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

Quarterly report [Sections 13 or 15(d)]

Stockholders' Equity (Capital Raises) (Narrative) (Details)

Stockholders' Equity (Capital Raises) (Narrative) (Details) - USD ($)				1 Months Ended							3 Months Ended	5 Months Ended	9 Months Ended
	Jan. 15, 2026	Jun. 12, 2024	Dec. 30, 2022	Aug. 31, 2025	Apr. 30, 2025	Mar. 31, 2025	Feb. 28, 2025	Jan. 31, 2025	May 31, 2024	Feb. 28, 2023	Sep. 30, 2026	May 31, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Stockholders' Equity
Stock offering, number of shares issued													0
Proceeds from issuance of Common stock														$ 1,008,000
Exercise of warrants for cash													$ 1,218,000	$ 2,279,000
Sale of stock, net proceeds			$ 150,000,000
Warrants exercised, Number of shares													694,296
Outstanding warrants											12,737,206		12,737,206		13,431,502
Common Stock, par value											$ 0.001		$ 0.001		$ 0.001
AcqCorpLXII warrants
Stockholders' Equity
Gain (loss) on contingent consideration											$ 12,000
Checkpoint \| Founder agreement
Stockholders' Equity
Stock offering, number of shares issued												18,500
Shares issued (in percent)								2.50%
Checkpoint \| 2025 Warrant
Stockholders' Equity
Exercise of warrants for cash					$ 9,200,000	$ 36,000,000		$ 2,100,000
Number of shares issued upon exercise of warrants					3,256,269	21,691,003		740,000
Exercise price of warrants					$ 2.82	$ 1.66		$ 2.84
Avenue \| Unregistered warrants
Stockholders' Equity
Net proceeds									$ 3,900,000
AcqCorpLXII \| AcqCorpLXII warrants
Stockholders' Equity
Exercise price of warrants											$ 0.039		$ 0.039
Number of warrants to purchase shares											347,420		347,420
Warrant expiration term											10 years		10 years
At the Market Offering
Stockholders' Equity
Stock offering, number of shares issued				3,750,000										500,000
Stock purchase, price per share														$ 1.94
Proceeds from issuance of Common stock														$ 1,000,000
At the Market Offering \| Mustang \| Founder agreement
Stockholders' Equity
Stock offering, number of shares issued													0	54,000
Sale of stock, net proceeds														$ 600,000
At the Market Offering \| Avenue \| Founder agreement
Stockholders' Equity
Stock offering, number of shares issued														23,474
Shares issued (in percent)														2.50%
At the Market Offering \| Avenue \| Unregistered warrants
Stockholders' Equity
Shares issued														900,000
Net proceeds														$ 2,100,000
Shelf Registration Statement
Stockholders' Equity
Stock offering, number of shares issued													0	1,800,000
Stock offering, aggregate offering permitted by the agreement	$ 150,000,000
Sale of stock, net proceeds														$ 10,900,000
Shelf Registration 2024 Statement
Stockholders' Equity
Amount available for future stock offerings											$ 42,100,000		$ 42,100,000
Shelf Registration 2024 Statement \| Mustang
Stockholders' Equity
Stock offering, aggregate offering permitted by the agreement													$ 34,200,000
Shelf Registration 2024 Statement \| Maximum \| Mustang
Stockholders' Equity
Stock offering, aggregate offering permitted by the agreement		$ 40,000,000
February 2025 Equity Offering \| Checkpoint \| Founder agreement
Stockholders' Equity
Stock offering, number of shares issued														127,140
Shares issued (in percent)							2.50%
February 2025 Equity Offering \| Mustang
Stockholders' Equity
Stock offering, number of shares issued							495,000
Stock purchase, price per share							$ 3.01
Exercise price of warrants							$ 3.01
Number of warrants to purchase shares							2,162,807
Sale of stock, net proceeds							$ 6,800,000
Common Stock, par value							$ 0.0001
February 2025 Equity Offering \| Mustang \| Series C-1 warrants
Stockholders' Equity
Number of warrants to purchase shares							2,657,807
Warrant expiration term							5 years
February 2025 Equity Offering \| Mustang \| Series C-2 warrants
Stockholders' Equity
Number of warrants to purchase shares							2,657,807
Warrant expiration term							24 months
February 2025 Equity Offering \| Mustang \| Pre funded warrants
Stockholders' Equity
Stock purchase, price per share							$ 3.0099
Exercise price of warrants							$ 0.0001
Direct offering
Stockholders' Equity
Corporate development transaction, period										5 years
Shares issued										1,100,000
Shares issued, price per share										$ 12.53
Sale of stock, net proceeds										$ 13,300,000