Selected Balance Sheet Information - Schedule of accrued expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Selected Balance Sheet Information
Accrued manufacturing costs	$ 1,283	$ 83
Accrued clinical consulting services	709	674
Accrued vendor payments	323	150
Other accrued expenses	6	12
Total	$ 2,321	$ 919