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

Changes in Fair Value of Financial Instruments (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014	$ 4,160
Purchases	0
Change in fair value of investment	1,407
Balance at June 30, 2015	5,567
CB Pharma Acquisitions Corp [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014	3,910
Purchases	0
Change in fair value of investment	1,407
Balance at June 30, 2015	5,317
Other Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014	250
Purchases	0
Change in fair value of investment	0
Balance at June 30, 2015	$ 250