UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash flows used in operating activities:
Net loss	$ (23,496)	$ (33,930)
Adjustments to reconcile net loss for the period to net cash used in operating activities:
Non-cash interest expense, including accelerated amortization of original issue discount and issuance costs	6,076	12,396
Depreciation and amortization	1,032	1,183
Stock-based compensation	1,164	1,479
Asset retirement obligation adjustments and accretion expense	666	4,491
Gain on sale of assets, net	(68)	(5,060)
Other non-cash items	(484)	495
Changes in operating assets and liabilities:
Accounts payable, accrued expenses, and other liabilities	(3,208)	(1,109)
Receivables	97	307
Supplies inventories, net	30	52
Prepaids and deposits	(527)	(635)
Net cash used in operating activities	(18,718)	(20,331)
Cash flows (used in) provided by investing activities:
Proceeds from sale of assets	68	1,717
Additions to property, plant, and equipment	(397)	(449)
Net cash (used in) provided by investing activities	(329)	1,268
Cash flows provided by (used in) financing activities:
Proceeds from issuance of common stock, net of issuance costs (exclusive of $294 accrued issuance costs)	40,784	10,053
Principal payments	(25)	(38,057)
Net cash provided by (used in) financing activities	40,759	(28,004)
Net increase (decrease) in cash, cash equivalents, and restricted cash	21,712	(47,067)
Cash, cash equivalents, and restricted cash, beginning of period	77,057	132,550
Cash, cash equivalents, and restricted cash, end of period	98,769	85,483
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	68,768	58,548
Restricted cash	30,001	26,935
Total cash, cash equivalents, and restricted cash	$ 98,769	$ 85,483