Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accrued Liabilities
Accrued compensation and other payroll liabilities	$ 293	$ 306
Legal costs	253	91
Accrued interest	39	38
Other research and development expenses	427	522
Other general and administrative expenses	42	53
Total	$ 1,054	$ 1,010