Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities And Other Liabilities [Abstract]
Accrued compensation	$ 1,270	$ 571
Accrued contracted research and development costs	1,749	863
Accrued professional and consulting fees	480	863
Accrued and other current liabilities	227	50
Total accrued and other current liabilities	$ 3,726	$ 2,347