Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities And Other Liabilities [Abstract]
Accrued compensation	$ 3,273	$ 2,643
Accrued contracted research and development costs	10,485	5,993
Accrued professional and consulting fees	627	807
Accrued and other current liabilities	469	133
Total accrued and other current liabilities	$ 14,854	$ 9,576