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

Annual report pursuant to Section 13 and 15(d)

Debt and Interest (Narrative) (Details)

Debt and Interest (Narrative) (Details)									1 Months Ended				12 Months Ended
Debt and Interest (Narrative) (Details)	Dec. 27, 2022 USD ($) $ / shares shares	Mar. 04, 2022 USD ($) $ / shares	Jan. 12, 2022 USD ($)	Nov. 12, 2021 shares	Oct. 12, 2021 USD ($)	Sep. 30, 2021 $ / shares shares	Sep. 28, 2021 USD ($)	Aug. 27, 2020 USD ($) shares	Feb. 28, 2023 USD ($) item	Aug. 31, 2022 USD ($)	Jan. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Debt Instrument [Line Items]
Proceeds from debt													$ 47,112,000	$ 0
Total notes payable													91,730,000	42,937,000
Unamortized debt discount fees													9,320,000	7,063,000
Debt instrument, interest expense													10,417,000	11,394,000
Repayments of debt													0	10,450,000
Debt prepayment penalties													0	450,000
Fair Value Adjustment of Warrants													(1,129,000)	447,000
Amortization of debt discount													2,065,000	3,914,000
Contingent Payment Warrant [Member]
Debt Instrument [Line Items]
Fair Value Adjustment of Warrants														447,000
EWB Amendment [Member]
Debt Instrument [Line Items]
Amount outstanding													2,900,000
Debt instrument term			4 years
Maximum borrowing capacity			$ 10,000,000.0
Prime Rate \| EWB Amendment [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			0.70%
Letter of Credit [Member]
Debt Instrument [Line Items]
Debt instrument, interest expense													$ 54,000	51,000
IDB Note Payable [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate													2.00%
Letter of credit, amount outstanding													$ 2,700,000	2,200,000
Oaktree Note [Member]
Debt Instrument [Line Items]
Debt instrument face amount								$ 60,000,000.0
Debt instrument, interest expense													$ 5,561,000	6,897,000
Debt instrument, stated interest rate								11.00%					11.00%
Debt prepayment penalties														500,000
Debt maturity date								Aug. 27, 2025
Percentage of upfront commitment fee								3.00%
Upfront Commitment Fee								$ 1,800,000
Debt issuance fees													$ 8,700,000
Agency fees payment								35,000
Payment of expenses to third parties								$ 2,500,000
Warrants issued \| shares								1,749,450
Warrants, fair value								$ 4,400,000
Amortization of debt discount													$ 1,500,000	1,300,000
EWB Term Loan [Member]
Debt Instrument [Line Items]
Proceeds from debt										$ 5,000,000.0	$ 15,000,000.0
Debt instrument face amount			$ 20,000,000.0
Debt, effective interest rate													9.64%
Debt instrument, stated interest rate													9.23%
Debt instrument term			4 years
Remaining borrowing capacity													$ 7,100,000
EWB Term Loan [Member] \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate			1.73%
Runway Note [Member]
Debt Instrument [Line Items]
Proceeds from debt		$ 30,000,000.0
Debt instrument face amount		$ 75,000,000.0
Debt, effective interest rate													13.40%
Debt instrument, stated interest rate		8.75%											13.40%
Debt prepayment penalties		$ 1,100,000
Percentage of upfront commitment fee		1.00%
Upfront Commitment Fee		$ 300,000
Percent of Outstanding Loan Principal Amount for Calculation of Repayment Change		3.50%
Credit facility, amount outstanding		$ 30,000,000
Deposit on commitment fee		75,000
Amortization of debt discount													$ 500,000
Other cash fees		2,700,000
Runway Note [Member] \| Financial Milestones [Member]
Debt Instrument [Line Items]
Debt instrument face amount		$ 45,000,000.0
Basis spread on variable rate		0.50%
Runway Note [Member] \| Minimum
Debt Instrument [Line Items]
Debt, effective interest rate		9.25%
Partner Company Promissory Note
Debt Instrument [Line Items]
Debt instrument, interest expense													4,021,000	0
Warrants to Purchase Common Stock [Member] \| Runway Note [Member]
Debt Instrument [Line Items]
