Fortress Biotech, Inc. Quarterly report [Sections 13 or 15(d)]

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liabilities	$ 0	$ 214
Avenue \| Common Stock Warrant
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liabilities	16,000	16,000
Placement Agent Warrants \| Checkpoint \| December 2022 Offering
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock warrant liabilities	$ 0	$ 200