v3.26.3
Segment Information - Schedule of Reportable Segment Profit and Loss, Including Significant Expense Categories, Attributable to the Company's Reportable Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Jun. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2026
Sep. 30, 2025
Revenues [Abstract]                
Total revenue $ 12,669     $ 889     $ 24,308 $ 2,646
Operating Expenses [Abstract]                
Research and development 71,888     58,902     207,614 201,280
Acquired in-process research and development             1,648 96,253
General and administrative expense 17,867     16,931     52,603 55,143
Collaboration expense, net 41,284     57,115     127,505 159,777
Stock-based compensation expense             51,601 54,423
Depreciation expense 4,200     4,400     12,800 13,800
Segment net loss             (325,522) (450,986)
Net loss (111,437) $ (91,154) $ (122,931) (106,441) $ (208,549) $ (135,996) (325,522) (450,986)
Sirius [Member]                
Operating Expenses [Abstract]                
Acquired in-process research and development 11,700           14,100  
Collaboration Revenue [Member]                
Revenues [Abstract]                
Total revenue 12,323     0     23,323 0
Grant Revenue [Member]                
Revenues [Abstract]                
Total revenue 346     889     985 2,646
Operating Segments [Member] | Business of Discovering , Developing and Commercializing Therapies [Member]                
Operating Expenses [Abstract]                
Research and development [1],[2] 56,231     48,298     166,967 167,863
Acquired in-process research and development [1],[3] 11,675     0     14,148 96,253
General and administrative expense [1],[4] 5,898     5,749     18,450 19,106
Stock-based compensation expense [1] 17,961     16,604     51,601 54,423
Depreciation expense [1] 4,238     4,415     12,819 13,764
Other segment items [1],[5] (18,608)     (25,618)     (52,040) (58,821)
Segment net loss (111,437)     (106,441)     (325,522) (450,986)
Adjustments or reconciling items 0     0     0 0
Net loss (111,437)     (106,441)     (325,522) (450,986)
Operating Segments [Member] | Vertex [Member] | Business of Discovering , Developing and Commercializing Therapies [Member]                
Operating Expenses [Abstract]                
Collaboration expense, net [1],[6] 41,284     57,115     127,505 159,777
Operating Segments [Member] | Sirius [Member] | Business of Discovering , Developing and Commercializing Therapies [Member]                
Operating Expenses [Abstract]                
Collaboration expense, net [1],[7] 5,427     767     10,380 1,267
Operating Segments [Member] | Collaboration Revenue [Member] | Business of Discovering , Developing and Commercializing Therapies [Member]                
Revenues [Abstract]                
Total revenue 12,323     0     23,323 0
Operating Segments [Member] | Grant Revenue [Member] | Business of Discovering , Developing and Commercializing Therapies [Member]                
Revenues [Abstract]                
Total revenue $ 346     $ 889     $ 985 $ 2,646
[1]

(1) The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM.
[2]

(2) Research and development expense for the three and nine months ended September 30, 2026 excludes $8.1 million and $23.8 million of stock-based compensation expense, respectively, and $2.1 million and $6.5 million of depreciation expense, respectively. Research and development expense for the three and nine months ended September 30, 2025 excludes $7.6 million and $25.1 million of stock-based compensation expense, respectively, and $2.3 million and $7.0 million of depreciation expense, respectively. Research and development expense for the periods presented also excludes costs related to the Sirius Agreement, described further below.
[3]

(3) Acquired in-process research and development expense for the three and nine months ended September 30, 2026 was $11.7 million and $14.1 million, respectively, and primarily consisted of a development milestone under the Sirius Agreement that was recognized in the third quarter of 2026. Acquired in-process research and development expenses for the nine months ended September 30, 2025 were attributable to the costs incurred upon entering the Sirius Agreement during the second quarter of 2025, as described in Note 6.
[4]

(4) General and administrative expense for the three and nine months ended September 30, 2026 excludes $9.8 million and $27.8 million of stock-based compensation expense, respectively, and $2.1 million and $6.4 million of depreciation expense, respectively. General and administrative expense for the three and nine months ended September 30, 2025 excludes $9.0 million and $29.3 million of stock-based compensation expense, respectively, and $2.2 million and $6.7 million of depreciation expense, respectively.
[5]

(7) Other segment items include interest income (expense), net, the change in fair value of corporate equity securities and income tax expense.
[6]

(5) Collaboration costs specific to the Vertex Hemoglobinopathy Agreements (as defined in Note 6) accounted for under ASC 808 are presented within “collaboration expense, net” in the condensed consolidated statements of operations and comprehensive loss.
[7]

(6) In the second quarter of 2025, the Company entered into the Sirius Agreement (as defined in Note 6). Collaboration costs, net of reimbursements, related to the Sirius Collaboration Products under the Sirius Agreement are presented within “research and development expense” in the condensed consolidated statements of operations and comprehensive loss. In the first quarter of 2026, the significant expense categories reviewed by the CODM were updated to include collaboration costs, net of reimbursements, associated with the Sirius Collaboration Products. As a result, the Company recast segment amounts for the three and nine months ended September 30, 2025 to reflect the updated significant expense categories.