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Commitments and Contingencies - Additional Information (Detail)				3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 04, 2024 ft²	Apr. 19, 2024 USD ($) ft²	Aug. 12, 2022	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) Milestone	Jun. 30, 2024 USD ($) Milestone	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) ft²	Dec. 31, 2021 USD ($)	Nov. 21, 2024 USD ($)	May 31, 2015 USD ($)
Other Commitments [Line Items]
Non-cancelable purchase obligations related to manufacturing				$ 6,600,000		$ 6,600,000
Rental expense				100,000	$ 100,000	200,000	$ 200,000
Lease liabilities				803,000		803,000		$ 954,000
ROU assets				773,000		$ 773,000		926,000
Remaining term of office lease						3 years
Debt outstanding				0		$ 0
Indemnification obligations amount				0		0
Contingent liabilities				0		$ 0
ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Fee due for milestones achieved													$ 1,000,000
Number of Milestones Achieved | Milestone						0	0
Remaining milestone payments for first licensed product				6,000,000.0		$ 6,000,000.0
Annual License Maintenance Fee								$ 100,000	$ 100,000	$ 100,000	$ 100,000
ALS Therapy Development Foundation, Inc. License Agreement [Member] | Achievement of 500 Million Aggregate Sales [Member]
Other Commitments [Line Items]
Reaching of aggregate net sales						500,000,000.0
Amount of one-time milestone payment				15,000,000.0		15,000,000.0
ALS Therapy Development Foundation, Inc. License Agreement [Member] | Achievement of 1 Billion Aggregate Sales [Member]
Other Commitments [Line Items]
Reaching of aggregate net sales						1,000,000,000.0
Amount of one-time milestone payment				30,000,000.0		30,000,000.0
eGenesis, Inc. Collaboration Agreement [Member]
Other Commitments [Line Items]
Manufacturing expenses offset						100,000
Lonza Sales AG Inc. License Agreement
Other Commitments [Line Items]
Royalties paid						0
Maximum [Member] | ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Development and regulatory milestone payments				$ 2,500,000		$ 2,500,000
Irvine, California [Member]
Other Commitments [Line Items]
Area of office space | ft²		5,817								5,197
Operating lease, term of contract		38 months
Lease expiration date		Jun. 30, 2027	Dec. 31, 2024
ROU assets		$ 500,000
Burlington, Massachusetts [Member]
Other Commitments [Line Items]
Area of office space | ft²	6,138
Operating lease, term of contract	36 months
Lease expiration date	Nov. 21, 2027
Lease liabilities												$ 500,000
ROU assets												$ 500,000

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