Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483466/210-20-50-3

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=galt_ContingentInterestAprilNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=galt_ContingentInterestSeptemberNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=galt_ContingentInterestDecemberNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value of Financial Instruments, Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	$ 1,004,000	$ 573,000
April Note [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	431,000	249,000	$ 495,000
September Note [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	169,000	109,000	250,000
December Note [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	404,000	214,000	$ 384,000
Recurring [Member] \| Level 1 [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Assets	0	0
Liabilities	0	0
Recurring [Member] \| Level 2 [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Assets	0	0
Liabilities	0	0
Recurring [Member] \| April Note [Member] \| Level 3 [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	431,000	249,000
Recurring [Member] \| September Note [Member] \| Level 3 [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	169,000	109,000
Recurring [Member] \| December Note [Member] \| Level 3 [Member]
Assets and Liabilities Measured at Fair Value [Abstract]
Derivative Liability - Contingent Interest	$ 404,000	$ 214,000