Fortress Biotech, Inc. Quarterly report pursuant to Section 13 or 15(d)

Debt and Interest (Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Debt Instrument [Line Items]
Interest expense, interest	$ 2,839	$ 3,724	$ 7,397	$ 7,770
Amortization of fees	554	720	1,500	1,623
Interest expense, Total	3,393	4,444	8,897	9,393
Unamortized debt discount fees	9,885		9,885		$ 7,063
Debt prepayment penalties			0	450
Letter of Credit [Member]
Debt Instrument [Line Items]
Interest expense, interest	11	14	37	37
Amortization of fees	0	0	0	0
Interest expense, Total	11	14	37	37
Oaktree Note [Member]
Debt Instrument [Line Items]
Interest expense, interest	1,406	2,136	4,171	5,455
Amortization of fees	395	342	1,126	975
Interest expense, Total	1,801	2,478	5,297	6,430
Partner Company Dividend Payable [Member]
Debt Instrument [Line Items]
Interest expense, interest	0	365	0	628
Amortization of fees	0	0	0	0
Interest expense, Total	0	365	0	628
Partner Company Convertible Preferred Shares [Member]
Debt Instrument [Line Items]
Interest expense, interest	0	1,034	0	1,034
Amortization of fees	0	378	0	648
Interest expense, Total	0	1,412	0	1,682
Partner company installment payments - licenses [Member]
Debt Instrument [Line Items]
Interest expense, interest	201	175	619	616
Amortization of fees	0	0	0	0
Interest expense, Total	201	175	619	616
Partner Company Notes Payable [Member]
Debt Instrument [Line Items]
Interest expense, interest	1,221	0	2,570	0
Amortization of fees	159	0	374	0
Interest expense, Total	$ 1,380	$ 0	$ 2,944	$ 0