Investments and Other Assets - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Reclassification of other comprehensive income (loss) - equity method investment		$ 2,132,000
Investments and other assets	$ 46,788,000			$ 46,788,000		$ 42,883,000
Change in fair value of investments, net	(3,064,000)		$ 0	(29,483,000)	$ 0
Collaboration revenue	9,111,000		11,992,000	45,003,000	38,192,000
Accrued expenses	51,206,000			51,206,000		67,017,000
AvenCell Therapeutics, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Reclassification of other comprehensive income (loss) - equity method investment				2,100,000
Investments and other assets	9,600,000			9,600,000
Kyverna Therapeutics Inc [Member]
Schedule of Equity Method Investments [Line Items]
Investment Owned, Balance, Principal Amount	5,700,000			5,700,000
Change in fair value of investments, net	3,100,000			4,300,000
Investment Owned, Fair Value						10,000,000
Collaboration revenue	0			0
AvenCell [Member]
Schedule of Equity Method Investments [Line Items]
Change in fair value of investments, net				25,300,000
Investment Owned, Fair Value						11,800,000
Collaboration revenue	200,000		1,900,000	21,000,000	12,700,000
Accounts receivable	400,000			400,000		200,000
Accrued expenses	$ 1,000,000			$ 1,000,000		$ 1,000,000
AvenCell [Member] | AvenCell Therapeutics, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	33.33%			33.33%		33.33%
Collaboration revenue				$ 200,000
Sparing Vision [Member]
Schedule of Equity Method Investments [Line Items]
Investment Owned, Fair Value	$ 14,600,000			14,600,000
Collaboration revenue	$ 600,000		$ 400,000	$ 1,700,000	$ 1,300,000