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License, Collaboration, and Success Payment Agreements - Narrative (Details) | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2024 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2023 USD ($) | Oct. 31, 2020 USD ($) $ / shares | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) $ / shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Research and development expense | $ 43,174,000 | $ 44,630,000 |  |  |  |
Series A Convertible Preferred Stock |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Convertible preferred stock, par value (in dollars per share) | $ / shares |  |  |  | $ 1.83 |  | $ 1.83
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Annual license maintenance payments |  |  |  |  |  | $ 50,000
Aggregate research payments due |  |  |  |  |  | $ 12,000,000
Term of collaborative arrangement for research |  |  |  |  |  | 6 years
Research and development expense | 100,000 | 300,000 |  |  |  |
Aggregate success payments | 0 |  |  |  |  |
Term of success payment agreement |  |  |  |  |  | 9 years
Trigger period from IPO date |  |  |  |  |  | 1 year
Trigger period thereafter |  |  |  |  |  | 2 years
Fair value of potential success payments due | 1,100,000 |  | $ 700,000 |  |  |
Success payment expense (reversal) | 400,000 | (1,100,000) |  |  |  |
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Multiple of initial equity value at issuance |  |  |  |  |  | 10
Aggregate success payments |  |  |  |  |  | $ 10,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares |  |  |  |  |  | $ 18.29
Fred Hutch | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Multiple of initial equity value at issuance |  |  |  |  |  | 50
Aggregate success payments |  |  |  |  |  | $ 200,000,000
Per share common stock price required for payment (in dollars per share) | $ / shares |  |  |  |  |  | $ 91.44
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Annual license maintenance payments |  |  |  |  | $ 50,000 |
Aggregate research payments due |  |  |  | $ 12,000,000 |  |
Term of collaborative arrangement for research |  |  |  | 4 years |  |
Research and development expense | 800,000 | 800,000 |  |  |  |
Aggregate success payments | 0 |  |  |  |  |
Term of success payment agreement |  |  |  | 9 years |  |
Trigger period from IPO date |  |  |  | 1 year |  |
Trigger period thereafter |  |  |  | 2 years |  |
Fair value of potential success payments due | 1,700,000 |  | 1,100,000 |  |  |
Success payment expense (reversal) | 500,000 | $ (600,000) |  |  |  |
Success payment liability | $ 1,500,000 |  | $ 900,000 |  |  |
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | License |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Potential milestone payments due |  |  |  |  | 2,500,000 |
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Minimum |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Multiple of initial equity value at issuance |  |  |  | 10 |  |
Aggregate success payments |  |  |  | $ 10,000,000 |  |
Per share common stock price required for payment (in dollars per share) | $ / shares |  |  |  | $ 18.29 |  |
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Multiple of initial equity value at issuance |  |  |  | 50 |  |
Aggregate success payments |  |  |  | $ 200,000,000 |  |
Per share common stock price required for payment (in dollars per share) | $ / shares |  |  |  | $ 91.44 |  |
Stanford | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Maximum | License |  |  |  |  |  |
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] |  |  |  |  |  |
Potential milestone payments due |  |  |  |  | $ 3,700,000 |

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- Definition The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 730 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482916/730-10-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 912 -SubTopic 730 -Name Accounting Standards Codification -Section 25 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482517/912-730-25-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 985 -SubTopic 20 -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481283/985-20-50-1 + Details
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