Summary of significant accounting policies (Details Textual) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Amortization Description	Amortization expense is expected to be approximately $102 for the remainder of 2012 and be approximately $204 for each of the next five fiscal years.
Amortization	$ 17,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	102,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	204,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	204,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	204,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	204,000
Mgt [Member]
Proceeds From Sale Of Convertable Notes	3,500,000
Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share, Amount	6	31
Stock Options Weighted Average Price Per Share	$ 46,326,000	$ 78,000,000