Number Of Shares Of Common Stock

No definition available.

Name:	gnln_NumberOfSharesOfCommonStock
Namespace Prefix:	gnln_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Payment For Lease Termination

+ References

No definition available.

+ Details

Name:	gnln_PaymentForLeaseTermination
Namespace Prefix:	gnln_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Proceeds from issuance of Class A common stock, net of costs - ATM Program

+ References

No definition available.

+ Details

Name:	gnln_ProceedsFromIssuanceOfClassACommonStockNetOfCostsATMProgram
Namespace Prefix:	gnln_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Proceeds from Issuance of Common Stock And Warrants, Gross

+ References

No definition available.

+ Details

Name:	gnln_ProceedsFromIssuanceOfCommonStockAndWarrantsGross
Namespace Prefix:	gnln_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Stock Issued During Period, Shares, Warrants Exercised

+ References

No definition available.

+ Details

Name:	gnln_StockIssuedDuringPeriodSharesWarrantsExercised
Namespace Prefix:	gnln_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

Amount of gain (loss) on termination of lease before expiration of lease term.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 40
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=123386189&loc=SL77918607-209975

+ Details

Name:	us-gaap_GainLossOnTerminationOfLease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

Name:	us-gaap_IncreaseDecreaseInInventories
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

+ Details

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

- Definition

Amount of cash inflow from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as investing activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 19
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3444-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=123583714&loc=SL75117360-209713

+ Details

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

- Definition

Cash outflows under financing arrangements with vendors (seller-financed debt), which had a maturity date at inception of more than one year (or more than one operating cycle, if longer); such debt may have arisen from purchases of property, plant and equipment or other productive assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongtermLoansFromVendors
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

+ Details

Name:	us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=gnln_PreFundedWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=gnln_StandardWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gnln_WarehouseGoodsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gnln_HighTideMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gnln_MergerSubGotham2LLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gnln_XSFinancialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=gnln_October2022OfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands							1 Months Ended		9 Months Ended
	Nov. 03, 2022	Oct. 27, 2022	Oct. 24, 2022	Jul. 18, 2022	Jun. 27, 2022	Aug. 09, 2021	Nov. 14, 2022	Oct. 31, 2022	Sep. 30, 2022	Sep. 30, 2021	Oct. 13, 2022
Subsequent Event [Line Items]
Decrease in inventory									$ 19,044	$ 9,723
Proceeds from issuance of Class A common stock, net of costs									$ 14,064	$ 29,539
Number of securities called by each warrant (in shares)					1	0.6
Proceeds from offering, gross					$ 5,400	$ 31,900
Proceeds from issuance of Class A common stock, net of costs					$ 5,000	$ 29,900
Pre-Funded Warrants
Subsequent Event [Line Items]
Number of common shares called by warrants (in shares)					495,000	296,329
Warrant exercise price (in dollars per share)						$ 0.20
Standard Warrants
Subsequent Event [Line Items]
Number of common shares called by warrants (in shares)					1,080,000	303,797
Warrant exercise price (in dollars per share)						$ 71.00
Warrants outstanding, term						5 years
Subsequent Event
Subsequent Event [Line Items]
Proceeds from sale of equity securities							$ 700
Number of securities called by each warrant (in shares)		2
Payment For Lease Termination	$ 460
Estimated gain on termination of lease	1,700
Subsequent Event \| Warehouse Goods \| High Tide
Subsequent Event [Line Items]
Class A shares sold			38,839
Proceeds from issuance of Class A common stock, net of costs			$ 50
Subsequent Event \| Merger Sub Gotham 2, LLC \| XS Financial
Subsequent Event [Line Items]
Proceeds from sale of equity securities	$ 650
Subsequent Event \| October 2022 Offering
Subsequent Event [Line Items]
Proceeds from offering, gross		$ 7,500
Proceeds from issuance of Class A common stock, net of costs		$ 6,800
Subsequent Event \| October 2022 Offering \| Pre-Funded Warrants
Subsequent Event [Line Items]
Number of common shares called by warrants (in shares)		1,377,780
Number of securities called by each warrant (in shares)		1
Warrant exercise price (in dollars per share)		$ 0.0001
Subsequent Event \| October 2022 Offering \| Standard Warrants
Subsequent Event [Line Items]
Number of common shares called by warrants (in shares)		16,666,670
Number of securities called by each warrant (in shares)		2
Warrant exercise price (in dollars per share)		$ 0.90
Warrants outstanding, term		7 years
Class A Common Stock
Subsequent Event [Line Items]
Class A shares sold					585,000	210,000
Number of shares of common stock per unit (in shares)					1	1
Warrants exercised (in shares)						296,329
Class A Common Stock \| Pre-Funded Warrants
Subsequent Event [Line Items]
Warrant exercise price (in dollars per share)					$ 0.002
Class A Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Number of shares of common stock per unit (in shares)		1
Class A Common Stock \| Subsequent Event \| October 2022 Offering
Subsequent Event [Line Items]
Class A shares sold		6,955,555
Warrants exercised (in shares)								1,377,780
Vendor Loan
Subsequent Event [Line Items]
Repayment of vendor loan				$ 1,000
Debt instrument, face amount				6,000
Decrease in inventory				$ 1,100
Vendor Loan \| Subsequent Event
Subsequent Event [Line Items]
Debt instrument, face amount											$ 1,800