Consolidated Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Property and equipment, accumulated depreciation	$ 3,676,488	$ 3,630,731
Preferred stock, par value (in dollars per share)	$ 0.03	$ 0.03
Preferred stock, shares authorized (in shares)	333,306	333,306
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.03	$ 0.03
Common stock, shares authorized (in shares)	3,333,334	3,333,334
Common stock, shares issued (in shares)	1,020,135	1,006,768
Common stock, shares outstanding (in shares)	1,020,135	1,006,768