Selected Balance Sheet Information (Details 2) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accrued Expenses [Line Items]
Accrued clinical consulting services	$ 1,129	$ 2,211
Accrued manufacturing costs	368	14
Accrued vendor payments	249	400
Other accrued expenses	4	2
Total	$ 1,750	$ 2,627