Cash and Restricted Cash - Cash and Restricted Cash (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Notes to Financial Statements
Cash	$ 262,608	$ 774,226
Restricted cash	0	0
Cash and restricted cash	$ 262,608	$ 774,226	$ 13,602,118	$ 13,496,379