Fortress Biotech, Inc. Annual report [Section 13 and 15(d), not S-K Item 405]

Intangible Assets, net (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2021	Jul. 31, 2020	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets				$ 3,424	$ 3,767
Payments of milestones				700	500
Asset Impairment Charges				$ 3,692	3,143
Journey
Finite-Lived Intangible Assets [Line Items]
Payments of milestones			$ 15,000
Asset Impairment Charges					$ 3,100
Achievement of Certain Sales Milestones \| Journey \| Dr. Reddy's Laboratories, Ltd
Finite-Lived Intangible Assets [Line Items]
Payments of milestones		$ 17,000
Qbrexza \| Dermira, Inc. a subsidiary of Eli Lilly
Finite-Lived Intangible Assets [Line Items]
Upfront fees payment	$ 12,500
Qbrexza \| Achievement of Certain Sales Milestones \| Journey \| Dermira, Inc. a subsidiary of Eli Lilly
Finite-Lived Intangible Assets [Line Items]
Payments of milestones		$ 144,000