Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Details)

v3.19.2
Stockholders' Equity - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended
Apr. 30, 2019
Apr. 19, 2019
May 31, 2019
Apr. 30, 2019
Mar. 29, 2019
Aug. 31, 2018
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common Stock, Shares, Issued               39,454,316   39,454,316   26,610,183
Proceeds from Issuance of Common Stock                   $ 31,625    
Shelf Registration Statement Remaining Unissued Capital               $ 20,900   20,900    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized             5,000,000   5,000,000   5,000,000  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized             3,000,000          
General and Administrative Expense.               $ 3,189 $ 1,683 5,533 $ 3,793  
Annual Fees Expenses On Founders Agreement                   400    
Proceeds From Horizon Notes                   $ 15,000 $ 0  
City of Hope                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Conversion of Stock, Shares Issued       137,608                
Market Offering                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common Stock, Shares, Issued               3,500,000   3,500,000   0
Share price               $ 6.42   $ 6.42    
Shelf Registration Statement, Aggregate Fee Paid                   $ 500    
Proceeds from Issuance of Common Stock                   22,000    
Proceeds From Horizon Notes               $ 22,500   $ 22,500    
Market Offering | Maximum                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Shelf Registration Statement, Maximum Authorized Common Stock Issuance, Value           $ 75,000            
Agent commission (as a percent)           3.00%            
Public Offering [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common Stock, Shares, Issued 6,875,000     6,875,000                
Share price $ 4.00     $ 4.00                
Proceeds from Issuance of Common Stock $ 29,500                      
Proceeds From Horizon Notes       $ 31,600                
Aggregate Fees, Public Offering $ 2,100                      
Public Offering [Member] | Maximum                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Option to purchase additional shares       1,031,250                
Incentive Plan 2016 [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period                   10 years    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized               1,987,439   1,987,439    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized                   2,000,000    
Employee Stock Option                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Allocated Share-based Compensation Expense                   $ 800    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term                   1 year 7 months 6 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number               310,419   310,419    
Employee Stock Option | Restricted Stock [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Allocated Share-based Compensation Expense                   $ 1,600    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term                   2 years 2 months 12 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number               68,160   68,160    
Employee Stock Option | Restricted Stock Units (RSUs)                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Allocated Share-based Compensation Expense                   $ 2,900    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term                   1 year 10 months 24 days    
Common Shares                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Stock Issued During Period, Shares, Issued for Services                   709,314 834,756  
Conversion of Stock, Shares Converted       137,608       137,608   137,608    
Class A Common Shares                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common Stock, Shares, Issued               862,392   862,392   1,000,000
Stock Issued During Period, Shares, Issued for Services                   0 0  
Conversion of Stock, Shares Converted       137,608       (137,608)   (137,608)    
Class A Common Shares | City of Hope                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Conversion of Stock, Shares Converted       137,608                
Fortress Biotech, Inc                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Stock Issued During Period, Shares, Issued for Services         108,069              
Shares Of Common Stock, Percentage         2.50%              
Proceeds From Horizon Notes   $ 22,500                    
Fortress Biotech, Inc | Market Offering                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Stock Issued During Period, Shares, Issued for Services       87,656                
Shares Of Common Stock, Percentage 2.50%     2.50%                
General and Administrative Expense.                   $ 500    
Proceeds From Horizon Notes       $ 22,500                
Fortress Biotech, Inc | Public Offering [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common Stock, Shares, Issued     197,656                  
Shares Of Common Stock, Percentage     2.50%                  
General and Administrative Expense.     $ 800                  
Proceeds From Horizon Notes     $ 31,600