Collaboration and license agreements - Narrative (Details) $ / shares in Units, $ in Thousands					1 Months Ended									3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) performanceObligation shares	Mar. 01, 2024 USD ($) target performanceObligation	Dec. 11, 2023 USD ($) performanceObligation	May 29, 2023 USD ($) $ / shares shares	Sep. 30, 2025 USD ($) performanceObligation shares	Apr. 30, 2025 USD ($)	Sep. 30, 2024 USD ($) developmentCandidate	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) target	Nov. 30, 2020 USD ($) target	Feb. 29, 2020 USD ($) protein	Dec. 31, 2018 USD ($) target performanceObligation	Sep. 30, 2025 USD ($) performanceObligation shares	Sep. 30, 2024 USD ($) developmentCandidate	Sep. 30, 2025 USD ($) performanceObligation shares	Sep. 30, 2024 USD ($) developmentCandidate	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of performance obligations | performanceObligation													12
Transaction price allocated to performance obligation	$ 23,064				$ 23,064									$ 23,064		$ 23,064
Contract with customer, liability	$ 37,014				$ 37,014									37,014		37,014			$ 47,169
Revenue recognized that was included in the contract liability at the beginning of the period														$ 6,581	$ 4,994	$ 13,822	$ 9,996
Discovery, Regulatory, and Commercial Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive		$ 740,000
Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement				90 days
MKDG Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of potential research and development targets | target		2
Upfront payment		$ 16,000
Regulatory milestone achieved						$ 1,000
Addition to the transaction price						$ 1,000
Number of performance obligations | performanceObligation	2	2			2									2		2
Transaction price allocated to performance obligation	$ 17,000				$ 17,000									$ 17,000		$ 17,000
Contract with customer, liability	10,562				10,562									10,562		10,562			13,373
MKDG Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement		60 days
Betta Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	10,000			$ 10,000
Regulatory milestone achieved										$ 2,000
Contract with customer, liability	$ 14,889				$ 14,889									$ 14,889		$ 14,889			15,281
Stock repurchase program, number of shares authorized to be repurchased (in shares) | shares				5,567,928
Stock repurchase program, authorized amount				$ 25,000
Share price (in dollars per share) | $ / shares				$ 4.49
Stock repurchase program, premium percentage				25.00%
Duration of trading day volume weighted average closing price				60 days
Trading days prior to the effective date of the Stock Purchase Agreement				2 days
Stock ownership of Company by third party (in shares) | shares	4,874,550				4,874,550									4,874,550		4,874,550
Estimated transaction price	$ 125,000				$ 125,000									$ 125,000		$ 125,000
Transaction price from closing of the stock purchase agreement	5,000
Expected consideration to be received from manufactured clinical supply	108,000				108,000									108,000		108,000
Betta Agreements | Research and development milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive				$ 357,000
Betta Agreements | Drug Application Approval
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive				$ 40,000
Restated Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone achieved									$ 2,000
Addition to the transaction price																		$ 4,000
Additional upfront consideration received													$ 40,000
Number of potential targets | target											5		6
Number of targets | target										2	2
Annual research plan payments receivables											$ 1,000
Option exercise fees											$ 8,000
Restated Roche Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement											90 days
Restated Roche Agreement | Maximum | Research, development and commercial milestone payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive											$ 273,000
Restated Roche Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive											150,000
Restated Roche Agreement | Lead series identification achievement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees											$ 2,000
Biogen Research and License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone achieved					2,000
Research agreement, period												54 months
Nonrefundable upfront payment												$ 45,000
Revenue recognized that was included in the contract liability at the beginning of the period							$ 8,000	$ 8,000
Number of development candidates | developmentCandidate							2								2		2
Biogen Research and License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targeted protein degradation | protein												5
Biogen Research and License Agreement | Maximum | Research and development milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received												$ 35,000
Biogen Research and License Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received												$ 26,000
Merck Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment			$ 10,000
Number of performance obligations | performanceObligation			1
Contract with customer, liability	0				0									0		0			$ 6,022
Estimated transaction price	10,000				10,000									10,000		10,000
Merck Agreement | Research and development milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			$ 600,000
Restated Roche Agreement And Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligation	$ 154,200				$ 154,200									$ 154,200		$ 154,200