Fair value assumptions (Details)	12 Months Ended
Fair value assumptions (Details)	Dec. 31, 2013	Dec. 31, 2012
Fair value assumptions
Minimum percentage of Expected volatility	131.97%	114.66%
Maximum percentage of Expected volatility	194.14%	125.11%
Expected dividends percentage	0.00%	0.00%
Expected term in years	3	3
Minimum Risk free rate percentage	0.25%	0.25%
Maximum Risk free rate percentage	0.33%	0.33%