Supplemental Balance Sheet Information - Components of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued payroll and compensation	$ 3,193	$ 2,940
Accrued final fee	2,445	1,375
Accrued research and development expenses	267	359
Accrued professional services	511	576
Accrued interest	908
Operating lease liabilities	1,983
Other accrued expenses	1,900	823
Total accrued expenses and other current liabilities	$ 11,207	$ 6,073