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Commitments and Contingencies - Additional Information (Detail)			3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 12, 2022	Nov. 04, 2021 ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) ft² Milestone	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) Milestone	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)
Other Commitments [Line Items]
Rental expense			$ 100,000	$ 100,000	$ 300,000	$ 200,000
Effective date of lease amendment	Jan. 01, 2023
Remaining term of office lease					27 months
Indemnification obligations amount			0		$ 0
Contingent Liabilities			0		$ 0
Office of Chief Scientist of Israeli Ministry of Economy and Industry [Member]
Other Commitments [Line Items]
Grants received										$ 500,000
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		$ 6,000,000.0
Annual License Maintenance Fee							$ 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
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					5,197
Lease expiration date					Dec. 31, 2022
Burlington, Massachusetts [Member]
Other Commitments [Line Items]
Area of office space | ft²		6,138
Lease expiration date		Nov. 20, 2024

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