Note 7 - Other Liabilities - Current and Long Term Liabilities (Details) - USD ($) $ in Thousands	Aug. 31, 2024	Nov. 30, 2023
Remediation liabilities	$ 78	$ 212
Lease obligations	169	192
Income taxes payable	321	0
Other Liabilities, Current	568	404
Remediation liabilities	250	250
Lease obligations	819	609
Other Liabilities, Noncurrent	$ 1,069	$ 859

Represents current lease obligations.

No definition available.

Name:	ng_LeaseObligationsCurrent
Namespace Prefix:	ng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents noncurrent lease obligations.

+ References

No definition available.

+ Details

Name:	ng_LeaseObligationsNoncurrent
Namespace Prefix:	ng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents current remediation liabilities.

+ References

No definition available.

+ Details

Name:	ng_RemediationCurrentLiabilities
Namespace Prefix:	ng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents noncurrent remediation liabilities.

+ References

No definition available.

+ Details

Name:	ng_RemediationNoncurrentLiabilities
Namespace Prefix:	ng_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(15)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

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

- Definition

Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

+ Details

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

- Definition

Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

+ References

+ Details

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