Nature of business, basis of presentation and summary of significant accounting policies (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 409	$ 775	$ 415	$ 945
Accumulated deficit	$ (125,231)	$ (123,199)