Note 2 - Basis of Presentation and Summary of Significant Accounting Policies (Details Textual)	1 Months Ended		2 Months Ended	3 Months Ended	6 Months Ended	8 Months Ended	9 Months Ended		12 Months Ended	20 Months Ended
	Dec. 31, 2020 USD ($) shares	Sep. 30, 2020 USD ($)	Aug. 21, 2020 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Aug. 21, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Aug. 21, 2020 USD ($)
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 7,722,000			$ 23,891,000			$ 23,891,000		$ 7,722,000
Income Taxes Receivable	3,200,000			3,200,000			3,200,000		3,200,000
Oil and Gas Joint Interest Billing Receivables	345,000			1,100,000			1,100,000		345,000
Accounts Receivable, Allowance for Credit Loss, Current	$ 0			0			0		0
Class of Warrant or Right, Exercised During Period (in shares) | shares	312,711
Proceeds from Warrant Exercises	$ 3,600,000	$ 0				$ 0	5,466,000
Subscription Receivable, Current	3,596,000			0			0		3,596,000
Inventory, Raw Materials and Supplies, Gross, Total	121,000			3,900,000			3,900,000		121,000
Inventory, LIFO Reserve	0			0			0		0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance	237,000			385,000			385,000		237,000
Debt Issuance Costs, Gross				2,200,000			2,200,000
Payments of Debt Issuance Costs		(0)				(0)	1,757,000
Amortization of Debt Issuance Costs		0				0	259,000
Accounts Payable and Accrued Liabilities, Current, Total	22,400,000			77,000,000.0			77,000,000.0		$ 22,400,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total				0			0
Income Tax Expense (Benefit), Total		$ (2,309,000)	$ 0	2,145,000		$ 0	$ 4,680,000			$ 0
Number of Operating Segments							1
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Open Tax Year							2017 2018 2019 2020		2017 2018 2019
Minimum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)							1 month
Maximum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)							2 months
Revolving Credit Facility [Member]
Debt Issuance Costs, Gross					$ 2,200,000
Payments of Debt Issuance Costs					$ 1,800,000
Amortization of Debt Issuance Costs							$ 259,000	$ 0
WTG Gas Processing, L.P. [Member] | Aid-in-construction Receivables [Member]
Accounts Receivable, after Allowance for Credit Loss, Total				3,900,000			$ 3,900,000
Technology Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)							3 years
Transportation Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)							5 years
Field Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)							7 years
Crude Oil, Natural Gas and Natural Gas Liquids [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 4,200,000			$ 19,600,000			$ 19,600,000		$ 4,200,000