Mustang Bio, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

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

License, Clinical Trial and Sponsored Research Agreements (City of Hope - Sponsored Research and Clinical Trial Agreements) (Narrative) (Details)			1 Months Ended						3 Months Ended		6 Months Ended
	Jul. 01, 2020 USD ($)	Jul. 03, 2017 USD ($)	Nov. 30, 2020 USD ($)	Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Feb. 28, 2017 USD ($)	Mar. 31, 2015 USD ($) installment	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development expense									$ 10,902,000	$ 9,830,000	$ 22,520,000	$ 19,144,000
Sponsored Research and Clinical Trial Agreements [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development expense									1,260,000	2,816,000	3,102,000	4,166,000
Sponsored Research and Clinical Trial Agreements [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable								$ 2,000,000.0
Number of installments \| installment								4
Research and development expense									0	0	0	500,000
Sponsored Research and Clinical Trial Agreements [Member] \| CD123 Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid							$ 19,450
Contribution toward patient costs							200,000
Contribution per patient							$ 97,490
Agreement term							3 years
Research and development expense									21,000	65,000	226,000	296,000
Sponsored Research and Clinical Trial Agreements [Member] \| IL13Ra2 Product [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid				$ 29,000			$ 9,300
Milestones payable							200,000
Additional milestone payments							$ 100,000
Contribution per patient				100,000
Agreement term							3 years
Research and development expense									279,000	234,000	793,000	326,000
Annual maintenance fee payable				200,000
Sponsored Research and Clinical Trial Agreements [Member] \| IL13Ra2 Product [Member] \| City of Hope National Medical Center ("COH") [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contribution toward patient costs											200,000
Sponsored Research and Clinical Trial Agreements [Member] \| CS1 Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable						$ 800,000
Research and development expense									197,000	770,000	372,000	770,000
Sponsored Research and Clinical Trial Agreements [Member] \| CS1 Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable						$ 2,400,000
Sponsored Research and Clinical Trial Agreements [Member] \| HER2 Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable					$ 29,375
Research and development expense									31,000	0	154,000	0
Sponsored Research and Clinical Trial Agreements [Member] \| HER2 Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable					$ 3,000,000.0
Sponsored Research and Clinical Trial Agreements [Member] \| PSCA Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable				33,000
Research and development expense									0	0	46,000	0
Sponsored Research and Clinical Trial Agreements [Member] \| PSCA Product or Process [Member] \| City of Hope National Medical Center ("COH") [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable				$ 2,300,000
Sponsored Research and Clinical Trial Agreements [Member] \| CD20 Product or Process [Member] \| Fred Hutchinson Cancer Research Center [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestones payable		$ 5,300,000
Additional milestone payments			$ 800,000
Research and development expense									327,000	189,000	998,000	716,000
Sponsored Research and Clinical Trial Agreements [Member] \| ST. Jude - XSCID [Member] \| St. Jude Children's Research Hospital [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fees paid	$ 1,100,000
Research and development expense									$ 176,000	$ 1,558,000	$ 280,000	$ 1,558,000