v3.25.4
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)
$ in Thousands
12 Months Ended
Jun. 24, 2024
USD ($)
Jan. 01, 2023
USD ($)
Dec. 31, 2025
USD ($)
financial_institution
segment
reporting_unit
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Cash and Cash Equivalents [Line Items]          
Number of financial institutions | financial_institution     3    
Cash and cash equivalents     $ 249,727 $ 214,234 $ 97,287
Short-term marketable securities     654,703 549,236  
Allowance for credit losses     $ 3,600 3,800  
Number of reporting units | reporting_unit     1    
Number of operating segments | segment     1    
Deferred revenue     $ 1,900 1,600  
Advertising costs     $ 15,100 17,700 $ 21,900
Expected dividend yield (as a percent)     0.00%    
Percent match of employee contribution   100.00%      
Maximum amount match, per employee   $ 3      
Defined contribution plan, employer contribution     $ 2,600 3,900  
Recognition of deferred tax liability in connection with the Spin-Off [1]       $ (447,190)  
Minimum | The GRAIL, Inc. 2024 Incentive Award Plan          
Cash and Cash Equivalents [Line Items]          
Vesting term (in years)     18 months    
Maximum | The GRAIL, Inc. 2024 Incentive Award Plan          
Cash and Cash Equivalents [Line Items]          
Vesting term (in years)     48 months    
Trade Names          
Cash and Cash Equivalents [Line Items]          
Identifiable intangible assets, estimated useful life     9 years    
Developed Technologies          
Cash and Cash Equivalents [Line Items]          
Identifiable intangible assets, estimated useful life     18 years    
Additional Paid in Capital          
Cash and Cash Equivalents [Line Items]          
Recognition of deferred tax liability in connection with the Spin-Off $ 447,200        
Illumina, Inc.          
Cash and Cash Equivalents [Line Items]          
Deferred capitalized R&D $ 447,200        
One Customer | Customer Concentration Risk | Revenue Benchmark          
Cash and Cash Equivalents [Line Items]          
Concentration risk, percentage (as a percent)     0.00% 11.00% 14.00%
One Customer | Customer Concentration Risk | Accounts Receivable          
Cash and Cash Equivalents [Line Items]          
Concentration risk, percentage (as a percent)     0.00% 32.00%  
[1]
*See Note 1 — Organization And Description Of Business for more information on the Spin-Off.