Selected Balance Sheet Information (Details 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses [Line Items]
Accrued clinical consulting services	$ 674	$ 658
Accrued vendor payments	150	193
Accrued manufacturing costs	83	661
Other accrued expenses	12	14
Total	$ 919	$ 1,526