Condensed Consolidated Balance Sheets (Parentheticals) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable, reserve	$ 2,169,958	$ 2,357,191
Vessels and vessel improvements, accumulated depreciation	206,815,553	177,771,755
Other fixed assets, accumulated depreciation	$ 1,346,243	$ 1,137,562
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	12,863,998	11,661,797
Common stock outstanding (in shares)	12,863,998	11,661,797