UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Cash flows used in operating activities:
Net loss	$ (14,228,000)	$ (15,712,000)	$ (48,158,000)	$ (43,510,000)
Adjustments to reconcile net loss for the period to net cash used in operating activities:
Non-cash interest expense – Note 11			15,249,000	9,096,000
Asset retirement obligation adjustments – Note 13			6,261,000	0
Stock-based compensation – Note 16			2,083,000	2,200,000
Depreciation and amortization – Notes 2 and 6			1,706,000	2,155,000
Accretion – Note 13	372,000	186,000	899,000	558,000
Unrealized loss on securities – Note 5	287,000	0	777,000	0
Write-down of supplies inventories – Note 4	366,000	0	378,000	0
Gain on settlement of accrued liability	0	0	0	(1,151,000)
Gain on fair value adjustment for warrant liabilities	(4,000)	(1,000)	(11,000)	(182,000)
Gain on forfeiture of non-refundable deposit – Notes 8 and 12	0	0	(1,550,000)	0
Gain on sale of equipment, net – Note 18	(2,636,000)	(456,000)	(2,505,000)	(541,000)
Gain on sale of patents and intellectual property – Note 5	0	0	(3,641,000)	0
Changes in operating assets and liabilities:
Accounts payable and accrued expenses			1,153,000	(1,416,000)
Interest receivable			341,000	(59,000)
Supplies inventories, net – Note 4			11,000	(4,000)
Contract liabilities – Note 12			0	100,000
Prepaids – Note 3			(3,000)	(1,392,000)
Other receivables			(7,000)	2,771,000
Other liabilities – Note 9			(785,000)	(556,000)
Net cash used in operating activities			(27,802,000)	(31,931,000)
Cash flows provided by (used in) investing activities:
Proceeds from sale of equipment			5,671,000	559,000
Proceeds from sale of patents and intellectual property – Note 5			1,447,000	0
Additions to property, plant, and equipment			(979,000)	(851,000)
Net cash provided by (used in) by investing activities			6,139,000	(292,000)
Cash flows used in financing activities:
Proceeds from issuance of common stock, net of issuance costs – Note 15			10,278,000	0
Principal payments on notes payable			(96,000)	(95,000)
Principal payments on debt – Note 11			(37,995,000)	(1,650,000)
Net cash used in financing activities			(27,813,000)	(1,745,000)
Net decrease in cash, cash equivalents, and restricted cash			(49,476,000)	(33,968,000)
Cash, cash equivalents, and restricted cash, beginning of period			132,550,000	175,966,000
Cash, cash equivalents, and restricted cash, end of period	83,074,000	141,998,000	83,074,000	141,998,000
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	55,834,000	106,911,000	55,834,000	106,911,000
Restricted cash	27,240,000	35,087,000	27,240,000	35,087,000
Total cash, cash equivalents, and restricted cash	$ 83,074,000	$ 141,998,000	$ 83,074,000	$ 141,998,000