License and Collaboration Agreements - Additional Information (Detail)	1 Months Ended							3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	May 31, 2020 USD ($)	Apr. 30, 2020 USD ($)	Jul. 31, 2019	Nov. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2021 USD ($) ProductCandidate	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)	May 31, 2018 USD ($)
License Revenue [Line Items]
Milestone payment upon commencement of clinical trials in humans											$ 538,300,000
Milestone payment upon submission of regulatory approval filings											21,000,000.0
Milestone payment upon approval of commercial products by regulatory agencies											141,000,000.0
Milestone payment upon achievement of specified sales targets for licensed products											877,000,000.0
Accounts Receivable, after Allowance for Credit Loss											34,701,000	$ 46,266,000	$ 42,303,000		$ 31,599,000
Deferred revenue, current and non-current											3,333,000	4,232,000	3,333,000		$ 3,933,000
Provision for credit losses (recoveries)											(2,569,000)	7,678,000	0
Allowance for credit losses													0
License Revenue												3,500,000	3,500,000
Interest income from licensing											719,000	4,271,000	2,951,000
Accounts receivable, current											32,439,000	42,999,000
Accounts receivable (net of allowance of $3,758 as of December 31, 2021)											2,262,000	3,267,000
Abb Vie Global Enterprises Ltd
License Revenue [Line Items]
Accounts Receivable, after Allowance for Credit Loss											370,000,000.0
Novartis Gene Therapies [Member]
License Revenue [Line Items]
Accounts Receivable, after Allowance for Credit Loss												80,000,000.0
Interest income from licensing											22,000	26,000	29,000
Novartis Gene Therapies [Member] | March 2014 License Agreement [Member]
License Revenue [Line Items]
Milestone payment upon achievement of specified sales targets for licensed products										$ 1,000,000,000.0
Up-front fee paid							$ 2,000,000.0
License Fees						$ 180,000,000.0
Cumulative payments																$ 12,300,000
Sales based milestone payments receivable								$ 80,000,000.0	$ 80,000,000.0
Revenue Recognition, Milestone Method, Revenue Recognized										$ 80,000,000.0
License Revenue												3,500,000	3,500,000
Accounts receivable											26,600,000	19,600,000
Zolgensma Royalties [Member] | March 2014 License Agreement [Member]
License Revenue [Line Items]
Milestone payment upon achievement of specified sales targets for licensed products								$ 1,000,000,000.0	$ 1,000,000,000.0
Abeona Therapeutics Incorporation | Contract Termination
License Revenue [Line Items]
Up-front and annual fees					$ 20,000.0
Abeona Therapeutics Incorporation | November Two Thousand Eighteen License Agreement
License Revenue [Line Items]
Allowance for credit losses												7,700,000
Accounts receivable											30,100,000	30,100,000
License fee		$ 20,000,000.0	$ 8,000,000.0		$ 8,000.0
Abeona Therapeutics Incorporation | November Two Thousand Eighteen License Agreement | Contract Termination
License Revenue [Line Items]
Accounts receivable		$ 28,000.0									28,000.0			$ 33,600
Interest percentage on unpaid balances under license agreement					1.50%
License agreement termination claims, description		after the termination of the November 2018 License, Abeona filed a claim in arbitration alleging that the Company had breached certain responsibilities to communicate with Abeona regarding the Company’s prosecution of licensed patents under the November 2018 License. The Company disputed Abeona’s claim and filed a counterclaim in arbitration demanding payment of the $28.0 million of unpaid fees from Abeona, plus accrued interest.			As a result of the termination, Abeona was required to pay an additional $20.0 million license fee to the Company within 15 days of the termination date, which otherwise would have been due to the Company in November 2020.
Interest receivable		$ 5,600
Settlement agreement payable											30,000.0
Interest income from licensing												2,100,000
Abeona Therapeutics Incorporation | November Two Thousand Twenty One License Agreement | Contract Termination
License Revenue [Line Items]
Settlement agreement payable											20,000.0
Abeona Therapeutics Incorporation | November Two Thousand Twenty Two License Agreement | Contract Termination
License Revenue [Line Items]
Settlement agreement payable											5,000.0
Abeona Therapeutics Incorporation | November Two Thousand Twenty Four License Agreement | Contract Termination
License Revenue [Line Items]
Settlement agreement payable											5,000.0
Abeona Therapeutics Incorporation | Settlement Agreement
License Revenue [Line Items]
Allowance for credit losses											3,800,000
Accounts receivable											8,800,000
Cash acquired in excess of payments to acquire business											20,000,000.0
Accounts receivable, current											5,000,000.0
Accounts receivable (net of allowance of $3,758 as of December 31, 2021)											3,800,000
Payments due from related party											5,000,000.0
Provision for credit losses (recoveries)											(2,600,000)	7,700,000
Abb Vie Collaboration And License Agreement
License Revenue [Line Items]
Up-front fee paid	$ 370,000,000.0
Milestone fee payments upon achievement of various development and commercialization	1,380,000,000
Transaction price of license											370,000,000.0
Reimbursement of development costs											5,900,000
Abb Vie Collaboration And License Agreement | Development Milestone
License Revenue [Line Items]
Milestone fee payments upon achievement of various development and commercialization	562,500,000
Transaction price of license											562,500,000
Abb Vie Collaboration And License Agreement | Sales Based Milestones
License Revenue [Line Items]
Milestone fee payments upon achievement of various development and commercialization	$ 820,000,000.0
Transaction price of license											820,000,000.0
Neurimmune
License Revenue [Line Items]
Reimbursement of development costs											400,000	300,000
Period for sharing of research and development cost				2 years
Percentage of partnership in collaboration				50.00%
Neurimmune | Research and Development [Member]
License Revenue [Line Items]
Reimbursement of development costs											200,000	$ 300,000
Maximum [Member]
License Revenue [Line Items]
Aggregate milestone payment for all the targets											$ 1,580,000,000
Maximum [Member] | Neurimmune | Research and Development [Member]
License Revenue [Line Items]
Reimbursement of development costs													$ 100,000
N A V Technology Platform [Member]
License Revenue [Line Items]
Number of commercial product candidates | ProductCandidate											1
HCR [Member] | Novartis Gene Therapies [Member] | March 2014 License Agreement [Member]
License Revenue [Line Items]
Accounts receivable, current											$ 12,800,000