Leases - Narrative (Details) $ in Thousands	Sep. 28, 2023 USD ($) ft²	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	[1]
Lessee, Lease, Description [Line Items]
Future lease payments		$ 42,669
Operating lease right-of-use assets		28,054		$ 1,211
California
Lessee, Lease, Description [Line Items]
Leased premises under non cancelable operating lease | ft²	100,904,000
Lease term	7 years
Lease term extension period	8 years
Future lease payments		$ 43,400
Operating lease, liability			$ 29,800
Operating lease right-of-use assets			$ 29,800
California | Landlord | Letter of Credit | Pliant Therapeutics
Lessee, Lease, Description [Line Items]
Line of credit	$ 1,400

[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date.