Note 4 - Fair Values of Financial Instruments - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Reported Value Measurement [Member]
Financial Assets:
Cash and cash equivalents	$ 5,300	$ 5,532
Accounts receivable	20,299	19,256
Other current assets - restricted cash	1,410	1,333
Financial liabilities:
Accounts payable	(11,742)	(10,663)
Debt	(17,450)	(12,947)
Other liabilities - financed insurance payable	(862)	(656)
Estimate of Fair Value Measurement [Member]
Financial Assets:
Cash and cash equivalents	5,300	5,532
Accounts receivable	20,299	19,256
Other current assets - restricted cash	1,410	1,333
Financial liabilities:
Accounts payable	(11,742)	(10,663)
Debt	(17,450)	(12,947)
Other liabilities - financed insurance payable	$ (862)	$ (656)