RELATED PARTY TRANSACTIONS - Related party contributions by member (Details) - USD ($) $ in Thousands		6 Months Ended
	Jun. 24, 2024	Jun. 30, 2025	Jun. 30, 2024
Related Party Transaction [Line Items]
Cash funding received from Illumina		$ 0	$ 1,244,300
Illumina, Inc.
Related Party Transaction [Line Items]
Cash funding received from Illumina	$ 932,300
Related Party \| Illumina, Inc.
Related Party Transaction [Line Items]
Cash funding received from Illumina			1,244,300
Total contributions from member, net			$ 1,244,300

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.

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+ Details

GRAIL, Inc. 10-Q