Balance Sheet Details - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets [Abstract]
Refundable withholding tax	$ 3,375
Prepaid manufacturing costs	529	$ 930
Prepaid clinical costs	294	820
Prepaid insurance	319	505
Other prepaid expenses and current assets	1,587	1,133
Total prepaid expenses and other current assets	$ 6,104	$ 3,388