Options and warrants - Stock option and warrant activity (Details) (Stock Options and Warrants, USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at beginning	5,405,413	3,215,413
Shares, Options and warrants granted	0	2,450,000
Shares, Options and warrants cancelled or expired	0	(260,000)
Shares, Outstanding at ending	5,405,413	5,405,413
Shares, Exercisable at ending	5,405,413	5,405,413
Share Based Compensation Arrangement By Share Based Payment Award Stock Option And Warrant Weighted Average Exercise Price [Roll Forward]
Range of Exercise Prices, Options and warrants cancelled or expired		$ 2.00
Weighted Average Grant Date Fair Value, Options and warrants granted		$ 0.17
Minimum
Share Based Compensation Arrangement By Share Based Payment Award Stock Option And Warrant Weighted Average Exercise Price [Roll Forward]
Range of Exercise Prices, Outstanding at beginning	0.10	$ 0.10
Range of Exercise Prices, Options and warrants granted		$ 0.15
Range of Exercise Prices, Options and warrants cancelled or expired
Range of Exercise Prices, Outstanding at ending	0.10	$ 0.10
Range of Exercise Prices, Exercisable at ending	0.10	$ 0.10
Maximum
Share Based Compensation Arrangement By Share Based Payment Award Stock Option And Warrant Weighted Average Exercise Price [Roll Forward]
Range of Exercise Prices, Outstanding at beginning	2.00	$ 2.00
Range of Exercise Prices, Options and warrants granted		$ 0.30
Range of Exercise Prices, Options and warrants cancelled or expired
Range of Exercise Prices, Outstanding at ending	2.00	$ 2.00
Range of Exercise Prices, Exercisable at ending	2.00	$ 2.00