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

Related Party Transactions - Schedule of The Effective Date and Annual Management Services agreement Fee (Income) Expense (Details)

Related Party Transactions - Schedule of The Effective Date and Annual Management Services agreement Fee (Income) Expense (Details)	3 Months Ended
	Mar. 31, 2020 USD ($)
Helocyte Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Mar. 20, 2015
Avenue [Member]
Related Party Transaction [Line Items]
Annual Consulting Fee Payable Effective Date	Feb. 17, 2015
Mustang Bio, Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Mar. 13, 2015
Checkpoint [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Mar. 17, 2015
Cellvation Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Oct. 31, 2016
Baergic[Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Mar. 09, 2017
Cyprium Bio sciences Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Mar. 13, 2017
Aevitas Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ 500
Annual Consulting Fee Payable Effective Date	Jul. 28, 2017
Tamid Bio sciences Inc [Member]
Related Party Transaction [Line Items]
Annual Consulting Fee Payable Effective Date	Nov. 30, 2017
Fortress Biotech Inc [Member]
Related Party Transaction [Line Items]
Annual Management Services Agreement Fee Income expense	$ (3,500)