Annual report pursuant to Section 13 and 15(d)

Notes Payable (Details Textual)

v3.8.0.1
Notes Payable (Details Textual) - USD ($)
1 Months Ended 11 Months Ended 12 Months Ended
Jul. 05, 2017
Jul. 25, 2017
Jun. 26, 2017
Dec. 30, 2016
Sep. 30, 2016
Dec. 31, 2015
Dec. 31, 2017
Dec. 31, 2016
Feb. 28, 2015
Repayments of Notes Payable           $ 0 $ 3,000,000 $ 0  
Debt Instrument, Periodic Payment, Interest   $ 100,000              
Stock Issued During Period, Shares, New Issues         250,000        
Stock Issued During Period, Value, New Issues             948,000 5,000  
Notes Payable           2,703,000 0 2,826,000  
Convertible Notes Payable, Current             0 200,000  
Convertible Debt, Fair Value Disclosures             200,000    
Debt Conversion, Converted Instrument, Shares Issued     49,748            
IPO [Member]                  
Stock Issued During Period, Value, New Issues     $ 6,325,000            
Fortress Biotech, Inc [Member] | IPO [Member]                  
Stock Issued During Period, Shares, New Issues     125,000            
Stock Issued During Period, Value, New Issues     $ 800,000            
NSC Notes Memebers [Member]                  
Repayments of Notes Payable $ 3,000,000           3,000,000    
Debt Instrument, Periodic Payment, Interest $ 2,000                
Interest Expense, Debt           200,000 300,000 400,000  
Debt Instrument, Unamortized Discount           $ 297,000 $ 0 174,000  
NSC Notes Memebers [Member] | IPO [Member]                  
Stock Issued During Period, Value, New Issues     125,000            
NSC Notes Memebers [Member] | Fortress Biotech, Inc [Member]                  
Debt Instrument, Term             10 years    
Debt Instrument, Interest Rate, Stated Percentage             8.00%    
Debt Instrument, Maturity Date, Description             The note matures in 36 months, provided that during the first 24 months Fortress can extend the maturity date by six months. No principal amount will be due for the first 24 months (or the first thirty30 months, if the maturity date is extended).and monthly thereafter until maturity.    
Contingently Issuable Warrants Percentage             25.00%    
Notes Payable             $ 0    
Debt Issuance Costs, Net               $ 200,000  
Debt Instrument, Interest Rate, Effective Percentage               13.10%  
Debt Instrument, Unamortized Discount               $ 100,000  
NSC Notes Memebers [Member] | Avenue Therepeutics parent co [Member]                  
Debt Instrument, Face Amount     $ 3,000,000           $ 10,000,000
Convertible Note Payable [Member] | Fortress Biotech, Inc [Member]                  
Debt Instrument, Term       18 months          
Convertible Notes Payable, Current               $ 200,000  
Debt Instrument Interest Rate Stated Percentage current Year       5.00%          
Debt Instrument Interest Rate Stated Percentage after Twelve Month       8.00%          
Proceeds from Issuance or Sale of Equity       $ 10,000,000          
Net Proceeds From Issuance Of Private Placement After Paying Fees       100,000          
Payments For Placement Fee       30,000          
Payments for Other Fees       4,000          
Professional Fees       14,000          
Class Of Warrant Or Right Value Of Securities Called By Warrants Or Rights       $ 10,000          
Class Of Warrant Or Right Expiration Period       10 years          
Convertible Note Payable [Member] | Fortress Biotech, Inc [Member] | Conversion One [Member]                  
Debt Instrument, Convertible, Terms of Conversion Feature       (a) the lowest price per share at which equity securities of Avenue are sold in such sale less a 33% discount and (b) a per share price based on a pre-offering valuation of $30.0 million divided by the number of common shares outstanding on a fully-diluted basis          
Convertible Note Payable [Member] | Fortress Biotech, Inc [Member] | Conversion Two [Member]                  
Debt Instrument, Convertible, Terms of Conversion Feature       (a) a discount to the price per share being paid in the Sale of Avenue equal to 33% or (b) the quotient resulting from dividing (x) $30.0 million by (y) the fully-diluted common stock of Avenue outstanding immediately prior to the Sale of Avenue (excluding the notes)