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

Debt and Interest- Additional Information (Detail)

v3.10.0.1

Debt and Interest- Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 12, 2018	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Debt [Line Items]
Payments of Financing Costs			$ 0	$ 1,939
Opus Credit Facility [Member]
Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			12.00%
Debt instrument Expiration Period	Sep. 14, 2019				Sep. 14, 2018
Venture Notes [Member]
Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Debt Instrument, Face Amount		$ 21,700
Debt Instrument, Term			36 months
Debt Instrument, Maturity Date, Description			The notes mature 36 months from issuance, provided that during the first 24 months the Company may extend the maturity date by six months.
NSC [Member] \| Venture Notes [Member]
Debt [Line Items]
Warrant On Sale Price Of Note Percentage			25.00%
Payments of Financing Costs		$ 1,700
Class of Warrant or Right, Expiration Period			10 years
Aevitas Therapeutics, Inc [Member] \| Venture Notes [Member]
Debt [Line Items]
Proceeds from Notes Payable			$ 1,400
Tamid Bio, Inc [Member] \| Venture Notes [Member]
Debt [Line Items]
Proceeds from Notes Payable			1,100
Cellvation [Member] \| Venture Notes [Member]
Debt [Line Items]
Proceeds from Notes Payable			1,200
Cyprium [Member] \| Venture Notes [Member]
Debt [Line Items]
Proceeds from Notes Payable			$ 1,000

- Definition

The expiration period of warrants or rights.

+ References

No definition available.

+ Details

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- Definition

Expiration Period ofDebtinstrument.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

It represents the percentage rate of warrants which are issued on sale price of notes.

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

The cash outflow for loan and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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Balance Type:	credit
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- Definition

The cash inflow from a borrowing supported by a written promise to pay an obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

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