Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating loss carryforwards
Valuation allowance for deferred tax assets	$ 363,000	$ 2,462,000
State and Local Jurisdiction [Member]
Operating loss carryforwards
Valuation allowance for deferred tax assets	363,000
Decrease in valuation allowances	$ 2,099,000	$ 4,543,000	$ 1,286,000