Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies - Additional Information (Details)

v3.19.2
Significant Accounting Policies - Additional Information (Details) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jan. 01, 2019
Jun. 30, 2019
Dec. 31, 2018
Mar. 17, 2015
Equity Method Investment, Annual Equity Fee, Percentage       2.50%
Fortress Biotech, Inc [Member]        
Equity Method Investment, Annual Equity Fee, Percentage 2.50%      
Stock Issued During Period, Shares, New Issues 960,428 27,195    
Research and Development Expense [Member]        
Stock Issued During Period, Value, Issued for Services     $ 1.7