License and Collaboration Agreements - Additional Information (Detail)			1 Months Ended											12 Months Ended
	Nov. 30, 2020 USD ($)	Oct. 27, 2020 USD ($)	Jan. 31, 2024 USD ($)	Nov. 30, 2023 USD ($)	Oct. 31, 2023 USD ($)	Apr. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Apr. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Aug. 31, 2021 USD ($)	Jun. 30, 2021 Program	Jan. 31, 2021 USD ($)	Dec. 31, 2023 USD ($) License	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalties receivable														$ 3,054,000	$ 1,442,000
Accrued expenses														127,806,000	95,139,000
Subsequent Event [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development cost reimbursement received			$ 15,000,000
SYFOVRE [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty expense incurred														8,900,000
Regulatory milestone payments				$ 2,000,000		$ 2,300,000
Regulatory milestone incurred														5,000,000
Regulatory milestone accrued														3,000,000
Empaveli And Aspaveli [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty expense incurred														7,900,000
Accrued expenses														1,500,000
Swedish Orphan Biovitrum AB (Publ) [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development cost reimbursement		$ 80,000,000
Non-refundable Upfront Payment		250,000,000
Royalty revenue														$ 10,000,000
Collaboration and License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development cost reimbursement																$ 80,000,000
Collaboration and License Agreement [Member] | License [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment																$ 250,000,000
Collaboration and License Agreement [Member] | Swedish Orphan Biovitrum AB (Publ) [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 250,000,000
Milestone payment received for achievement of regulatory development milestone					$ 5,000,000				$ 50,000,000
Development cost reimbursement													$ 80,000,000
Development cost reimbursement received							$ 20,000,000			$ 20,000,000			25,000,000
Royalties entitled to receive after first commercial sale of applicable licensed product period														10 years
Royalty revenue															3,000,000
Royalties received														$ 10,000,000
Contract research and development expense														0	5,000,000
Remaining reimbursement payment			15,000,000
Contract research and development reimbursement commitment		80,000,000
Contract research and development current														15,000,000
Contract research and development receivable															35,000,000
Contract research and development receivable other current assets															20,000,000
Contract research and development receivable other assets															$ 15,000,000
Proceeds from contract research and development							20,000,000
Collaboration and License Agreement [Member] | Swedish Orphan Biovitrum AB (Publ) [Member] | Subsequent Event [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Remaining reimbursement payment			$ 15,000,000
Collaboration and License Agreement [Member] | Swedish Orphan Biovitrum AB (Publ) [Member] | ASC Topic 808
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 250,000,000.0
Development cost reimbursement		80,000,000.0
Collaboration and License Agreement [Member] | Swedish Orphan Biovitrum AB (Publ) [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone payments upon achievement of specified one time regulatory development and commercial milestone events																		$ 915,000,000
Collaboration and License Agreement [Member] | Swedish Orphan Biovitrum AB (Publ) [Member] | Maximum [Member] | ASC Topic 808
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone payments upon achievement of specified one-time regulatory and commercial milestone events		$ 915,000,000.0
University of Pennsylvania [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Annual maintenance fees														100,000
Development milestone achievement								$ 5,000,000			$ 1,000,000.0
University of Pennsylvania [Member] | Empaveli And Aspaveli [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments based on annual sales milestones							$ 1,000,000
University of Pennsylvania [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestones payments														3,200,000
Milestone payments based on annual sales milestones														5,000,000.0
2010 License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Annual maintenance fees														$ 100,000
Number of licensed products | License														2
2010 License Agreement [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestones payments														$ 1,700,000
Milestone payments based on annual sales milestones														2,500,000
Sobi Agreement and Another Licensing Transaction [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense fee owed													$ 25,000,000.0	$ 500,000
Research Collaboration Agreement [Member] | Beam [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement term												5 years
Number of research programs | Program												6
Up-front non-refundable payment																	$ 50,000,000
Up-front payment on first anniversary of agreement on June 30, 2022								$ 25,000,000
Collaboration agreement maximum extendable term								2 years