Goodwill and intangible assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Goodwill And Intangible Assets Disclosure [Line Items]
Amortization Of Intangible Assets	$ 150	$ 183	$ 300	$ 300