UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Cash flows used in operating activities:
Net loss	$ (11,759)	$ (20,749)
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	2,998	9,615
Depreciation and amortization	534	616
Stock-based compensation	528	679
Asset retirement obligation adjustments and accretion expense	333	2,223
(Gain) loss on sale of equipment, net	(57)	132
Miscellaneous gain	(122)	(1,436)
Changes in operating assets and liabilities:
Receivables, net	41	1
Supplies inventories, net	41	113
Prepaids and deposits	911	(351)
Accounts payable, accrued expenses, and other liabilities	(3,143)	(2,576)
Net cash used in operating activities	(9,695)	(11,733)
Cash flows (used in) provided by investing activities:
Proceeds from sale of assets	57	270
Additions to property, plant, and equipment	(171)	(25)
Net cash (used in) provided by investing activities	(114)	245
Cash flows provided by (used in) financing activities:
Proceeds from issuance of common stock	258	1,160
Principal payments	(33)	(38,023)
Public offering issuance costs (exclusive of accrued amount of $76)	(43)	0
Net cash provided by (used in) financing activities	182	(36,863)
Net decrease in cash, cash equivalents, and restricted cash	(9,627)	(48,351)
Cash, cash equivalents, and restricted cash, beginning of period	77,057	132,550
Cash, cash equivalents, and restricted cash, end of period	67,430	84,199
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	39,688	57,566
Restricted cash	27,742	26,633
Total cash, cash equivalents, and restricted cash	$ 67,430	$ 84,199