Variable Interest Entities - Schedule of Carrying Amount of Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025	Dec. 31, 2024
Current assets
Cash and cash equivalents	$ 10,099	$ 22,841
Prepaid expenses	1,201	216
Total current assets	78,012	23,110
Non-current assets
Property and equipment, net	739	390
Mineral interests, which includes $2,275 related to SEM	23,421	23,327	$ 0
Other non-current assets	210	42
Total non-current assets	24,370	25,727
Total assets	102,382	48,837
Current liabilities
Accounts payable	1,574	1,486
Accrued expenses	736	1,211
Other current liabilities	143	36
Total current liabilities	2,453	3,856
Non-current liabilities
Other non-current liabilities	968	370
Total non-current liabilities	12,643	16,518
Total liabilities	15,096	20,374
Variable Interest Entity
Current assets
Cash and cash equivalents	1,202	10,922
Prepaid expenses	200	118
Total current assets	1,402	11,040
Non-current assets
Property and equipment, net	652	362
Mineral interests, which includes $2,275 related to SEM	2,275	2,275
Other non-current assets	160	42
Total non-current assets	24,233	23,731
Total assets	25,635	34,771
Current liabilities
Accounts payable	841	362
Accrued expenses	267	22
Other current liabilities	133	34
Total current liabilities	1,241	418
Non-current liabilities
Other non-current liabilities	64	20
Total non-current liabilities	64	20
Total liabilities	1,305	438
Variable Interest Entity \| SEM
Non-current assets
Mineral interests, which includes $2,275 related to SEM	$ 23,421	$ 23,327

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).