Marketable Securities - Summary of Gain (Loss) on Securities Transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 20,107	$ 1,749,034	$ 2,287,454
Gross realized losses	0	(1,506)	(2,153)
Total Realized Gain on Sales of Securities, net	$ 20,107	$ 1,747,528	$ 2,285,301