Note 10 - Commitments and Contingencies (Details Textual)	1 Months Ended	3 Months Ended	12 Months Ended
	May 31, 2021 bbl	Dec. 31, 2021 USD ($) bbl	Dec. 31, 2021 USD ($) bbl	Jun. 30, 2021 USD ($) a	Dec. 31, 2020 USD ($)
Oncor [Member]
Letters of Credit Outstanding, Amount				$ 1,900,000
TEXAS
Area of Land (Acre) | a				80
The Salt-Water Disposal Agreement Due on July 24, 2022 [Member]
Number of Barrels to be Delivered (Barrel of Oil) | bbl			3,000,000.0
Number of Barrels, Delivered (Barrel of Oil) | bbl			2,500,000
Supply Commitment, Remaining Minimum Amount Committed		$ 236,000	$ 236,000
Crude Oil Delivery Commitments [Member]
Number of Barrels, Delivered (Barrel of Oil) | bbl		17,247
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Year One (Barrel of Oil) | bbl	5,000
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Year Two (Barrel of Oil) | bbl	7,500
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Remaining Term of Contract (Barrel of Oil) | bbl	10,000
Supply Commitment, Remaining Term of Contract (Year)	8 years
Supply Commitment, Amount Committed		$ 24,400,000	24,400,000
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset		852,000	852,000		$ 506,000
Other Liabilities [Member]
Operating Lease, Liability, Total		856,000	856,000		508,000
Other Current Liabilities [Member]
Operating Lease, Liability, Noncurrent		513,000	513,000		430,000
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent		$ 343,000	$ 343,000		$ 78,000