Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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-Topic 718
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The maximum awards to each employee under the plan per period.

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Note 11 - Equity Plans (Details Textual) - USD ($)			3 Months Ended		12 Months Ended
Note 11 - Equity Plans (Details Textual) - USD ($)	Jan. 01, 2020	Jan. 01, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			70,588	156,562
Restricted Stock Units (RSUs) [Member] \| Supplemental Employee Retirement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					62,229
Restricted Stock Units (RSUs) [Member] \| Senior Management Stock Incentive Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			5 years
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Participant's Base Salary			10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Amount Per Employee			$ 17,500
Restricted Stock Units (RSUs) [Member] \| Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Value			$ 80,000	$ 80,000
Restricted Stock Units (RSUs) [Member] \| Non-Employee Director [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			1 year
Restricted Stock Units (RSUs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		5 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		51,506
Restricted Stock Units (RSUs) [Member] \| Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	15,694	14,891
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)			1,000,000