Note 3 - Property and Equipment (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization, Total	$ 74,237,000
Depreciation, Total	4,783,000	$ 4,972,000
Net Income (Loss) Attributable to Parent, Total	$ 1,328,000	$ 194,000
Earnings Per Share, Diluted, Total (in dollars per share)	$ 0.21	$ 0.03
Gain (Loss) on Sale of Assets and Asset Impairment Charges	$ (0)	$ (105,000)
Asset Impairment Charges, Total	0	105,000
PBRT Equipment [Member]
Asset Impairment Charges, Total	0	0
Salvage Value [Member]
Net Income (Loss) Attributable to Parent, Total	$ 17,000
Earnings Per Share, Diluted, Total (in dollars per share)	$ 0.00
Non-US [Member]
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization, Total	$ 2,201,000	$ 2,697,000