Collaboration and license agreements - Narrative (Details) $ / shares in Units, $ in Thousands					1 Months Ended								3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($) target performanceObligation	Mar. 01, 2024 USD ($) target	Dec. 11, 2023 USD ($) target performanceObligation	May 29, 2023 USD ($) $ / shares 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	Jun. 30, 2025 USD ($) target performanceObligation	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) target performanceObligation	Jun. 30, 2024 USD ($)	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
Contract with customer, liability	43,770												43,770		43,770			$ 47,169
Revenue from collaboration agreements													6,463	$ 12,006	13,701	$ 15,045
Revenue recognized that was included in the contract liability at the beginning of the period													6,512	2,065	11,821	5,003
Discovery, Regulatory, and Commercial Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive	$ 740,000												$ 740,000		$ 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	2											2		2
Upfront payment		$ 16,000
Regulatory milestone achieved					$ 1,000
Addition to the transaction price	$ 1,000												$ 1,000		$ 1,000
Number of performance obligations | performanceObligation	2												2		2
Transaction price allocated to performance obligation	$ 17,000												$ 17,000		$ 17,000
Contract with customer, liability	11,892												11,892		11,892			13,373
Revenue from collaboration agreements													3,428	1,894	6,581	1,949
MKDG Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement		60 days
Merck Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment			$ 10,000
Number of performance obligations | performanceObligation			1
Contract with customer, liability	3,843												3,843		3,843			6,022
Option to include number of additional targets | target			3
Potential proceeds from collaboration			$ 2,500,000
Estimated transaction price	10,000												10,000		10,000
Revenue from collaboration agreements													1,049	1,102	2,178	1,747
Merck Agreement | Research and development milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			$ 600,000
Merck 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	14,970												14,970		14,970			$ 15,281
Estimated transaction price	135,000												135,000		135,000
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
Transaction price from closing of the stock purchase agreement	5,000
Expected consideration to be received from manufactured clinical supply	118,000												118,000		118,000
Revenue from collaboration agreements													54	$ 0	514	$ 0
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
Number of targets | target									2	2
Additional upfront consideration received												$ 40,000
Number of potential targets | target										5		6
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]
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
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
Restated Roche Agreement And Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligation	$ 161,400												$ 161,400		$ 161,400