Intangible asset - intellectual property (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Apr. 10, 2013
Finite-lived Intangible Assets, Fair Value Disclosure			$ 1,913
Finite Lived Intangible Asset Acquired Cash Paid			200
Stock Issued During Period Shares Purchase Of Warrants			350,000
Warrant Term			4 years
Class of Warrant or Right, Exercise Price of Warrants or Rights	3.85		4.00	3.00
Finite-Lived Intangible Assets, Remaining Amortization Period			nine year
Amortization of intangible assets	52	0
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	204
Finite-Lived Intangible Assets, Amortization Expense, Year Two	204
Finite-Lived Intangible Assets, Amortization Expense, Year Three	204
Finite-Lived Intangible Assets, Amortization Expense, Year Four	204
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 204