STOCK-BASED COMPENSATION - 2024 ESPP (Details) - Employee stock purchase plan - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Jan. 01, 2025 |
Sep. 30, 2025 |
Sep. 30, 2024 |
Sep. 30, 2025 |
Sep. 30, 2024 |
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| Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] | |||||
| Unrecognized share based compensation costs related to ESPP | $ 0.6 | $ 0.6 | |||
| Period for recognition of share-based compensation | 1 month 6 days | ||||
| The GRAIL, Inc. 2024 Employee Stock Purchase Plan | |||||
| Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] | |||||
| Additional shares authorized (in shares) | 338,934 | ||||
| Number of shares authorized (in shares) | 752,955 | ||||
| Shares available for grant (in shares) | 752,955 | 752,955 | |||
| Maximum earnings withheld for purchase of shares (as a percent) | 15.00% | ||||
| Purchase price as a percentage of fair value (as a percent) | 85.00% | ||||
| Shares granted (in shares) | 0 | 0 | 0 | 0 | |
| Expected dividend rate (as a percent) | 0.00% | ||||
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- Definition Employee Stock Purchase Plan, Maximum Earnings WIthheld Per Employee, Percent No definition available.
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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- 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). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Number of additional shares authorized for issuance under share-based payment arrangement. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Number of shares authorized for issuance under share-based payment arrangement. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Purchase price of common stock expressed as a percentage of its fair value. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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