RELATED PARTY TRANSACTIONS AND BALANCES (Details) - CEO [Member] $ in Thousands, $ in Thousands	6 Months Ended
Dec. 31, 2019 USD ($)	Dec. 31, 2019 CAD ($)
Non Revolving Line of Credit [Member]
Related Party Transactions and Balances (Textual)
Credit facility interest rate (in dollars per share)	10.00%	10.00%
Credit Agreement [Member]
Related Party Transactions and Balances (Textual)
Principal amount outstanding	$ 1,560
Non-revolving credit facility		$ 2,000
Establishment fee	2.50%
Description of collateral	The Credit Agreement bears an interest rate of 10% and drawdowns from the Credit Agreement are subject to a 2.5% establishment fee. Amounts outstanding under the Credit Agreement are secured by all of the Company's assets pursuant to the General Security Agreement.
Credit Agreement [Member] \| Original Smith Loan [Member]
Related Party Transactions and Balances (Textual)
Description of fees associated with providing collateral for the credit facility	The Company has a loan with Mark Smith, President, Chief Executive Officer ("CEO") and Executive Chairman of NioCorp (the "Original Smith Loan"), that bears an interest rate of 10%, is secured by the Company's assets pursuant to a concurrently executed general security agreement (the "General Security Agreement") and is subject to both a 2.5% establishment fee and 2.5% prepayment fee.
Principal amount outstanding		1,000
Advance paid	$ 1,080
Accounts payable and accrued liabilities		$ 293

Represents additional advance paid.

No definition available.

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It represents as a line of credit facility establishment fee.

+ References

No definition available.

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Sum of the carrying values as of the balance sheet date of obligations incurred through that date, including liabilities incurred and payable to vendors for goods and services received, taxes, interest, rent and utilities, compensation costs, payroll taxes and fringe benefits (other than pension and postretirement obligations), contractual rights and obligations, and statutory obligations.

+ References

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- Definition

Discussion of whether the borrowings under the credit facility are secured or unsecured and, if secured, a description of collateral (for example, accounts receivable less than 120 days old, finished goods inventory).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Description of fees associated with providing collateral for the credit facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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The effective interest rate at the end of the reporting period.

+ References

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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