Fortress Biotech, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Licenses Acquired - license as recorded in the Condensed Consolidated Statements of Operations (Detail)

Licenses Acquired - license as recorded in the Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	$ 4,050	$ 4,164
Mustang Therapeutics, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	1,275	2,875
Mustang Therapeutics, Inc [Member] \| Manufacturing [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	75	0
Mustang Therapeutics, Inc [Member] \| IL13Rα2 [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	500
Mustang Therapeutics, Inc [Member] \| IVICV [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	125
Mustang Therapeutics, Inc [Member] \| PSCA [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	300
Mustang Therapeutics, Inc [Member] \| HER2 [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	200	600
Mustang Therapeutics, Inc [Member] \| CSI [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	600
Mustang Therapeutics, Inc [Member] \| Harvard CRISPR [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	250
Mustang Therapeutics, Inc [Member] \| UCLA [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	200
Mustang Therapeutics, Inc [Member] \| Fred Hutch Cd 20 [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	0	300
Mustang Therapeutics, Inc [Member] \| St Jude XSCID [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process	$ 1,000	$ 0