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

License Acquired (Journey and Other Narrative) (Details)

License Acquired (Journey and Other Narrative) (Details) $ in Thousands, ¥ in Billions				1 Months Ended					12 Months Ended		24 Months Ended
	Oct. 01, 2023 JPY (¥)	Aug. 31, 2023 USD ($)	Jul. 31, 2020 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	May 31, 2021 USD ($)	Jul. 31, 2020 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments of milestones											$ 500
Other revenue									$ 19,519	$ 2,674
Journey \| Dr. Reddy's Laboratories, Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees payment								$ 1,000
Payments of milestones								$ 4,000
Journey \| Dr. Reddy's Laboratories, Ltd \| Achievement of Certain Sales Milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments of milestones			$ 17,000
Journey \| Maruho Co Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees payment		$ 19,000
Payments of milestones		$ 45,000
Other revenue									$ 19,000
Net Sales \| ¥	¥ 4
Journey \| Licensing Agreements \| Dr. Reddy's Laboratories, Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments for research and development expenses						$ 23,800
Journey \| Licensing Agreements \| Dr. Reddy's Laboratories, Ltd \| DFD Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees payment						10,000
Journey \| Licensing Agreements \| Dr. Reddy's Laboratories, Ltd \| Achievement of Certain Clinical Development, Regulatory and First Commercial Sale milestones \| DFD Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments of milestones						$ 158,000
Journey \| Licensing Agreements \| Minimum \| Dr. Reddy's Laboratories, Ltd \| Payable on Net Sales of the DFD-29 Product \| DFD Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Sales royalties (as a percent)						10.00%
Journey \| Licensing Agreements \| Maximum \| Dr. Reddy's Laboratories, Ltd \| Payable on Net Sales of the DFD-29 Product \| DFD Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Sales royalties (as a percent)						15.00%
Urica \| Licensing Agreements \| Fuji Yakuhin Co. Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments of milestones					$ 3,000
One-time amendment payment				$ 300
Urica \| Licensing Agreements \| Minimum \| Fuji Yakuhin Co. Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Sales royalties (as a percent)							7.00%
Urica \| Licensing Agreements \| Maximum \| Fuji Yakuhin Co. Ltd
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments of milestones							$ 88,000
Sales royalties (as a percent)							10.00%