Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Prepaid expenses	$ 2,416	$ 615
Prepaid insurance	3,353	57
Tax receivable	3,400	722
Interest receivable	67	213
Other current assets	55	179
Total prepaid expenses and other current assets	$ 9,291	$ 1,786