8. Derivative liability (Details) (USD $)	6 Months Ended	12 Months Ended
8. Derivative liability (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Derivative [Line Items]
Risk-free interest rate	16.00%	12.00%
Expected volatility	117.00%	92.00%
Expected life (in years)	0.25 - 0.50	0.75 - 1.00
Expected dividend yield	0
Total Fair Value	$ 1,725,138	$ 1,643,139
2009 Summer Warrants [Member]
Derivative [Line Items]
Total Fair Value	367,896	332,998
2009 Wellfleet Warrants [Member]
Derivative [Line Items]
Total Fair Value	0	17,807
2009 Fall Warrants [Member]
Derivative [Line Items]
Total Fair Value	$ 1,357,242	$ 1,292,334