CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)
Cash flows used in operating activities:
Net loss	$ (8,982)	$ (8,427)	$ (31,042)	$ (18,115)
Adjustments to reconcile net loss for the period to net cash used in operating activities:
Non-cash portion of interest expense			6,937	9,215
Non-cash loss (gain) on fair value adjustment for warrant liabilities	(3,706)	(651)	1,615	(10,144)
Depreciation and amortization			1,552	3,102
Stock-based compensation			1,023	1,586
Accretion	102	102	204	204
Gain on sale of equipment	23	0	(602)	0
Changes in operating assets and liabilities:
Accounts receivable			0	(1,037)
Production-related inventories			3,935	(6,285)
Materials and supplies inventories			315	(762)
Prepaids and deposits			(2,468)	(3,045)
Accounts payable			(1,634)	3,010
Other liabilities			(1,918)	954
Net cash used in operating activities			(22,083)	(21,317)
Cash flows provided by (used in) investing activities:
Additions to plant, equipment, and mine development			(490)	(9,065)
Proceeds from sale of equipment			1,383	0
Proceeds from assets held for sale			1,890	0
Net cash provided by (used in) investing activities			2,783	(9,065)
Cash flows provided by financing activities:
Principal payments on debt			(24,956)	(583)
Principal payments on notes payable			(62)	0
Proceeds from issuance of common stock, net of issuance costs			188,974	0
Net cash provided by (used in) financing activities			163,956	(583)
Net increase (decrease) in cash and restricted cash			144,656	(30,965)
Cash and restricted cash, beginning of period			46,635	96,040
Cash and restricted cash, end of period	191,291	65,075	191,291	65,075
Reconciliation of cash and restricted cash:
Cash	157,781	30,220	157,781	30,220
Restricted cash	33,510	34,855	33,510	34,855
Total cash and restricted cash	$ 191,291	$ 65,075	$ 191,291	$ 65,075