Accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities and Other Liabilities [Abstract]
Accrued professional fees	$ 187	$ 328
Accrued compensation and related expenses	161	193
Other	393	509
Accounts payable and accrued expenses	$ 741	$ 1,030