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

Revenues from Contracts and Significant Customers (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) customer	Dec. 31, 2024 USD ($) customer
Revenues from Contracts and Significant Customers
Other revenue	$ 2,023	$ 1,000
Dermatology Products Sales \| Customer Concentration Risk \| Revenue
Revenues from Contracts and Significant Customers
Number of customers \| customer	0	0
Dermatology Products Sales \| Customer Concentration Risk \| Accounts Receivable
Revenues from Contracts and Significant Customers
Number of customers \| customer	0	1
Dermatology Products Sales \| Customer Two \| Customer Concentration Risk \| Accounts Receivable
Revenues from Contracts and Significant Customers
Concentration risk, percentage		10.30%
Journey
Revenues from Contracts and Significant Customers
Other revenue	$ 619	$ 1,000
Avenue
Revenues from Contracts and Significant Customers
Other revenue	$ 1,404