Note 11 - Sale of Membership Interests in Nevada Subsidiaries (Details Textual) - USD ($)	Dec. 06, 2019	Nov. 27, 2019
Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 470,000
Teco Note [Member] \| Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 470,000
Debt Instrument, Interest Rate, Stated Percentage	8.00%
AJE Management, LLC [Member]
Management Fee	$ 75,000
Teco [Member]
Sale of Stock, Percentage of Ownership		75.00%
Sale of Stock, Consideration Received on Transaction		$ 3,000,000
Sale of Stock, Additional Earn-out Payments		$ 3,000,000
GB Sciences Nopah, LLC [Member]
Sale of Stock, Percentage of Ownership		100.00%
Sale of Stock, Consideration Received on Transaction		$ 300,000

Represents the amount of management fee.

No definition available.

Name:	gblx_ManagementFee
Namespace Prefix:	gblx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of additional earn-out payments by subsidiary or equity investee in exchange for shares of stock issued or sold.

+ References

No definition available.

+ Details

Name:	gblx_SaleOfStockAdditionalEarnoutPayments
Namespace Prefix:	gblx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of subsidiary's or equity investee's stock sold in the stock transaction.

+ References

No definition available.

+ Details

Name:	gblx_SaleOfStockPercentageOfOwnership
Namespace Prefix:	gblx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Cash received on stock transaction after deduction of issuance costs.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gblx_TecoNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=gblx_AjeManagementLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=gblx_TecoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=gblx_GbSciencesNopahLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: