Income taxes (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Federal Tax [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 34,572
Operating Loss Carry forwards Expiration Dates	Fiscal 2023
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	18,052
Operating Loss Carry forwards Expiration Dates	Fiscal 2031
Federal Capital [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 553
Operating Loss Carry forwards Expiration Dates	Fiscal 2015