Collaborations and Other Arrangements - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended			81 Months Ended
	Feb. 12, 2022	Sep. 30, 2021	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs to obtain or fulfill contract capitalized				$ 0			$ 0
Common stock, par value				$ 0.0001	$ 0.0001		$ 0.0001
Collaboration revenue				$ 52,121,000	$ 33,053,000	$ 57,994,000
Business Combination Consideration Transferred 1				56,109,000
Deferred revenue				63,771,000	127,235,000	73,931,000	$ 63,771,000
Revenue				11,400,000	2,900,000
Regeneron Pharmaceuticals Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate transaction price remaining to be recognized				28,800,000			28,800,000
Accounts receivable				3,200,000	2,000,000.0		3,200,000
Deferred revenue				28,800,000	51,400,000		28,800,000
Regeneron Pharmaceuticals Inc. [Member] | Hemophilia Co Co Agreements
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				10,400,000	2,700,000	0
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions							145,000,000.0
Collaboration revenue				$ 24,100,000	25,700,000	53,000,000.0	173,100,000
Aggregate transaction price remaining to be recognized, period				Through December 31, 2022
Payments due				$ 11,900,000	5,900,000	$ 10,700,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member] | Research and Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue							39,500,000
Novartis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue		$ 300,000	$ 5,000,000.0
Novartis [Member] | AvenCell Co/Co Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue				0	0		0
ONK Therapeutics [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development and commercial milestone payment to be received	$ 184,000,000
ONK Therapeutics [Member] | Research Materials Shippmet Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				100,000
Kyverna [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				400,000	7,000,000.0
Accounts receivable				0	0		0
Revenue				6,600,000	0
Sparing Vision [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				200,000	0
Accounts receivable				100,000	0		100,000
Deferred revenue				14,700,000	14,800,000		14,700,000
AvenCell Member
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions				11,400,000	2,900,000
Collaboration revenue				22,800,000	5,900,000
Accounts receivable				300,000	100,000		300,000
Deferred revenue				19,900,000	54,100,000		$ 19,900,000
AvenCell Member | Research Materials Shippmet Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				300,000
AvenCell Member | AvenCell Co/Co Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				$ 2,000,000.0	200,000
AvenCell Member | Co-development and co-funding agreement member
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Business Combination Consideration Transferred 1					$ 30,000,000.0