Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Current expense (benefit):
U.S. federal	$ 0	$ 0
U.S. state and local	0	0
Total current income tax (benefit) provision	0	0
Deferred expense (benefit):
U.S. federal	0	0
U.S. state and local	0	0
Total deferred income tax (benefit) provision	0	0
Total income tax (benefit) provision	$ 0	$ 0