v3.25.3

License and Collaboration Agreements - Servier (Details) $ in Thousands, € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 EUR (€)	May 10, 2024 EUR (€)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development \| $	$ 31,164	$ 44,713	$ 121,520	$ 147,327
Servier \| License and Collaboration Agreement \| UNITED STATES
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty rate, percent						10.00%
Reduction to royalty rate, percent						10.00%
Servier \| Sales Milestone \| License and Collaboration Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Aggregate milestone payments						€ 80.0
Servier \| Regulatory And Sales Milestones \| License and Collaboration Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development \| $	$ 0		$ 0
Servier \| Regulatory Milestone \| License and Collaboration Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Aggregate milestone payments						75.0
Aggregate potential milestone payments, remaining obligation						60.0
Milestone payable per indication						55.0
Collaborative arrangement, rights and obligations, aggregate milestone payments, per additional indication, remaining amount					€ 50.0
Aggregate potential milestone payable					€ 20.0	€ 20.0
Research and development \| $		$ 0		$ 5,400

Collaborative Arrangement, Rights And Obligations, Aggregate Milestone Payments, Per Additional Indication

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsAggregateMilestonePaymentsPerAdditionalIndication
Namespace Prefix:	allo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Collaborative Arrangement, Rights And Obligations, Aggregate Milestone Payments, Per Additional Indication, Remaining Amount

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsAggregateMilestonePaymentsPerAdditionalIndicationRemainingAmount
Namespace Prefix:	allo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Collaborative Arrangement, Rights And Obligations, Maximum Aggregate Milestone Payments

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsMaximumAggregateMilestonePayments
Namespace Prefix:	allo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Collaborative Arrangement, Rights And Obligations, Maximum Aggregate Milestone Payments Remaining

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsMaximumAggregateMilestonePaymentsRemaining
Namespace Prefix:	allo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Collaborative Arrangement, Rights And Obligations, Milestone Payable

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsMilestonePayable
Namespace Prefix:	allo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Collaborative Arrangement, Rights and Obligations, Royalties Payable, Annual Rate, Percent

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsRoyaltiesPayableAnnualRatePercent
Namespace Prefix:	allo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Collaborative Arrangement, Rights and Obligations, Royalties Payable, Annual Rate, Reduction, Percent

+ References

No definition available.

+ Details

Name:	allo_CollaborativeArrangementRightsAndObligationsRoyaltiesPayableAnnualRateReductionPercent
Namespace Prefix:	allo_
Data Type:	dtr-types:percentItemType
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/2003/role/disclosureRef
-Topic 730
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483041/730-20-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 730
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483041/730-20-50-1

+ Details

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

- Definition

Amount of expense for research and development. Includes, but is not limited to, cost for computer software product to be sold, leased, or otherwise marketed and writeoff of research and development assets acquired in transaction other than business combination or joint venture formation or both. Excludes write-down of intangible asset acquired in business combination or from joint venture formation or both, used in research and development activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-18

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-14

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 48
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-48

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 985
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481283/985-20-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 730
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482916/730-10-50-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 912
-SubTopic 730
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479532/912-730-25-1

+ Details

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

- Details

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

- Details

Name:	us-gaap_TypeOfArrangementAxis=allo_LicenseAndCollaborationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=allo_SalesMilestoneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=allo_RegulatoryAndSalesMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=allo_RegulatoryMilestoneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Allogene Therapeutics, Inc. 10-Q