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Significant Agreements - Additional Information (Details) |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |
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Aug. 04, 2023 | Aug. 01, 2023 USD ($) | Dec. 16, 2021 USD ($) | Dec. 16, 2021 USD ($) ft² | Dec. 16, 2021 USD ($) OfficeSuite | Jun. 18, 2021 shares | Jun. 07, 2021 USD ($) | Apr. 30, 2021 USD ($) | Jan. 31, 2021 USD ($) shares | Dec. 31, 2020 USD ($) shares | Sep. 30, 2023 USD ($) shares | Jun. 30, 2023 shares | Sep. 30, 2022 USD ($) | Sep. 30, 2023 USD ($) shares | Sep. 30, 2022 USD ($) | Dec. 31, 2022 USD ($) shares | Dec. 31, 2021 USD ($) shares | Dec. 31, 2020 USD ($) shares | May 07, 2021 shares
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares, issued | shares |  |  |  |  |  |  |  |  |  |  | 57,971,910 |  |  | 57,971,910 |  | 58,221,760 | 58,010,823 |  |
Research and development |  |  |  |  |  |  |  |  |  |  | $ 2,384,000 |  | $ 18,302,000 | $ 32,136,000 | $ 54,325,000 | $ 72,787,000 | $ 37,932,000 |  |
General and administrative |  |  |  |  |  |  |  |  |  |  | 11,294,000 |  | 7,852,000 | 26,372,000 | 24,563,000 | 32,852,000 | 22,511,000 |  |
Option agreement fees paid |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Options fee |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Future minimum lease payments |  |  |  |  |  |  |  |  |  |  | 86,487,000 |  |  | 86,487,000 |  | 6,174,000 |  |  |
Operating lease liability |  |  |  |  |  |  |  |  |  |  | 53,111,000 |  |  | 53,111,000 |  | 5,794,000 |  |  |
Contingencies Recorded |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock shares, repurchase | shares |  |  |  |  |  |  |  |  |  |  |  | 152,694 |  |  |  |  |  |  |
Stanford Exclusive License Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Upfront license fees received |  |  |  |  |  |  |  |  |  | $ 50,000 |  |  |  |  |  |  |  |  |
Common stock, shares, issued | shares |  |  |  |  |  |  |  |  |  | 640,861 |  |  |  |  |  |  |  | 640,861 | 640,861
Common stock additional paid in capital |  |  |  |  |  |  |  |  |  | $ 2,800,000 |  |  |  |  |  |  |  | $ 2,800,000 |
Purchase of shares in private financings percentage |  |  |  |  |  |  |  |  |  | 10.00% |  |  |  |  |  |  |  |  |
Common stock shares, repurchase | shares |  |  |  |  |  | 624,845 |  |  |  |  |  |  |  |  |  |  |  |  |
Research and development |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,800,000 |
General and administrative |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 200,000 |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
First commercial sale |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50,000 |
Subsequent year commercial sale |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 200,000 |
Maximum future development and regulatory milestone payments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,300,000 |  |  |
Sale-based milestone payments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7,500,000 |  |  |
Milestone payments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |
License execution fee |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  |
Maximum future development and regulatory milestones payments |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,300,000 |  |  |  |  |
Sale-based milestones payments |  |  |  |  |  |  |  |  |  |  |  |  |  | 7,500,000 |  |  |  |  |
Stanford Exclusive License Agreement | Patents Fees Member |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General and administrative |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |
Stanford Exclusive License Agreement | First Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,000 |
Stanford Exclusive License Agreement | Second Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,000 |
Stanford Exclusive License Agreement | Third Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,000 |
Stanford Exclusive License Agreement | Fourth Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25,000 |
Stanford Exclusive License Agreement | Fifth Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25,000 |
Stanford Exclusive License Agreement | Sixth Year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25,000 |
