Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2021	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	[1]	May 31, 2017	Nov. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)					3,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)			109,065			9,002
Accounts Receivable, Allowance for Credit Loss, Current			$ 459		$ 459		$ 343
Amortization of Intangible Assets, Total			46		92
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense			25	$ 36	46	$ 75
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			283		$ 283
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)					2 years 11 months 26 days
Stock Appreciation Rights (SARs) [Member]
Share-based Payment Arrangement, Expense			$ 100	$ 0	$ 114
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					0	0
Stock Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)									400,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)	75,000	50,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)					3,000
Equity Appreciation Rights Plan 2010 [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)										1,000,000

[1] The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date