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Commitments and Contingencies - Additional Information (Detail)			3 Months Ended		12 Months Ended
	Aug. 12, 2022	Nov. 04, 2021 ft²	Mar. 31, 2024 USD ($) Milestone	Mar. 31, 2023 USD ($) Milestone	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Other Commitments [Line Items]
Rental expense			$ 100,000	$ 100,000
Remaining term of office lease			9 months
Debt outstanding			$ 0
Indemnification obligations amount			0
Contingent liabilities			$ 0
ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Fee due for milestones achieved								$ 1,000,000.0	$ 1,000,000.0
Common stock issued in lieu of making a cash payment								$ 1,000,000.0	$ 1,000,000.0
Number of Milestones Achieved | Milestone			0	0
Remaining milestone payments for first licensed product			$ 6,000,000.0
Annual License Maintenance Fee					$ 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
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
Maximum [Member]
Other Commitments [Line Items]
Remaining term of office lease			1 year
Maximum [Member] | ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Development and regulatory milestone payments			$ 2,500,000
Irvine, California [Member]
Other Commitments [Line Items]
Area of office space | ft²						5,197
Lease expiration date	Dec. 31, 2024
Burlington, Massachusetts [Member]
Other Commitments [Line Items]
Area of office space | ft²		6,138
Lease expiration date		Nov. 20, 2024

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