Leases - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended					3 Months Ended		9 Months Ended
	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	May 31, 2020	May 31, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee Lease Description [Line Items]
Rent expense						$ 0.7	$ 0.5	$ 1.9	$ 1.4
Cash paid for operating leases						$ 0.6	$ 0.4	$ 1.6	$ 1.3
Weighted-average discount rate						9.10%		9.10%
Expects to pay base rent over the lease term		$ 98.8
Lessee, operating lease, term of contract		12 years
Monthly base rent		$ 0.6
Maximum monthly base rent after increase on annual basis		0.8
Cash received for tenant improvement allowances to be repaid		4.4
Maximum
Lessee Lease Description [Line Items]
Tenant improvement allowances yet to receive		$ 25.2
Letter of Credit
Lessee Lease Description [Line Items]
Security deposit						$ 1.6		$ 1.6
Third amendment
Lessee Lease Description [Line Items]
Lessee option to extend description								The lease amendment for this additional space commenced in April 2021 and expires in March 2024
Lease expiration month and year			2024-03
Initial Lease Agreement
Lessee Lease Description [Line Items]
Lease expiration year				2029
Operating lease, existence of option to extend				true
Lessee option to extend description								The lease amendment also includes an extension of the lease term for the existing office and laboratory space beginning on May 1, 2020 and expiring in January 2029. The amendment to the Initial Lease Agreement also includes an option to extend the lease for an additional seven-year term
Lease term				8 years
Initial Lease Agreement | Subsequent Event
Lessee Lease Description [Line Items]
Lease expiration year	2029
Operating lease, existence of option to extend	true
Lessee option to extend description	The lease amendment of this additional space is anticipated to commence in April 2022 and expires in January 2029. The Company expects to pay base rent of approximately $4.6 million over the lease term. The lease amendment also includes this additional space in the Company’s option to extend the amended Initial Lease Agreement for an additional seven-year term.
Expects to pay base rent over the lease term	$ 4.6
Current Corporate Offices and Laboratory Space
Lessee Lease Description [Line Items]
Weighted-average remaining lease term						6 years 10 months 24 days		6 years 10 months 24 days
Corporate Office and Laboratory Space | Initial Lease Agreement
Lessee Lease Description [Line Items]
Lease expiration year					2025
Operating lease, existence of option to extend					true
Lessee option to extend description								In April 2019, the Company executed the first amendment to the Initial Lease Agreement for additional corporate space, laboratory space and manufacturing capabilities and an extension to the lease term through April 2026.
Renewal term				7 years