Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid contracted research and development costs	$ 531	$ 1,822
R&D tax credit receivable	780	792
Prepaid insurance	201	231
VAT receivable	171	162
Deposits and other	162	71
Total prepaid expenses and other current assets	$ 1,845	$ 3,078