Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Exclusive of National Financial Instruments Measured at Fair Value on Recurring Basis (Details)

v3.19.2
Fair Value Measurements - Exclusive of National Financial Instruments Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Assets    
Fair value of investment $ 11,193  
Total 11,193  
Liabilities    
Liabilities   $ 10,905
Warrants to Purchase Common Stock [Member]    
Liabilities    
Liabilities   991
Caelum Convertible Notes [Member]    
Liabilities    
Liabilities   9,914
Fair Value, Inputs, Level 3 [Member]    
Assets    
Fair value of investment 11,193  
Total $ 11,193  
Liabilities    
Liabilities   10,905
Fair Value, Inputs, Level 3 [Member] | Warrants to Purchase Common Stock [Member]    
Liabilities    
Liabilities   991
Fair Value, Inputs, Level 3 [Member] | Caelum Convertible Notes [Member]    
Liabilities    
Liabilities   $ 9,914