CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Cash and cash equivalents	$ 58,548	$ 106,210
Prepaids and deposits – Note 3	4,589	3,326
Supplies inventories, net – Note 4	1,770	1,834
Income tax receivable	1,530	1,530
Securities available-for-sale – Notes 7 and 20	426	0
Interest receivable	360	667
Current assets	67,223	113,567
Property, plant, and equipment, net – Note 5	51,957	53,091
Restricted cash – Note 6	26,935	26,340
Assets held-for-sale – Note 8	7,148	7,148
Securities available-for-sale – Notes 7 and 20	1,277	0
Prepaids – Note 3	919	1,547
Total assets	155,459	201,693
Liabilities:
Asset retirement obligation – Note 12	5,290	3,172
Accounts payable and accrued expenses	2,049	1,631
Other liabilities – Note 11	1,459	3,063
Contract liabilities – Note 10	300	1,550
Debt, net – Notes 9 and 21	105	2,330
Current liabilities	9,203	11,746
Debt, net – Notes 9 and 21	119,181	142,617
Deferred gain on sale of royalty	29,839	29,839
Asset retirement obligation – Note 12	6,953	4,801
Warrant liabilities – Notes 13 and 20	14	26
Other liabilities – Note 11	0	8
Total liabilities	165,190	189,037
Commitments and contingencies – Note 22
Stockholders’ equity – Note 14
Common stock, $0.0001 par value; 1,400,000,000 shares authorized; 24,022,151 issued and outstanding at June 30, 2024, and 20,736,612 issued and outstanding at December 31, 2023, respectively	21	21
Additional paid-in capital	749,346	737,810
Accumulated deficit	(759,098)	(725,175)
Total stockholders’ (deficit) equity	(9,731)	12,656
Total liabilities and stockholders’ equity	$ 155,459	$ 201,693