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

Revenues from Contracts and Significant Customers - Company's product revenue (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Sales Revenue, Goods, Net									$ 23,376	$ 15,520
Total Revenue	$ 8,991	$ 5,173	$ 6,815	$ 5,903	$ 7,543	$ 2,520	$ 4,404	$ 2,778	26,882	17,245
Targadox [Member]
Sales Revenue, Goods, Net									21,225	13,752
Other Branded Revenue [Member]
Sales Revenue, Goods, Net									2,151	1,768
TGTX [Member]
Sales Revenue, Goods, Net									$ 3,506	$ 1,725