Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	[1]	May 31, 2017	Nov. 30, 2010
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)			2,668,590
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount (in dollars per share)			$ 0.05
Accounts Receivable, Allowance for Credit Loss, Current		$ 722		$ 343
Amortization of Intangible Assets, Total		46	$ 51
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense		21	$ 39
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 308
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 54 days
Stock Appreciation Rights (SARs) [Member]
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)	50,000
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