Note 7 - Income Taxes - Income Before Income Taxes (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income from continuing operations, before income taxes	$ 3,703,697	$ 7,163,124	$ 10,202,829
Internal Revenue Service (IRS) [Member]
Income before income taxes	3,347,690	6,372,585	9,070,894
Her Majesty's Revenue and Customs (HMRC) [Member]
Income before income taxes	(385,573)	(171,608)	(81,987)
Canada Revenue Agency [Member]
Income before income taxes	680,388	1,055,783	1,034,027
Australian Taxation Office [Member]
Income before income taxes	(2,454)	(88,096)	82,622
Tax Authority, Spain [Member]
Income before income taxes	$ 63,646	$ (5,540)	$ 97,273

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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