Collaboration and license agreements - Schedule of revenue from collaboration agreements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	$ 11,230	$ 15,362	$ 24,931	$ 30,407
MKDG Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	3,360	2,368	9,941	4,317
Merck Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	3,842	1,684	6,020	3,431
Betta Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	27	2,896	541	2,896
Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	2,001	414	6,429	2,865
Biogen Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	$ 2,000	$ 8,000	$ 2,000	$ 16,898

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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+ Details

C4 Therapeutics, Inc. 10-Q