Note 6 - Stockholders' Equity (Details Textual) - Stock Repurchase Program [Member] - USD ($)	12 Months Ended	13 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 05, 2018
Stock Repurchase Program, Authorized Amount				$ 2,400,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased				409,000
Stock Repurchased During Period, Shares	18,102	129,991	148,093

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration