Subsequent events (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Feb. 02, 2024	Jan. 04, 2024	Dec. 31, 2023	Mar. 31, 2024	Feb. 29, 2024	Dec. 28, 2023	Dec. 31, 2022
Subsequent events
Par value of common stock (in dollars per share)			$ 0.001				$ 0.001
Purchase of common stock			$ 31,121
2023 Novartis Collaboration Agreement | Novartis
Subsequent events
Shares of common stock						2,145,002
Number of shares agreed to be issued, price per share						$ 9.324
Aggregate purchase price						$ 20,000
Subsequent events
Subsequent events
Offering price for common stock		$ 9.00
Subsequent events | Neurocrine
Subsequent events
Milestone payment to be received				$ 5,000	$ 5,000
Subsequent events | Pre-Funded Warrants
Subsequent events
Offering price for warrants		$ 8.999
Subsequent events | Underwriting Agreement
Subsequent events
Issuance of common stock in connection with the 2023 Neurocrine Collaboration Agreement (in shares)		7,777,778
Par value of common stock (in dollars per share)		$ 0.001
Offering price for common stock		$ 8.46
Period for option to exercise additional number of shares	30 days	30 days
Additional number of shares to be issued		1,666,665
Net proceeds received		$ 93,500
Subsequent events | Underwriting Agreement | Pre-Funded Warrants
Subsequent events
Offering price for warrants		$ 8.459
Subsequent events | Underwriting Agreement | Pre-Funded Warrants | Maximum
Subsequent events
Number of warrants issued to purchase common stock		3,333,333