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, 2020	Mar. 31, 2019	Dec. 31, 2019	[1]	May 31, 2017	Nov. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		11,300
Weighted Average Number of Shares Outstanding, Diluted, Total (in shares)		2,668,590	2,659,859
Earnings Per Share, Diluted, Total (in dollars per share)		$ 0.05	$ (0.14)
Letters of Credit Outstanding, Amount	$ 0	$ 0
Accounts Receivable, Allowance for Credit Loss, Current	325	325		$ 335
Amortization of Intangible Assets, Total		51	$ 54
Impairment of Long-Lived Assets to be Disposed of		0	0
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense		39	44
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 341	$ 341
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 284 days
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
Share-based Payment Arrangement, Expense			$ 116
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		0	137,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)			132,500

[1] The balance sheet at December 31, 2019 has been derived from the audited financial statements at that date