Value Of New Issues	$ 0.18	$ 0.20
Stock Issued During Period, Value, New Issues	$ 15,625	$ 15,625
Warrants Issued Expire Period	July 2014
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted							25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number					50,000
Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Granted Vesting Period Description				one year to four years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized						85,000