Operating Leases - Additional Information (Details) $ in Thousands			1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	May 10, 2021 USD ($)	Jan. 27, 2021 OfficeSuite	Mar. 31, 2021	Apr. 30, 2020	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Lessee Lease Description [Line Items]
Term of contract				1 year
Operating lease commencement date				May 11, 2020
Operating lease maturity date			Sep. 30, 2021	Jun. 30, 2021
Lessee, operating lease, option to extend						The original term of the lease was from May 11, 2020 to June 30, 2021 with an option to renew. In March 2021, the Company entered into an amendment to the lease agreement and extended the term of the lease to September 30, 2021.
Lessee, Operating Lease, Existence of Option to Extend [true false]				true
Operating lease base rent						$ 0	$ 200
Operating lease right-of-use assets					$ 9,077	9,077
Operating lease, liability					9,490	9,490
Current portions of operating lease liability					4,806	4,806
Non-current portions of operating lease liability					$ 4,684	$ 4,684
Remaining lease term on operating lease					30 months	30 months
Weighted average incremental borrowing rate on operating lease					8.50%	8.50%
Lease expense					$ 600	$ 800
Variable lease payments					100	$ 200
New Lease Agreement
Lessee Lease Description [Line Items]
Lessee, operating lease, option to extend						The term of the lease is 44 months for the first office suite and 43 months for the second office suite with an option to extend the term for an additional two years on the same terms and conditions.
Lessee, Operating Lease, Existence of Option to Extend [true false]		true
Number of office suites | OfficeSuite		2
Lessee, operating lease, renewal term		2 years
Operating lease right-of-use assets					4,000	$ 4,000
Operating lease, liability					$ 4,100	$ 4,100
First Office Suite
Lessee Lease Description [Line Items]
Term of contract		44 months
Operating lease commencement date		Jul. 31, 2021
Second Office Suite
Lessee Lease Description [Line Items]
Term of contract		43 months
Operating lease commencement date		Aug. 31, 2021
Embedded Lease Agreement | Laboratory For Cell And Gene Medicine
Lessee Lease Description [Line Items]
Finance lease maturity date	Apr. 30, 2023
Fixed lease payments	$ 5,600