Fortress Biotech, Inc. Quarterly report pursuant to Section 13 or 15(d)

Sponsored Research and Clinical Trial Agreements (Narrative) (Details)

Sponsored Research and Clinical Trial Agreements (Narrative) (Details)		1 Months Ended					3 Months Ended		6 Months Ended
	Jul. 01, 2020 USD ($)	Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	May 31, 2020 USD ($)	Feb. 28, 2017 USD ($)	Mar. 31, 2015 USD ($) installment	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Nov. 30, 2020 USD ($)	Jul. 03, 2017 USD ($)
Research and development							$ 22,831,000	$ 15,703,000	$ 42,859,000	$ 30,570,000
Research and Clinical Trial Agreements [Member] \| Aevitas [Member]
Research and development							24,000		272,000	281,000
Research and Clinical Trial Agreements [Member] \| Aevitas [Member] \| University of Massachusetts [Member]
Research and development							24,000		272,000	0
Research and Clinical Trial Agreements [Member] \| Aevitas [Member] \| University of Pennsylvania [Member]
Research and development									0	281,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member]
Research and development							1,260,000	2,816,000	3,102,000	4,166,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member]
Research and development									0	500,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-102 (CD 123 CAR T for AML) [Member]
Research and development							21,000	65,000	226,000	296,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-104 (CS1 CAR T) [Member]
Research and development							197,000	770,000	372,000	770,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-101 (IL13R2 CAR T for Glioblastoma) [Member]
Research and development							279,000	234,000	793,000	326,000
Sponsored research agreement, funding commitment						$ 2,000,000.0
Number of installments to pay the upfront fees \| installment						4
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-103 (HER2 CAR T) [Member]
Research and development							31,000		154,000	0
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-105 (PSCA CAR T) [Member]
Research and development									46,000	0
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| Fred Hutchinson Cancer Research Center [Member] \| MB-106 (CD20 CAR T) [Member]
Research and development							327,000	189,000	998,000	716,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| St. Jude Children's Research Hospital [Member] \| MB-107 (XSCID) [Member]
Research and development							176,000	1,558,000	280,000	1,558,000
Research and Clinical Trial Agreements [Member] \| Mustang [Member] \| Mayo Clinic [Member]
Research and development							233,000		233,000	0
Research and Clinical Trial Agreements [Member] \| Oncogenuity [Member]
Research and development							348,000	125,000	671,000	125,000
Research and Clinical Trial Agreements [Member] \| Oncogenuity [Member] \| Columbia University [Member]
Research and development							187,000	125,000	375,000	125,000
Funding commitment period				5 years
Research and Clinical Trial Agreements [Member] \| Oncogenuity [Member] \| University of California [Member]
Research and development							66,000	0	122,000	0
Research and Clinical Trial Agreements [Member] \| Oncogenuity [Member] \| University of Oxford [Member]
Research and development							95,000	0	174,000	0
Research and Clinical Trial Agreements [Member] \| Oncogenuity [Member] \| Maximum [Member] \| Columbia University [Member]
Sponsored research agreement, funding commitment				$ 4,800,000
Sponsored Research Agreement [Member] \| Mustang [Member] \| City of Hope (COH) [Member]
Research and development									0	500,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-102 (CD 123 CAR T for AML) [Member]
Research and development							100,000	100,000	200,000	300,000
Upfront fees payment					$ 19,450
Sponsored research agreement, funding commitment					$ 200,000
Funding commitment period					3 years
Sponsored research agreement, additional funding commitment					$ 97,490
Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-104 (CS1 CAR T) [Member]
Research and development							200,000	800,000	400,000	800,000
Upfront fees payment										800,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-101 (IL13R2 CAR T for Glioblastoma) [Member]
Research and development							300,000	200,000	800,000	300,000
Upfront fees payment		$ 29,000			9,300
Payments of milestones					$ 100,000
Sponsored research agreement, funding commitment		100,000					200,000		200,000
Funding commitment period					3 years
Sponsored research agreement, additional funding commitment		200,000			$ 200,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-103 (HER2 CAR T) [Member]
Research and development							0.0		100,000
Upfront fees payment			$ 29,375
Clinical Trial Agreements [Member] \| Mustang [Member] \| City of Hope (COH) [Member] \| MB-105 (PSCA CAR T) [Member]
Research and development									100,000	0
Upfront fees payment		33,000
Sponsored research agreement, funding commitment		$ 2,300,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| Fred Hutchinson Cancer Research Center [Member] \| MB-106 (CD20 CAR T) [Member]
Research and development							300,000	200,000	1,000,000.0	700,000
Sponsored research agreement, funding commitment												$ 5,300,000
Sponsored research agreement, additional funding commitment											$ 800,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| St. Jude Children's Research Hospital [Member] \| MB-107 (XSCID) [Member]
Research and development							200,000	1,600,000	300,000	1,600,000
Upfront fees payment	$ 1,100,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| Mayo Clinic [Member]
Research and development							200,000		200,000
Sponsored research agreement, funding commitment							$ 2,100,000		$ 2,100,000
Funding commitment period									2 years
Clinical Trial Agreements [Member] \| Mustang [Member] \| Maximum [Member] \| City of Hope (COH) [Member] \| MB-104 (CS1 CAR T) [Member]
Sponsored research agreement, funding commitment								$ 2,400,000		$ 2,400,000
Clinical Trial Agreements [Member] \| Mustang [Member] \| Maximum [Member] \| City of Hope (COH) [Member] \| MB-103 (HER2 CAR T) [Member]
Sponsored research agreement, funding commitment			$ 3,000,000.0