Note 9 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2020			2019
Expected amount	$	(1,865	)	$	(17,262	)
State income taxes, net of federal benefit		(644	)		(3,831	)
Percentage depletion		(2,154	)		(1,475	)
Valuation allowance		1,275			—
Stock-based compensation		67			326
Return to provision adjustments		(60	)		(78	)
Other		723			(27	)
	$	(2,658	)	$	(22,347	)

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	2020			2019
Long-term deferred tax assets:
Net operating loss	$	24,081		$	18,956
Valuation allowance		(1,275	)		—
Interest limitation carryforward		—			1,801
Capital loss carryforward		525			555
Alternative minimum tax credit		—			524
Stock-based compensation		179			135
Other		529			1,029
Total long-term deferred tax assets:		24,039			23,000
Coal properties		(26,863	)		(27,884	)
Net deferred tax liability	$	(2,824	)	$	(4,884	)