Note 5 - Long-term Debt (Details Textual)			6 Months Ended
	Jun. 25, 2020 USD ($)	Nov. 13, 2019 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Line of Credit, Exit Fee				$ 10,000,000.0
Long-term Debt, Total			$ 2,362,000	2,515,000
Second Lien Credit Facility [Member]
Line of Credit, Exit Fee			10,000,000.0
Line of Credit [Member] | First Lien Credit Facility [Member]
Long-term Line of Credit, Total			$ 88,500,000
Debt Instrument, Spread on Elected Variable Rate			0.50%
Debt Instrument, Debt Default, Basis Spread on Variable Rate			3.00%
Line of Credit Facility, Interest Rate at Period End			8.75%
Debt Instrument, Collateral Eligible, Minimum Percent of PV-9 of Proven Reserves Required			90.00%
Debt Instrument, Collateral Eligible, Minimum Percent of PV-9 of PDP Reserves Required			95.00%
Debt Instrument, Covenant, Working Capital Reserve	$ 3,000,000.0
Debt Instrument, Covenant, Maximum Capital Expenditures	$ 3,000,000.0
Debt Instrument, Covenant, Minimum Asset Coverage Ratio for Capital Expenditures	1.60
Debt Instrument, Covenant, Maximum Line of Credit Outstanding for Capital Expenditures	$ 50,000,000.0
Debt Instrument, Covenant, Maximum Outstanding and Undisputed Accounts Payable	7,500,000
Debt Instrument, Covenant, Maximum Undisputed Accounts Payable Outstanding with 60 to 90 Days	2,000,000.0
Debt Instrument, Covenant, Maximum Undisputed Accounts Payable Outstanding with Over 90 Days	1,000,000.0
Debt Instrument, Covenant, Maximum Legal and Professional Fees Excluded from General and Administrative Expense Limitations	1,000,000.0
Debt Instrument, Covenant, Maximum Additional Subordinated Debt Allowed to Finance Capital Expenditures	25,000,000.0
Line of Credit Facility, Current Borrowing Capacity	102,000,000.0
Line of Credit [Member] | First Lien Credit Facility [Member] | General and Administrative Expenses for Quarter Ending June 30, 2020 [Member]
Debt Instrument, Covenant, Maximum Quarterly General and Administrative Expenses	9,000,000.0
Line of Credit [Member] | First Lien Credit Facility [Member] | General and Administrative Expenses for Quarter Ending September 30, 2020 [Member]
Debt Instrument, Covenant, Maximum Quarterly General and Administrative Expenses	8,250,000
Line of Credit [Member] | First Lien Credit Facility [Member] | General and Administrative Expenses for Quarter Ending December 31, 2020 [Member]
Debt Instrument, Covenant, Maximum Quarterly General and Administrative Expenses	6,900,000
Line of Credit [Member] | First Lien Credit Facility [Member] | General and Administrative Expenses for Year End December 31, 2021 [Member]
Debt Instrument, Covenant, Maximum Yearly General and Administrative Expenses	6,500,000
Line of Credit [Member] | First Lien Credit Facility [Member] | General and Administrative Expenses After Year End December 31, 2021 [Member]
Debt Instrument, Covenant, Maximum Yearly General and Administrative Expenses	$ 5,000,000.0
Line of Credit [Member] | First Lien Credit Facility [Member] | Minimum [Member]
Debt Instrument, Spread on Elected Variable Rate			2.50%
Debt Instrument, Basis Spread on Variable Rate			1.50%
Line of Credit [Member] | First Lien Credit Facility [Member] | Maximum [Member]
Debt Instrument, Spread on Elected Variable Rate			3.50%
Debt Instrument, Basis Spread on Variable Rate			2.50%
Debt Instrument, Covenant, Total Debt to EBITDAX Ratio	2.75
Debt Instrument, Covenant, Asset Coverage Ratio, Current	1.15
Debt Instrument, Covenant, Asset Coverage Ratio, Noncurrent	1.25
Line of Credit [Member] | Second Lien Credit Facility [Member]
Long-term Line of Credit, Total			$ 132,100,000
Debt Instrument, Covenant, Maximum Outstanding and Undisputed Accounts Payable	$ 7,500,000
Debt Instrument, Covenant, Maximum Undisputed Accounts Payable Outstanding with 60 to 90 Days	2,000,000.0
Debt Instrument, Covenant, Maximum Undisputed Accounts Payable Outstanding with Over 90 Days	1,000,000.0
Line of Credit Facility, Maximum Borrowing Capacity		$ 100,000,000.0
Proceeds from Lines of Credit, Total		$ 95,000,000.0
Line of Credit, Exit Fee			$ 10,000,000	10,000,000
Debt Instrument, Collateral Eligible, Minimum Percent of PV-9 Proven Reserves		90.00%
Debt Instrument, Collateral Eligible, Minimum Percent of PV-9 Required PDP Reserves		95.00%
Line of Credit [Member] | Second Lien Credit Facility [Member] | General and Administrative Expenses for Quarter Ending June 30, 2020 [Member]
Debt Instrument, Covenant, Maximum Quarterly General and Administrative Expenses	9,000,000.0
Line of Credit [Member] | Second Lien Credit Facility [Member] | General and Administrative Expenses for Quarter Ending September 30, 2020 [Member]
Debt Instrument, Covenant, Maximum Quarterly General and Administrative Expenses	8,250,000
Line of Credit [Member] | Second Lien Credit Facility [Member] | General and Administrative Expenses for Year End December 31, 2021 [Member]
Debt Instrument, Covenant, Maximum Yearly General and Administrative Expenses	6,500,000
Line of Credit [Member] | Second Lien Credit Facility [Member] | General and Administrative Expenses After Year End December 31, 2021 [Member]
Debt Instrument, Covenant, Maximum Yearly General and Administrative Expenses	$ 5,000,000.0
Line of Credit [Member] | Second Lien Credit Facility [Member] | Maximum [Member]
Debt Instrument, Covenant, Asset Coverage Ratio, Noncurrent, Year Two	1.45
Debt Instrument, Covenant, Asset Coverage Ratio, Noncurrent, after Year Two	1.55
Construction Loans [Member]
Debt Instrument, Interest Rate, Stated Percentage			4.90%
Debt Instrument, Periodic Payment, Total			$ 35,672
Long-term Debt, Total			$ 2,700,000	$ 2,800,000