Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Prepaid Expense And Other Assets Current [Abstract]
Tax incentive refund	$ 1,916	$ 1,325
Prepaid research and development costs	4,915	981
Prepaid insurance	897	316
Interest income receivable	224	220
Prepaid rent	86	81
Other current assets	620	795
Total	$ 8,658	$ 3,718