CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows used in operating activities:
Net loss	$ (60,828)	$ (88,564)
Adjustments to reconcile net loss for the period to net cash used in operating activities:
Non-cash portion of interest expense – Note 10	13,149	16,812
Non-cash loss (gain) on fair value adjustment for warrant liabilities – Note 12	159	(14,426)
Depreciation and amortization	3,356	8,429
Stock-based compensation – Note 16	2,469	2,264
Accretion – Note 13	408	408
Asset retirement obligation adjustments – Note 13	4,701	0
Impairment charges and write-downs – Notes 3, 5, and 7	1,051	17,326
(Gain) loss on sale of equipment	(3,948)	16
Gain on extinguishment of debt – Note 10	5,041	0
Changes in operating assets and liabilities:
Accounts receivable	(2,774)	426
Income tax receivable – Note 17	0	(1,530)
Interest receivable	(459)	0
Production-related inventories	15,808	29,015
Materials and supplies inventories	1,464	(6,186)
Prepaids and deposits	(498)	1,690
Accounts payable	(3,786)	(2,851)
Contract liabilities – Note 8	1,050	0
Other liabilities	(1,136)	133
Net cash used in operating activities	(34,855)	(37,038)
Cash flows provided by (used in) investing activities:
Additions to plant, equipment, and mine development	(951)	(6,990)
Proceeds from sale of equipment – Note 5	2,714	117
Proceeds from assets held for sale, net of commissions expense – Note 7	6,574	0
Net cash provided by (used in) investing activities	8,337	(6,873)
Cash flows provided by (used in) financing activities:
Principal payments on debt	(32,885)	(5,405)
Principal payments on finance leases	(125)	(89)
Proceeds from issuance of common stock and warrants, net of issuance costs – Note 14	188,859	0
Net cash provided by (used in) financing activities	155,849	(5,494)
Net increase (decrease) in cash, cash equivalents, and restricted cash	129,331	(49,405)
Cash, cash equivalents, and restricted cash, beginning of period	46,635	96,040
Cash, cash equivalents, and restricted cash, end of period	175,966	46,635
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	141,984	12,342
Restricted cash	33,982	34,293
Total cash, cash equivalents, and restricted cash	$ 175,966	$ 46,635