Note 2 - Basis of Presentation and Summary of Significant Accounting Policies - Other Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Other property and equipment, net	$ 1,637	$ 1,600
Land [Member]
Other property and equipment, net	1,122	1,122
Transportation Equipment [Member]
Other property and equipment, net	257	202
Leasehold Improvements [Member]
Other property and equipment, net	167	143
Technology Equipment [Member]
Other property and equipment, net	83	125
Field Equipment [Member]
Other property and equipment, net	$ 8	$ 8