Commitments and Contingencies - Additional Information (Details) - USD ($)						3 Months Ended
	Oct. 20, 2023	Aug. 14, 2023	Mar. 17, 2023	Aug. 17, 2015	Jan. 13, 2015	Mar. 31, 2024	Mar. 31, 2023	Apr. 03, 2023	Oct. 22, 2019	Oct. 05, 2018	Aug. 24, 2004
Accrued Payments
Research and development expense						$ 126,000	$ 6,504,000
Royalty amount							0
Maximum royalty amount										$ 100,000,000
Collaboration revenue						1,000	0
Unspecified monetary damages			$ 3,200,000
Loss contingency, name of plaintiff			KBI Biopharma
Litigation expense	$ 1,000,000
MD Anderson Warrant [Member]
Accrued Payments
Number of warrants									222,222
Warrant exercise per share									$ 0.015
Warrant expiry date									Dec. 31, 2026
MD Anderson Agreement and Worldwide License [Member]
Accrued Payments
License agreement commencing date					Jan. 13, 2015
MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Reimbursement of historical costs									$ 20,000,000
Quarterly expense incurred						0	200,000
Aggregate potential benchmark payments									36,500,000
Payments due prior to the first marketing approval									$ 3,000,000
CRADA Agreement [Member]
Accrued Payments
Agreement termination date		Oct. 13, 2023
Annual expense incurred						0	300,000
The University of Texas MD Anderson Cancer Center and The Texas A & M University System [Member]
Accrued Payments
Milestone maximum payment											$ 4,500,000
The University of Texas MD Anderson Cancer Center and The Texas A & M University System [Member] | Royalty [Member]
Accrued Payments
Payment under license agreement						0	0
License Agreement with the National Cancer Institute [Member]
Accrued Payments
License expense						0	300,000
Collaboration Agreement with Solasia Pharma KK [Member]
Accrued Payments
Collaboration revenue						0	0
Collaboration Agreement with Solasia Pharma KK [Member] | Royalty [Member]
Accrued Payments
Collaboration revenue						1,000	0
M D Anderson License and the Two Thousand Fifteen Research and Development Agreement [Member]
Accrued Payments
Clinical expenses						$ 0	$ 0
Intrexon Corporation [Member]
Accrued Payments
Annual license fee								$ 75,000		100,000
Expected additional milestones payable										52,500,000
Intrexon Corporation [Member] | T-cell receptor [Member]
Accrued Payments
Maximum royalty amount										$ 100,000,000
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
Maximum [Member] | MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Research and development expense				$ 20,000,000