License Agreement with Stanford | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock shares, repurchase | shares |  |  |  |  |  | 624,845 |  |  |  |  |  |  |  |  |  |  | (624,845) |  |
First Option Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares, issued | shares |  |  |  |  |  |  |  |  | 132,137 |  |  |  |  |  |  |  |  |  |
License execution fee |  |  |  |  |  |  |  |  | $ 10,000 |  |  |  |  |  |  |  |  |  |
Option agreement expiration term |  |  |  |  |  |  |  |  | 18 months |  |  |  |  |  |  |  |  |  |
Second Option Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual maintenance fees |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,000 |  |  |
Options fee |  |  |  |  |  |  |  | $ 30,000 |  |  |  |  |  |  |  |  |  |  |
LCGM Service Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research and development |  |  |  |  |  |  |  |  |  |  |  |  | 1,700,000 | 1,100,000 | 4,500,000 | 6,100,000 | $ 2,700,000 |  |
IDT License Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research and development |  |  |  |  |  |  |  |  |  |  | 0 |  |  | 0 |  | 0 | 3,000,000 |  |
Milestone payments |  |  |  |  |  |  |  |  |  |  | 0 |  | 0 | 0 | 0 | 0 | 0 |  |
Option agreement fees paid |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Exercise fee |  |  |  |  |  |  | $ 500,000 |  |  |  |  |  |  |  |  |  |  |  |
Upfront payment |  |  |  |  |  |  | 3,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Milestones probable |  |  |  |  |  |  |  |  |  |  | 0 |  | $ 0 | 0 | $ 0 |  |  |  |
IDT License Agreement | Research and Development Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total consideration |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,000,000 |  |
IDT License Agreement | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Upfront payment |  |  |  |  |  |  | 5,300,000 |  |  |  |  |  |  |  |  |  |  |  |
IDT License Agreement | Beta Thalassemia and Lysosomal Storage Disorders Fields |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exercise fee |  |  |  |  |  |  | 1,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Upfront payment |  |  |  |  |  |  | $ 8,800,000 |  |  |  |  |  |  |  |  |  |  |  |
Bayside Lease |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tenant improvement allowance |  |  |  |  |  |  |  |  |  |  |  |  |  | 14,900,000 |  | 14,900,000 |  |  |
Milestones probable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 | 0 |  |
Lease commencement date |  |  | Sep. 15, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Office and Laboratory Space |  |  |  | 85,165 | 85,165 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lease term |  |  | 120 months | 120 months | 120 months |  |  |  |  |  |  |  |  |  |  |  |  |  |
Security deposit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,600,000 | 1,600,000 |  |
Future minimum lease payments |  |  | $ 81,000,000 | $ 81,000,000 | $ 81,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Term of contract |  |  | 10 years | 10 years | 10 years |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating lease liability |  |  |  |  |  |  |  |  |  |  | 32,000,000 |  |  | 32,000,000 |  | 0 | $ 0 |  |
Tenant Improvements |  |  |  |  |  |  |  |  |  |  | 12,200,000 |  |  | 12,200,000 |  | $ 12,200,000 |  |  |
Asset Purchase Agreement (APA) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Milestone payments |  | $ 1,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exchange Amount Of Asset |  | 500,000 |  |  |  |  |  |  |  |  |  |  |  | 500,000 |  |  |  |  |
Loss on Disposal Other Income |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,000 |  |  |  |  |
Contingencies Recorded |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  | 0 |  |  |  |  |
Reimbursement of Research and Development Amount |  | $ 600,000 |  |  |  |  |  |  |  |  |  |  |  | $ 600,000 |  |  |  |  |
LOA to Acquire Nula-Cel Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Interest Outstanding Shares | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
LOA to Acquire Nula-Cel Assets | License And Option Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research And Development Arrangement Contract To Perform For Others [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Interset | 20.00% |  |  |  |  |  |  |  |  |  | 20.00% |  |  | 20.00% |  |  |  |  |

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