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Maximum future development and commercial milestone payments receivable.

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- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of expense for research and development. Includes, but is not limited to, cost for computer software product to be sold, leased, or otherwise marketed and writeoff of research and development assets acquired in transaction other than business combination or joint venture formation or both. Excludes write-down of intangible asset acquired in business combination or from joint venture formation or both, used in research and development activity.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Research and Development Arrangements - Additional Information (Detail) $ in Thousands, € in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2026 USD ($)	Jun. 30, 2026 EUR (€)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Jun. 30, 2026 EUR (€)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 28,624		$ 66,769	$ 47,979	$ 68,348
Accounts receivable	24,432			24,432		$ 17,764
Research and development	97,807		110,138	193,332	208,400
Corxel Aficamten License and Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum future development and commercial milestone payments achievable	160,000			160,000
Development and commercial milestone received						15,000	$ 10,000
Bayer License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable	2,500			2,500		2,600
Sanofi License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable	400			400		$ 15,100
Research Collaboration [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development	1,500		0	2,700	0
Research collaboration liability	2,500			2,500
License and Milestone Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	0		64,353	11,929	64,353
License and Milestone Revenues [Member] \| Bayer License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	11,900		64,300	11,900	64,300
Collaboration Revenues [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	3,290		2,416	5,927	3,995
Collaboration Revenues [Member] \| China [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	800		0	1,200	0
Collaboration Revenues [Member] \| Bayer License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues	$ 2,500		$ 2,400	$ 4,700	$ 3,900
Development and Commercial Milestones [Member] \| Bayer License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenues \| €		€ 10.0
Maximum milestone additional amount receivable \| €								€ 70.0
Commercial Milestone [Member] \| Bayer License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum milestone additional amount receivable \| €								€ 490.0