Collaborations and Other Arrangements - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended	84 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Mar. 31, 2023	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs to obtain or fulfill contract capitalized	$ 0			$ 0
Collaboration revenue	12,606,000	$ 11,252,000
Deferred revenue	49,205,000	113,240,000	$ 63,771,000	49,205,000	$ 127,235,000
Collaboration agreement payment made	56,109,000
Revenue	2,800,000	2,800,000
Regeneron Pharmaceuticals Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate transaction price remaining to be recognized	23,300,000			23,300,000
Accounts receivable	4,200,000		3,200,000	4,200,000
Deferred revenue	23,300,000		28,800,000	23,300,000
Regeneron Pharmaceuticals Inc. [Member] | Hemophilia Co Co Agreements
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	2,900,000	1,500,000
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	$ 6,800,000	5,900,000		179,900,000
Aggregate transaction price remaining to be recognized, period	Through March 31, 2023
Payments due	$ 4,200,000	1,800,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member] | Research and Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	40,700,000
ONK Therapeutics [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable	100,000		100,000	100,000
ONK Therapeutics [Member] | Research Materials Shippmet Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	100,000	0
Kyverna Therapeutics Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable	0		0	0
Deferred revenue			400,000
Revenue	400,000	0
Sparing Vision [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	400,000	0
Accounts receivable	200,000		100,000	200,000
Deferred revenue	14,500,000		14,700,000	14,500,000
AvenCell [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions	2,800,000	2,800,000
Collaboration revenue	5,600,000	5,600,000
Accounts receivable	300,000		300,000	300,000
Deferred revenue	11,400,000		19,900,000	$ 11,400,000
AvenCell [Member] | AvenCell Co Co Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	$ 700,000	$ 200,000
AvenCell [Member] | Co-Development and Co-Funding Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration agreement payment made			$ 30,000,000.0