Commitment and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Nov. 30, 2021 USD ($) ft²	Apr. 30, 2020 USD ($) ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Oct. 31, 2018 ft²	Jan. 31, 2015 ft²
Lessee Lease Description [Line Items]
Operating lease right-of-use asset			$ 56,259		$ 56,259		$ 59,692
Operating lease liability			65,200		65,200		$ 66,633
Operating lease cost			1,800	$ 900	4,700	$ 2,100
Sublease income			500	400	1,200	1,500
Operating cash flows for operating leases			$ 200		$ 1,400
Operating cash flows for operating leases				$ 700		$ 900
Operating lease, weighted average discount rate			6.10%		6.10%
Operating lease, weighted average remaining lease term			11 years		11 years		11 years 7 months 6 days
Redwood City Lease
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year					2033-11
Area of space leased | ft²	41,000
Lessee, operating lease option to extend lease term	10 years
Redwood City Lease | ASC 842
Lessee Lease Description [Line Items]
Operating lease right-of-use asset	$ 26,800
Redwood City Lease | Restricted Cash
Lessee Lease Description [Line Items]
Letter of credit			$ 1,700		$ 1,700		$ 1,700
Redwood City Lease | The 700 Building and 300 Building | ASC 842
Lessee Lease Description [Line Items]
Increase in operating lease right-of-use asset	$ 8,600
Redwood City Lease | The 300 Building
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year					2030-12
Area of space leased | ft²		19,000
Tenant improvement allowance					$ 4,600
Redwood City Lease | The 300 Building | ASC 842
Lessee Lease Description [Line Items]
Operating lease right-of-use asset		$ 6,400
Operating lease liability		9,000
Redwood City Lease | The 700 Building
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year					2023-04
Area of space leased | ft²									42,000
Tenant improvement allowance					$ 3,400
Redwood City Lease | The 700 Building | ASC 842
Lessee Lease Description [Line Items]
Increase in operating lease right-of-use asset		$ 14,800
Redwood City Lease | The 800 Building
Lessee Lease Description [Line Items]
Lessee, operating lease, option to extend					The Company has the option to extend the lease for an additional ten years after November 30, 2033.
Cambridge, Massachusetts
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year					2023-02
Area of space leased | ft²								22,000
Lessee, operating lease, option to extend					option to extend the term through February 2028
Cambridge, Massachusetts | Restricted Cash
Lessee Lease Description [Line Items]
Letter of credit			$ 200		$ 200		$ 200