Note 2 - Basis of Presentation and Summary of Significant Accounting Policies (Details Textual)		1 Months Ended	2 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended		12 Months Ended	20 Months Ended
		Sep. 30, 2020 USD ($)	Aug. 21, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Aug. 21, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Aug. 21, 2020 USD ($)	Aug. 22, 2020 USD ($)
Accounts Receivable, after Allowance for Credit Loss, Current, Total		$ 5,949,000					$ 5,949,000		$ 3,363,000		$ 3,027,000
Income Taxes Receivable		2,300,000					2,300,000		0
Oil and Gas Joint Interest Billing Receivables		77,000					77,000		440,000
Accounts Receivable, Allowance for Credit Loss, Current		0					0		0
Other Payments to Acquire Businesses						$ 15,000,000
Inventory, Raw Materials and Supplies, Gross, Total		405,000					405,000		184,000
Inventory, LIFO Reserve		0					0		0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance		189,000					189,000		46,000
Accounts Payable and Accrued Liabilities, Current, Total		15,100,000					15,100,000		31,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total		0					$ 0
Income Tax Expense (Benefit), Total		(2,309,000)								$ 0
Number of Operating Segments							1
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Open Tax Year							2017 2018 2019
Minimum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)							30 days
Maximum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)							60 days
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
HPK, LP [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	[1]		3,001,000			3,001,000				3,001,000
Grenadier [Member] | HPK, LP [Member]
Payments of Deposits for Acquisition									61,500,000
Other Payments to Acquire Businesses				$ 15,000,000
Acquisition-related Deposits and Extension Payments Charged to Expense				76,500,000
Texas Railroad Commission [Member] | HPK, LP [Member]
Payments Made in Lieu of Plugging Bond				$ 50,000
Pure Acquisition [Member]
Financing Receivable, before Allowance for Credit Loss, Current			$ 11,700,000			$ 11,700,000			4,200,000	$ 11,700,000
Financing Receivable, Allowance for Credit Loss, Current									0
Crude Oil, Natural Gas and Natural Gas Liquids [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total		$ 3,600,000					$ 3,600,000		$ 2,900,000

[1] Represents HPK LP's condensed consolidated balance sheet estimated as of August 21, 2020.