Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2025	Jun. 30, 2024
Current
Cash and cash equivalents	$ 25,554	$ 2,012
Prepaid expenses and other	1,183	916
Total current assets	26,737	2,928
Non-current
Deposits	37	35
Investment in equity securities	3	4
Right-of-use assets	118	181
Land and buildings, net	839	837
Mineral properties	16,085	16,085
Total assets	43,819	20,070
LIABILITIES
Accounts payable and accrued liabilities	1,795	1,843
Warrant liabilities, at fair value		2,365
Convertible debt		7,660
Operating lease liability	98	96
Total current liabilities	1,893	11,964
Warrant liabilities, at fair value	6,852	1,651
Earnout liability, at fair value	5,880	3,817
Operating lease liability	33	104
Total liabilities	14,658	17,536
Commitments and contingencies
Redeemable noncontrolling interest	838	1,534
SHAREHOLDERS’ EQUITY
Common stock, no par value, unlimited shares authorized; 58,491,196 and 38,062,647 shares outstanding, respectively	208,551	163,823
Accumulated deficit	(179,317)	(161,912)
Accumulated other comprehensive loss	(911)	(911)
Total shareholders’ equity	28,323	1,000
Total liabilities, redeemable noncontrolling interest, and shareholders’ equity	$ 43,819	$ 20,070

The element represents earnout liability at fair value.

No definition available.

Name:	niobf_EarnoutLiabilityAtFairValue
Namespace Prefix:	niobf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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).