GOVERNMENT GRANTS (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Government Grants [Abstract]
Deferred government grants	$ 7,373	$ 8,110
Current	68	451
Non-current	$ 7,305	$ 7,659

The amount of current government grants recognised in the statement of financial position as deferred income. [Refer: Government [member]; Government grants]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_55&doctype=Standard
-URIDate 2023-03-23

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of assistance by government in the form of transfers of resources to an entity in return for past or future compliance with certain conditions relating to the operating activities of the entity, recognised as deferred income. They exclude those forms of government assistance that cannot reasonably have a value placed upon them and transactions with government that cannot be distinguished from the normal trading transactions of the entity. [Refer: Deferred income other than contract liabilities; Government [member]]

+ References

+ Details

Name:	ifrs-full_GovernmentGrants
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of non-current government grants recognised on the statement of financial position as deferred income. [Refer: Government [member]; Government grants]

+ References

+ Details

Name:	ifrs-full_NoncurrentGovernmentGrants
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Government grants.

+ References

No definition available.

+ Details

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Namespace Prefix:	legn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration