Note 8 - Commitments and Contingencies (Details Textual) - USD ($)	1 Months Ended	39 Months Ended
	Jun. 30, 2015	Mar. 31, 2021	Dec. 31, 2020
Self-insured Amount per Individual Claim	$ 50,000
Self-insured, Maximum Coverage Policy	$ 1,800,000
Self Insurance Reserve		$ 108,000	$ 150,000
Workers' Compensation, Maximum Coverage Policy		1,800,000
Workers' Compensation, Accumulated Payments on Claims		1,800,000
Workers' Compensation, Estimated Accruals		1,600,000
Other Noncurrent Assets [Member]
Worker's Compensation, Prepaid Amount		$ 189,000