Consolidated Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Accounts receivable, allowance for doubtful accounts	$ 409,076	$ 498,044
Inventories, allowance for excess and obsolete inventory	268,470	723,949
Property and equipment, accumulated depreciation	7,554,803	8,908,145
Intangible assets, accumulated depreciations	$ 357,231	$ 269,441
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	2,500,000	2,500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shared outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	21,285,706	21,655,461
Common stock, shares outstanding (in shares)	21,285,706	21,655,461