Warrants, fair value		$ 400,000
Class of warrant or right value of securities called by warrants or rights		748,036
Exercise price of warrants \| $ / shares		$ 0.8021
Warrants to Purchase Common Stock [Member] \| Risk Free Interest Rate [Member] \| Runway Note [Member]
Debt Instrument [Line Items]
Fair value of warrants assumptions		0.0174
Warrants to Purchase Common Stock [Member] \| Expected Volatility [Member] \| Runway Note [Member]
Debt Instrument [Line Items]
Fair value of warrants assumptions		0.573
Warrants to Purchase Common Stock [Member] \| Expected Term [Member] \| Runway Note [Member]
Debt Instrument [Line Items]
Fair value of warrants assumptions		10
Caelum
Debt Instrument [Line Items]
Repayments of debt					$ 10,500,000
Debt prepayment penalties							$ 500,000
Prepayment amount on monetization							$ 10,000,000
Caelum \| Interest Expense [Member]
Debt Instrument [Line Items]
Debt prepayment penalties														$ 500,000
Journey \| Placement Agent Warrants [Member]
Debt Instrument [Line Items]
Number of shares issued related to the conversion of warrants \| shares														111,567
Percentage of common stock for which the Preferred A is exchanged														5.00%
Warrant expiration term														5 years
Journey \| Promissory Note [Member]
Debt Instrument [Line Items]
Share price per share \| $ / shares						$ 10.00
Debt Conversion, Converted Instrument, Shares Issued \| shares						1,476,044
Journey \| 8% Cumulative Convertible Class A Preferred Offering
Debt Instrument [Line Items]
Sale of stock, net proceeds													$ 17,000,000.0
Percentage of common stock into which the Journey Preferred A converts												15.00%
Common stock's average 10-day trading price discount percentage													7.50%
Stock offering, number of shares issued \| shares													758,680	81,985
Stock offering, gross proceeds													$ 19,000,000.0
Stock offering, aggregate fees paid													1,900,000
Stock offering other fees paid													$ 100,000
Stock offering, price per share \| $ / shares													$ 25.00	$ 10.00
Preferred Stock, dividend rate percentage												8.00%
Number of common stocks converted from preferred stocks \| shares				2,231,346
Journey \| 8% Cumulative Convertible Class A Preferred Offering \| Dividend Paid [Member]
Debt Instrument [Line Items]
Stock offering, number of shares issued \| shares														253,815
Stock offering, gross proceeds														$ 800,000
Journey \| 8% Cumulative Convertible Class A Preferred Offering \| Preferred Stock has not been Converted into Journey Common Stock [Member]
Debt Instrument [Line Items]
Preferred stock offering, aggregate proceeds												$ 25,000,000.0
Journey \| 8% Cumulative Convertible Class A Preferred Offering \| Maximum
Debt Instrument [Line Items]
Preferred stock offering, aggregate proceeds												30,000,000.0
Journey \| 8% Cumulative Convertible Class A Preferred Offering \| Minimum
Debt Instrument [Line Items]
Preferred stock offering, aggregate proceeds												$ 12,500,000
Urica \| 8% Cumulative Convertible Class B Preferred Offering
Debt Instrument [Line Items]
Sale of stock, net proceeds	$ 2,200,000								$ 800,000
Warrants, fair value	$ 100,000
Common stock's average 10-day trading price discount percentage	7.50%
Stock offering, number of shares issued \| shares	101,334
Number of Additional Closings of Shares Offering \| item									2
Stock offering, gross proceeds	$ 2,500,000								$ 900,000
Stock offering, aggregate fees paid	$ 300,000								$ 100,000
Stock offering, price per share \| $ / shares	$ 25.00
Preferred Stock, dividend rate percentage	8.00%
Aggregate gross proceeds from convertible preferred stock	$ 20,000,000
Percentage of discounted price	20.00%
Percentage of placement agents fees	10.00%
Percentage of number of securities into which warrants converted	10.00%
Percentage of common stock which can be exchanged for preferred stock	10.00%