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Aggregate milestone payments upon achievement of specified one time regulatory development and commercial milestone events.

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Collaborative arrangement, number of research programs.

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Collaborative arrangement, term of agreement.

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Collaborative arrangement, up-front payment in next twelve months.

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Collaborative arrangement upfront non-refundable amount payable.

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Contra research and development expense.

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Number of licensed products.

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Regulatory milestone incurred based on achievement.

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Regulatory milestone payments based on achievement.

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Royalties entitled to receive after first commercial sale of applicable licensed product period.

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Royalty revenue.

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Sales milestone payments based on achievement of annual sales milestones.

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Sublicense fee owed.

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Upfront payment.

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Upfront payment to be received.

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Waived payment.

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License and Collaboration Agreements - Additional Information (Detail)		1 Months Ended										3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2020 USD ($)	Sep. 30, 2025 USD ($) License	Aug. 31, 2025 USD ($)	Jan. 31, 2024 USD ($)	Oct. 31, 2023 USD ($)	Apr. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Apr. 30, 2022 USD ($)	Aug. 31, 2021 USD ($)	Jun. 30, 2021 Program	Sep. 30, 2025 USD ($) License	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) License	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jul. 01, 2025 USD ($) Price	Jul. 31, 2021 USD ($)	Jan. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)
SYFOVRE [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone payments				$ 3,000,000	$ 2,000,000	$ 2,300,000
Royalty expense												$ 4,900,000	$ 4,900,000	$ 14,100,000	$ 14,400,000
Regulatory milestone incurred																$ 5,000,000
EMPAVELI and Aspaveli [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments based on annual sales milestones				1,500,000
Royalty expense												2,000,000	1,800,000	5,300,000	5,000,000
Swedish Orphan Biovitrum AB (Publ) [Member] \| Aspaveli [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty Revenue												600,000	5,000,000	12,600,000	13,900,000
Royalty Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment to be received																	$ 275,000,000
Aggregate amount agreed to be received upon European Medicines Agency approval																	$ 25,000,000
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									$ 50,000,000
Development cost reimbursement received														65,000,000
Waived Payment														$ 15,000,000
Royalties entitled to receive after first commercial sale of applicable licensed product period														10 years
Caps intial purchase price \| Price																	1.45
Percentage of royalty payment obligation																	90.00%
Percentage of royalty payment obligation reverted																	100.00%
Contract research and development expense												0	0	$ 0	0
Revenue recognized												5,200,000	$ 15,300,000	17,200,000	$ 36,200,000
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
Development cost reimbursement														80,000,000
University of Pennsylvania [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development milestone achievement										$ 1,000,000
Additional payment upon for sublicense fee related to collaboration agreement								$ 5,000,000
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										$ 3,200,000		3,200,000
Milestone payments based on annual sales milestones														$ 5,000,000
2010 License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of licensed products \| License		2										2		2
2010 License Agreement [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestones payments		$ 1,700,000										$ 1,700,000		$ 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				$ 500,000															$ 25,000,000
Research Collaboration Agreement [Member] \| Beam Therapeutics Incorporation [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
Neonatal Fc Receptor [Member[ \| Beam Therapeutics Incorporation [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment		$ 3,800,000
Neonatal Fc Receptor [Member[ \| Beam Therapeutics Incorporation [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment received for achievement of regulatory development milestone			$ 168,800,000
Milestone payments based on annual sales milestones			$ 215,000,000