Leases - Additional Information (Details) $ in Thousands	1 Months Ended						12 Months Ended
	Sep. 30, 2023 USD ($)	Feb. 28, 2022	Jan. 31, 2021 RenewalOption	Nov. 30, 2020	Jul. 31, 2019	Jul. 31, 2016 RenewalOption	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Oct. 31, 2023 USD ($)
Lessee Lease Description [Line Items]
Operating lease right-of-use assets							$ 30,997	$ 21,288
Operating lease liabilities							29,224	17,941
Operating leases rent expense recognized							8,500	$ 7,900	$ 3,200
Assignment Agreement
Lessee Lease Description [Line Items]
Operating lease, agreement term	10 years
Operating lease, commencement date	Oct. 01, 2023
Assumed lease rental payment	$ 1,900
Operating lease rental adjustment	3.00%
Lease expiration date	Nov. 30, 2031
Operating lease right-of-use assets										$ 16,700
Operating lease liabilities										$ 16,800
Lonza Commercial Manufacturing And Supply Agreement [Member]
Lessee Lease Description [Line Items]
Operating lease liabilities							$ 0
Lessee, Operating Lease, Lease Not yet Commenced, Description							As of December 31, 2023, the lease had not commenced and, as such, no lease liability or ROU asset was recorded on the consolidated balance sheets and no operating lease expense was recorded on the consolidated statements of operations.
Operating leases rent expense recognized							$ 0
Headquarters Facility
Lessee Lease Description [Line Items]
Operating lease, agreement term						5 years
Operating lease, commencement date						Sep. 01, 2016
Lease termination date		Feb. 12, 2022
Lease expiration date						Aug. 31, 2021
Operating lease, renewal option | RenewalOption						2
Operating lease, renewal term						30 months
Operating lease, option to renewal, description							30-month renewal options
Operating lease, existence of option to renewal						true
Operating lease, description							In July 2016, we entered into a five-year lease agreement for our previous headquarters facility located in Foster City, California. The original term of the lease was from September 1, 2016 to August 31, 2021, with two 30-month renewal options.
Operating lease, extended term				6 months
Operating lease, extended maturity date				Mar. 01, 2022
Additional Facility
Lessee Lease Description [Line Items]
Operating lease, commencement date					Jul. 01, 2019
Lease expiration date					Oct. 31, 2021
Operating lease, option to renewal, description							no renewal options
Operating lease, existence of option to renewal					false
Operating lease, description							In July 2019, we leased another facility in Foster City, California. The original term of this lease was from July 1, 2019 to October 31, 2021, with no renewal options.
Operating lease, extended term				6 months
Operating lease, extended maturity date				Apr. 30, 2022
New Corporate Headquarters Facility
Lessee Lease Description [Line Items]
Operating lease, commencement date			Dec. 03, 2021
Lease expiration date			Dec. 31, 2025
Operating lease, renewal term			60 months
Operating lease, extended term			60 days
Number of renewal options | RenewalOption			2
Palo Alto
Lessee Lease Description [Line Items]
Operating lease, extended maturity date			Mar. 03, 2022
San Carlos
Lessee Lease Description [Line Items]
Operating lease right-of-use assets							$ 28,400
Operating lease liabilities							$ 12,900