Commitments and Contingencies - Additional Information (Details) - USD ($)				1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	May 28, 2019	Aug. 17, 2015	Jan. 13, 2015	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2019	Oct. 22, 2019	Feb. 19, 2019	Oct. 05, 2018	Aug. 24, 2004
Accrued Payments
Research and development expense					$ 5,937,000	$ 13,570,000	$ 11,518,000	$ 26,906,000
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 Agreement and Worldwide License [Member]
Accrued Payments
Agreement commencement date			2015-05
MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Reimbursement of historical costs										$ 20,000,000.0
Quarterly payments under contract					600,000	0	1,000,000.0	0
Aggregate potential benchmark payments										36,500,000
Payments due prior to the first marketing approval										$ 3,000,000.0
CRADA Agreement [Member]
Accrued Payments
Quarterly payments under contract					0	600,000	0	1,300,000
Contribution payable on quarterly basis				$ 1,000,000.0
Obligations due under contract											$ 5,000,000.0
CAR 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
Accrued Payments
Milestone maximum payment													$ 4,500,000
Payment under license agreement					0			0
License Agreement with the National Cancer Institute [Member]
Accrued Payments
License Expense					200,000	100,000	500,000	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
Royalties amount payable thereafter	100,000
Aggregate minimum annual royalties paid	$ 1,500,000
Description Of First Benchmark Payable	The first benchmark payment of $0.1 million will be due upon the initiation of the Company's first sponsored Phase 1 clinical trial of a licensed product or licensed process in the field of use licensed under the Patent License. The Company paid the first benchmark payment during the three months ended June 30, 2022.
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 [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 [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
Collaboration Agreement With Solasia Pharma KK [Member]
Accrued Payments
Collaboration revenue					$ 0	$ 0	$ 0	$ 0
Intrexon Corporation
Accrued Payments
Annual License Fees												100,000
Expected additional milestones payable												52,500,000
Payment for historical costs of the licensed programs									$ 1,000,000.0
Intrexon Corporation | T-cell receptor
Accrued Payments
Maximum royalty amount												$ 100,000,000.0
Portion of income payable to related party												20.00%
Minimum | MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Research and development expense		$ 15,000,000.0
Maximum | MD Anderson License and the Research and Development Agreement [Member]
Accrued Payments
Research and development expense		$ 20,000,000.0