Leases - Additional Information (Detail) $ in Millions		1 Months Ended	12 Months Ended
	Feb. 15, 2018 USD ($) ft²	Mar. 31, 2021 USD ($) ft²	Dec. 31, 2021 USD ($)
South San Francisco California
Lessee Lease Description [Line Items]
Lease expiration date			May 31, 2025
South San Francisco California | Line of Credit
Lessee Lease Description [Line Items]
Letter of credit maintained			$ 0.1
Letter of credit renewal term			12 months
Letter of credit, decrease from prior lease agreement			$ 0.1
Restricted cash related to letter of credit			$ 0.2
Thousand Oaks California
Lessee Lease Description [Line Items]
Lease agreement area of square feet of office, lab and warehouse space | ft²		33,659
Lease initial term	15 years	10 years 6 months
Contractual obligations	$ 16.4	$ 21.0
Percentage of annual increase in base rent		3.00%
Operating lease, option to extend		0
Lease option to extend additional term		5 years
Lease agreement area of office, lab and cellular therapy manufacturing space | ft²	90,580
Lease commencement date	Feb. 15, 2018
Lease extension term, option one	10 years
Lease extension term, option two	9 years
Thousand Oaks California | Additional Office Space
Lessee Lease Description [Line Items]
Lease expiration date			Feb. 28, 2026
Operating lease, option to extend			we have the option to extend the lease for an additional period of five years after the initial term.
Lease option to extend additional term			5 years
Operating lease, existence of option to extend [true false]			true
Thousand Oaks California | Line of Credit
Lessee Lease Description [Line Items]
Letter of credit issued, classified as long-term restricted cash	$ 1.2
Aurora Colorado
Lessee Lease Description [Line Items]
Lease expiration date			Apr. 30, 2024
Incremental contractual obligations under lease amendment			$ 0.2