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License, Clinical Trial and Sponsored Research Agreements (Ongoing, Terminated Clinical Trial and Sponsored Research Agreements) (Narrative) (Details) - USD ($) $ in Thousands |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 03, 2017 | Jun. 30, 2024 | Apr. 30, 2024 | Nov. 30, 2022 | Jan. 31, 2022 | Nov. 30, 2020 | Oct. 31, 2020 | Feb. 28, 2017 | Dec. 31, 2024 | Dec. 31, 2023
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  |  |  |  |  |  | $ 7,557 | $ 40,513
Research and development |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Forgiveness of all amounts previously owed |  |  |  |  |  |  |  |  | $ 900 |
Mayo Clinic |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Forgiveness of all amounts previously owed |  | $ 300 |  |  |  |  |  |  |  |
St. Jude Children's Research Hospital - XSCID |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Forgiveness of all amounts previously owed |  |  | $ 600 |  |  |  |  |  |  |
IL13Ra2 CAR and (C134) |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Research and development expense |  |  |  | $ 600 |  |  | $ 300 |  |  |
Clinical trial and sponsored research agreements | IL13R2 (MB-101) | City of Hope National Medical Center |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Contribution toward patient costs |  |  |  |  |  |  |  | $ 100 |  |
Contribution per patient |  |  |  |  |  |  | 100 |  |  |
Annual maintenance fee payable |  |  |  |  |  |  | $ 200 |  |  |
Clinical trial and sponsored research agreements | CD20 (MB-106) | Fred Hutchinson Cancer Center |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Contribution toward patient costs |  |  |  |  |  | $ 800 |  |  |  |
Milestones payable | $ 5,300 |  |  |  |  |  |  |  |  |
Additional milestone payments |  |  |  |  | $ 2,200 | $ 1,800 |  |  |  |
Clinical trial and sponsored research agreements | CD20 (MB-106) | Fred Hutchinson Cancer Center | Maximum |  |  |  |  |  |  |  |  |  |
License, Clinical Trial and Sponsored Research Agreements |  |  |  |  |  |  |  |  |  |
Additional milestone payments |  |  |  |  | $ 9,300 |  |  |  |  |

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