Mustang Bio, Inc. Annual report pursuant to Section 13 and 15(d)

License, Clinical Trial and Sponsored Research Agreements (City of Hope - Licenses) (Narrative) (Details)

License, Clinical Trial and Sponsored Research Agreements (City of Hope - Licenses) (Narrative) (Details) € in Millions					1 Months Ended				12 Months Ended
	Sep. 08, 2021 USD ($)	Apr. 01, 2021 USD ($) Milestone	Aug. 23, 2019 USD ($) item	Jul. 03, 2017 USD ($)	Oct. 31, 2020 USD ($) item	Oct. 31, 2020 EUR (€) item	May 31, 2017 USD ($) item	Feb. 28, 2017 USD ($) item	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development - licenses acquired									$ 5,842,000	$ 10,064,000
Mayo Clinic [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid		$ 800,000
License Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development - licenses acquired									5,842,000	10,064,000
License Agreements [Member] \| CSL Behring (Calimmune) [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid			$ 200,000
Number of milestones \| item			3
Milestones payable			$ 1,200,000
Research and development - licenses acquired									30,000	170,000
License Agreements [Member] \| Leiden University Medical Centre [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid	$ 400,000
Milestones payable	$ 31,000,000
Research and development - licenses acquired									350,000	0
License Agreements [Member] \| Mayo Clinic [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable		$ 25,000
Number of milestones \| Milestone		11
Milestones payable		$ 92,600,000
Research and development - licenses acquired									750,000	0
License Agreements [Member] \| SIRION Biotech [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid					$ 100,000	€ 0.1
Research and development - licenses acquired									0	117,000
License Agreements [Member] \| SIRION Biotech [Member] \| Achievement of Certain Development Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of milestones \| item					5	5
Milestones payable					$ 5,200,000	€ 4.7
License Agreements [Member] \| SIRION Biotech [Member] \| Achievement of Certain Commercial Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of milestones \| item					3	3
Additional milestone payments					$ 3,900,000	€ 3.5
License Agreements [Member] \| CD123 (MB-102) [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable								$ 25,000
Milestones payable								$ 14,500,000
Research and development - licenses acquired									250,000	334,000
License Agreements [Member] \| CS1 (MB-104) [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable							$ 50,000
Upfront fees paid							$ 600,000
Number of milestones \| item							10
Milestones payable							$ 14,900,000
Research and development - licenses acquired									0	200,000
License Agreements [Member] \| IL13Ra2 (MB-101) [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of milestones \| item								8
Milestones payable								$ 14,500,000
Research and development - licenses acquired									0	333,000
License Agreements [Member] \| Spacer [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development - licenses acquired									0	333,000
License Agreements [Member] \| PSCA (MB-105) [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable							50,000
Upfront fees paid							$ 300,000
Number of milestones \| item							10
Milestones payable							$ 14,900,000
Research and development - licenses acquired									250,000	200,000
License Agreements [Member] \| HER2 (MB 103) [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable							50,000
Upfront fees paid							$ 600,000
Number of milestones \| item							10
Milestones payable							$ 14,900,000
Research and development - licenses acquired									0	500,000
License Agreements [Member] \| CD20 (MB-106) [Member] \| Fred Hutchinson Cancer Research Center [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee payable				$ 50,000
Upfront fees paid				300,000
Additional milestone payments				$ 39,100,000
Research and development - licenses acquired									$ 0	$ 300,000