Note 3 - Intangible Assets - Summary of Intangible Assets (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Accumulated amortization	$ (207,399)	$ (181,609)
Aggregate amortization expense	25,790	31,869
Patents [Member]
Gross carrying amount	450,982	452,978
Accumulated amortization	$ (207,399)	$ (181,609)

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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