Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

No definition available.

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodFive
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodFour
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodOne
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodSeven
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodSix
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodThree
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of underlying the outstanding whole number of DSUs credited individuals during period.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementPercentageOfDeferredShareUnitsShallBeIssuedPeriodTwo
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The deferred compensation arrangement with individual cash award granted paid in cash percentage.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementWithIndividualCashAwardGrantedPaidInCashPercent
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The deferred compensation arrangement with individual cash award granted paid in deferred stock units percentage.

+ References

No definition available.

+ Details

Name:	galt_DeferredCompensationArrangementWithIndividualCashAwardGrantedPaidInDeferredStockUnitsPercent
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of directors of the company.

+ References

No definition available.

+ Details

Name:	galt_NumberOfDirectors
Namespace Prefix:	galt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Refers to the terms of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter.

+ References

No definition available.

+ Details

Name:	galt_ShareBasedCompensationArrangementByShareBasedPaymentAwardTermOfAward
Namespace Prefix:	galt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

'The vesting percentage of Restricted Stock Units ("RSUs") granted.

+ References

No definition available.

+ Details

Name:	galt_VestingPercentageOfRestrictedStockUnits
Namespace Prefix:	galt_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479983/718-10-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479830/718-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

Amount of common stock allocated to investors to buy shares of a new issue of common stock before they are offered to the public. When stock is sold on a subscription basis, the issuer does not initially receive the total proceeds. In general, the issuer does not issue the shares to the investor until it receives the entire proceeds.

+ 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(29))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow to satisfy grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(02)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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

- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares issued under share-based payment arrangement.

+ References

+ Details

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

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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

- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of non-vested options outstanding.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-4

+ Details

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

- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of options vested.

+ References

+ Details

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

- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

+ Details

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

- Definition

Aggregate value of stock related to Restricted Stock Awards issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-SubTopic 10
-Topic 505
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

Reference 2: 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(28))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: 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(29))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

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

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=srt_ChiefExecutiveOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=us-gaap_DeferredBonusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=galt_EquityIncentivePlan2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=galt_IncentiveCompensationPlanTwoThousandNineMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Compensation (Details)	1 Months Ended		10 Months Ended			12 Months Ended
Stock-Based Compensation (Details)	Jan. 31, 2025 USD ($) shares	Jan. 31, 2024 USD ($) shares	Dec. 31, 2025 USD ($) Director $ / shares shares	Dec. 31, 2024 USD ($) Director shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2025 USD ($) Director $ / shares shares	Dec. 31, 2024 USD ($) Director $ / shares shares	Dec. 31, 2023 shares	Dec. 31, 2022	Mar. 01, 2025	Mar. 01, 2024	Mar. 01, 2023	Dec. 31, 2021 shares	Dec. 31, 2019 shares
Stock-Based Compensation [Abstract]
Expected life of the options						5 years 7 months 6 days	5 years 8 months 12 days
Expected dividend yield used in the option valuation model						0.00%	0.00%
Closing price (in Dollars per share) \| $ / shares			$ 4.16			$ 4.16
Weighted-average grant-date fair values of options granted (in Dollars per share) \| $ / shares						$ 0.87	$ 1.26
Unvested option (in Shares)			335,001	716,504		335,001	716,504
Unrecognized compensation cost (in Dollars) \| $				$ 283,000			$ 283,000
Unrecognized compensation cost, recognition period						1 year
Options vested (in Shares)						1,255,418	1,966,167
Total fair value of options vested (in Dollars) \| $						$ 1,273,328	$ 2,772,748
Amortized expense (in Dollars) \| $						$ 1,656,000	$ 2,447,000
Restricted Stock [Member]
Stock-Based Compensation [Abstract]
Restricted stock awards granted (in Shares)	504,000	408,000				32,520	23,256
Restricted stock units valued at grant (in Dollars) \| $	$ 620,000	$ 734,000
Vesting percentage of Restricted Stock Units						100.00%	100.00%
Restricted stock awards vested (in Shares)						334,000
Number of Directors (in Director) \| Director			1	1		1	1
Amortized expense (in Dollars) \| $						$ 40,000	$ 40,000
Chief Executive Officer [Member]
Stock-Based Compensation [Abstract]
Unrecognized compensation cost (in Dollars) \| $			$ 0			$ 0
Minimum [Member]
Stock-Based Compensation [Abstract]
Award term						5 years
Expected life of the options						5 years
Maximum [Member]
Stock-Based Compensation [Abstract]
Award term						10 years
Expected life of the options						6 years
Deferred Bonus [Member] \| Chief Executive Officer [Member]
Stock-Based Compensation [Abstract]
Percentage of base salary paid in cash								20.00%	20.00%
Percentage of base salary paid in deferred stock units								80.00%	80.00%
Percentage of DSUs shall be credited on March 1, 2023									25.00%
Percentage of DSUs shall be credited on March 1, 2024									50.00%
Percentage of DSUs shall be credited on September 1, 2028									25.00%
Percentage of DSUs shall be credited on March 1, 2025/2024										50.00%	50.00%
Shares unissued (in Shares)			137,563	367,800	183,900	137,563	367,800	183,900
Shares withheld to cover income tax withholding (in Shares)			56,420	153,288	75,529
Income tax payment withholding (in Dollars) \| $			$ 88,579	$ 300,445	$ 156,345
Shares issued (in Shares)			81,144	214,512	108,371
Percentage of DSUs shall be credited on March 1, 2023												25.00%
Percentage of DSUs shall be credited on March 1, 2025					50.00%			50.00%
Percentage of DSUs shall be credited on January 5, 2026					50.00%			50.00%
Equity Incentive Plan 2019 [Member]
Stock-Based Compensation [Abstract]
Number of shares authorized for issuance (in Shares)					10,000,000			10,000,000					7,000,000	4,000,000
Stock awards, available for future grant (in Shares)				4,135,213			4,135,213
Incentive Compensation Plan 2009 [Member]
Stock-Based Compensation [Abstract]
Number of shares authorized for issuance (in Shares)				6,733,334			6,733,334