Commitments and Contingencies - Additional Information (Detail) - USD ($)				3 Months Ended	12 Months Ended
	May 28, 2019	Aug. 17, 2015	Jan. 13, 2015	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Oct. 22, 2019	Feb. 19, 2019	Oct. 05, 2018	Aug. 24, 2004
Accrued Payments
Royalty amount					$ 0	$ 0
Research and development expense					25,018,000	49,643,000
Collaboration revenue					2,922,000	398,000
Md Anderson Warrant [Member]
Accrued Payments
Number of Warrants							3,333,333
Warrant exercise per share							$ 0.001
Warrant Expiry date							Dec. 31, 2026
MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Reimbursement of historical costs							$ 20,000,000.0
Payments due prior to the first marketing approval							3,000,000.0
Quarterly expense incurred					800,000	300,000
Aggregate potential benchmark payments							$ 36,500,000
CRADA Agreement [Member]
Accrued Payments
Contribution payable on per annum basis				$ 1,000,000.0
Obligations due under contract								$ 5,000,000.0
Annual expense incurred					0	1,300,000
Quarterly payments under contract					3,800,000
MD Anderson Agreement and Worldwide License [Member]
Accrued Payments
License agreement commencing date			Jan. 13, 2015
C A R Products [Member]
Accrued Payments
Maximum royalty amount									$ 100,000,000.0
The University of Texas MD Anderson Cancer Center and The Texas A & M University System [Member]
Accrued Payments
Milestone maximum payment										$ 4,500,000
One time milestone payment					2,500,000
Payment under license agreement						100,000
The University of Texas MD Anderson Cancer Center and The Texas A & M University System [Member] | Royalty [Member]
Accrued Payments
Payment under license agreement					2,000	0
Collaboration Agreement with Solasia Pharma K.K. [Member]
Accrued Payments
Collaboration revenue					2,900,000	400,000
License Agreement with the National Cancer Institute [Member]
Accrued Payments
License Expense					700,000	$ 500,000
License Agreement with the National Cancer Institute [Member] | One Time Benchmark Payments [Member]
Accrued Payments
First benchmark payment					$ 100,000
Ziop License Agreement With The National Cancer Institute [Member]
Accrued Payments
Minimum royalties amount payable	$ 300,000
Aggregate minimum annual royalties paid	1,500,000
Royalties amount payable thereafter	$ 100,000
Description Of First Benchmark Payable	The first benchmark payment of $0.1 million was paid during the year ended December 31, 2022 upon the initiation of the Company's TCR-T Library Phase 1/2 Trial, which was a qualifying Phase 1 clinical trial under the terms of the Patent License.
Description Of option To terminate Agreement	The NCI may terminate or modify the Patent License in the event of a material breach, including if the Company does not meet certain milestones by certain dates, or upon certain insolvency events that remain uncured following the date that is 90 days following written notice of such breach or insolvency event.
Agreement termination, notice period	60 days
Ziop License Agreement With The National Cancer Institute [Member] | Performance Based Payments [Member]
Accrued Payments
Aggregate Benchmark Payments Payable	$ 4,300,000
Ziop License Agreement With The National Cancer Institute [Member] | One Time Benchmark Payments [Member]
Accrued Payments
Potential Benchmark Payments Payable	12,000,000.0
Ziop License Agreement With The National Cancer Institute [Member] | Post Marketing Approval [Member] | Performance Based Payments [Member]
Accrued Payments
Aggregate Benchmark Payments Payable	3,000,000.0
Ziop License Agreement With The National Cancer Institute [Member] | Licensed Products [Member] | One Time Benchmark Payments [Member]
Accrued Payments
Maximum Sales Revenue On Which Benchmark Payments Payable	1,000,000,000.0
Minimum sales revenue on which benchmark payments payable	$ 250,000,000.0
Intrexon Corporation [Member]
Accrued Payments
Annual License fee									100,000
Expected additional milestones payable									52,500,000
Intrexon Corporation [Member] | T-Cell Receptor [Member]
Accrued Payments
Maximum royalty amount									$ 100,000,000.0
Portion of income payable to related party									20.00%
Minimum [Member] | MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Research and development expense		$ 15,000,000.0
Maximum [Member] | MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Research and development expense		$ 20,000,000.0