Note 3 - Intangible Assets - Summary of Intangible Assets (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Gross carrying amount	$ 526,146	$ 526,177
Accumulated amortization	(149,740)	(174,991)
Aggregate amoritization expense	24,749	25,919
Patents [Member]
Gross carrying amount	526,146	476,177
Accumulated amortization	(149,740)	(126,032)
Licensing Agreements [Member]
Gross carrying amount		50,000
Accumulated amortization		$ (48,959)

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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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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