Derivative liability (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Apr. 23, 2012 April 2012 Note And Warrant Purchase Agreement [Member]	Dec. 31, 2012 Warrants [Member] April 2012 Note And Warrant Purchase Agreement [Member]	Dec. 31, 2012 Warrants [Member] November 2012 Note And Warrant Purchase Agreement [Member]
Class of Warrant or Right [Line Items]
Issue date					Apr. 23, 2012	Nov. 15, 2012
Number of warrants issued	8,643	59,735			5,349	3,294
Exercise price	$ 0.0269	$ 0.0261	$ 0.0274	$ 0.05	$ 0.05	$ 0.05
Risk-free interest rate	1.78%				1.78%	1.58%
Expected term					3 years	3 years
Volatility	205.30%				205.30%	202.20%
Dividend yield	$ 0	$ 0			$ 0	$ 0
Fair value of the derivative liability	$ 225	$ 281			$ 50	$ 8