Note 1 - Organization and Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2022

Notes Tables

Schedule of Cash, Cash Equivalents and Restricted Cash [Table Text Block]

	As of September 30,
	2022		2021
	(in thousands)
Cash and cash equivalents	$	69,289	$	52,839
Restricted cash - current		203		81
Restricted cash - non-current		1,755		1,752
Abandonment funding		18,838		22,281
Total cash, cash equivalents and restricted cash	$	90,085	$	76,953

Accounts Receivable, Allowance for Credit Loss [Table Text Block]

	Three Months Ended September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
	(in thousands)
Allowance for bad debt
Balance at beginning of period	$	(6,389	)	$	(5,575	)	$	(5,741	)	$	(2,273	)
Bad debt charge, net of receipts		(1,020	)		(318	)		(2,083	)		(814	)
Adjustment associated with Sasol Acquisition		—			—			—			(2,879	)
Foreign currency gain (loss)		355			117			770			190
Balance at end of period	$	(7,054	)	$	(5,776	)	$	(7,054	)	$	(5,776	)

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

		As of September 30, 2022
	Balance Sheet Line	Level 1		Level 2		Level 3		Total
		(in thousands)
Assets
Derivative asset	Prepayments and other	$	—	$	348	$	—	$	348
		$	—	$	348	$	—	$	348
Liabilities
SARs liability	Accrued liabilities and other	$	—	$	544	$	—	$	544
		$	—	$	544	$	—	$	544

		As of December 31, 2021
	Balance Sheet Line	Level 1		Level 2		Level 3		Total
		(in thousands)
Liabilities
SARs liability	Accrued liabilities and other	$	—	$	609	$	—	$	609
Derivative liability	Accrued liabilities and other		—		4,806		—		4,806
		$	—	$	5,415	$	—	$	5,415