License, Collaboration and Service Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands, £ in Millions			1 Months Ended						3 Months Ended				12 Months Ended
	Sep. 21, 2022 USD ($) $ / shares shares	Jan. 15, 2021 USD ($)	Oct. 31, 2021 USD ($)	Nov. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 GBP (£)	May 31, 2016 USD ($)	Dec. 31, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Feb. 28, 2025 USD ($)	Jan. 31, 2025 USD ($)	Oct. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)	Aug. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Feb. 29, 2024 USD ($)	Jul. 31, 2023 USD ($)	Nov. 07, 2022 USD ($)	Oct. 31, 2017 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total milestone										$ 95,000				$ 95,000
Deferred Revenue, Current									$ 368	2,132			$ 368	2,132
Revenue recognized													371	933
Proceeds from sale of common stock to related party													0	221
Common stock issued, aggregate fair value														221
GSK SPA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial Payments Amount to Perform the Obligations															$ 66,000
Discount on Performance of Obligations															1,300
Total milestone									30,000				30,000
Issuance of common stock, net of issuance costs, shares | shares	7,450,000
Common stock issued, aggregate fair value	$ 10,300
Remaining Transaction Price Allocated To Performance Obligations									64,700				64,700
Milestone payment									21,200				21,200
License and Know-How Transfer [Member] | GSK SPA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Remaining Transaction Price Allocated To Performance Obligations															64,700
Performance Obligation Allocated Transaction Price															45,700
Research And Development Services Related To Upcoming Milestones [Member] | GSK SPA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized															19,000
Cantab Related Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payment upon achievement of specified commercial milestone							£ 5.0						6,300
License agreement research and development expense related to achievement of regulatory milestones													$ 0	0
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones						$ 5,800
Vertex License Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract termination period													10 years
Nonrefundable upfront payments								$ 500
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones								$ 80,200
License agreement payment of research and development expense related to achievement of regulatory milestones													$ 0	0
Contract termination period if no material development or commercialization occurs													1 year
Meiji License Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Nonrefundable upfront payments					$ 600
Sublicense fee payable to counter party															7,500
Sublicence Fee Paid															$ 6,600
Potential milestone payments upon achievement of specified condition																											$ 1,000
License agreement fixed assets related payments												$ 1,600
Remaining Sublicence Fee Paid to Counter Party										900				900
Potential milestone payments upon completion and delivery of results of a clinical study			$ 1,000
Future milestone payments													$ 1,000
Everest License Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Period of option granted on an agreement													12 months
Revenue recognized													$ 0	0
Milestone payment									34,000				34,000
Everest License Agreement [Member] | SPR206 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payment received		$ 2,000
Everest License Agreement [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement termination period upon written notice		180 days
Everest License Agreement [Member] | Maximum [Member] | SPR206 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receivable amount upon achievement of certain milestone		$ 38,000							59,500				59,500
Everest License Agreement [Member] | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement termination period upon written notice		90 days
Pfizer License and Share Purchase Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Receivable amount upon achievement of certain milestone											$ 900
Milestones payment received											5,000
Deferred Revenue, Current									12,600				12,600
Revenue recognized													400	900
Common stock issued, aggregate fair value													27,500
Associated premium as a freestanding equity-linked instrument under ASC 815													12,500
Remaining Transaction Price Allocated To Performance Obligations									$ 12,500				12,500
Performance Obligation Allocated Transaction Price											5,000
Pfizer License and Share Purchase Agreements [Member] | SPR206 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment received													$ 0
Issuance of common stock, net of issuance costs, shares | shares													2,362,348
Share price | $ / shares									$ 16.93				$ 16.93
Proceeds from sale of common stock to related party													$ 40,000
Receivable amount upon achievement of certain milestone													80,000
Pfizer License and Share Purchase Agreements [Member] | License and Know-How Transfer [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance Obligation Allocated Transaction Price													1,400
Pfizer License and Share Purchase Agreements [Member] | Research And Development Services Related To Upcoming Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Performance Obligation Allocated Transaction Price											$ 4,100		11,100
Savior Service Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses										5,300				5,300
Savior Service Agreement [Member] | Prepaid Expenses and Other Current Assets [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable supervision fee related to commercial manufacturing facility				$ 2,000
Savior Service Agreement [Member] | Long-term Asset [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Service agreement additional payment related to facility build out costs				$ 5,300
GSK License Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred Revenue, Current									$ 22,300				22,300
Issuance of common stock, net of issuance costs, shares | shares	7,450,000
Share price | $ / shares	$ 1.2
Common stock issued, aggregate fair value	$ 1,300
Milestone payment									225,000				225,000
Performance Obligation Allocated Transaction Price													27,000	95,800
Remaining milestone payment													1,100
GSK License Agreement [Member] | Glaxo Smith Kline [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																$ 23,800						$ 23,800		$ 23,800		$ 66,000
Change in subsequent payments																										50.00%
GSK License Agreement [Member] | Glaxo Smith Kline [Member] | Amendment 2 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																									$ 4,300
GSK License Agreement [Member] | Glaxo Smith Kline [Member] | Amendment 4 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																				$ 800
GSK License Agreement [Member] | GSK SPA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total milestone										95,000				95,000
Milestone Achievement Research And Development Services										64,700				64,700
Milestone payment																$ 23,800	$ 23,800				$ 23,800		$ 23,800		$ 30,000
Milestone payment received									30,000	95,000			30,000	95,000
Significant financing component										2,500
Milestone Allocated Research And Development Services									8,800	$ 2,500			8,800	$ 2,500
GSK License Agreement [Member] | First Milestone [Member] | Amendment 2 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																						$ 1,200
GSK License Agreement [Member] | Second Milestone [Member] | Glaxo Smith Kline [Member] | Amendment 2 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																				$ 1,300
GSK License Agreement [Member] | Second Milestone [Member] | GSK SPA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment received																			$ 400
GSK License Agreement [Member] | Third Milestone [Member] | Glaxo Smith Kline [Member] | Amendment 2 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment																		$ 700
GSK License Agreement [Member] | Research And Development Services Related To Upcoming Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone Allocated Research And Development Services									4,300				4,300
Total potential additional milestones									$ 3,200				$ 800