Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities Measured at Fair Value (Details)

v3.10.0.1
Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Thousands
 1 Months Ended 6 Months Ended
Jun. 30, 2018
Apr. 30, 2018
Apr. 30, 2017
Jun. 30, 2018
Dec. 31, 2017
Jun. 30, 2017
Level 2 input            
Volatility       38.00%    
Interest rate       2.30%    
Dividend yield       0.00%    
Zero-strike call option            
Assets and Liabilities Measured at Fair Value            
Derivative settlement proceeds $ 46,500          
Total | Recurring            
Assets and Liabilities Measured at Fair Value            
Cash equivalents 34,714     $ 34,714 $ 76,304  
Derivative Asset 45,747     45,747    
Quoted prices in active markets for identical assets (Level 1) | Recurring            
Assets and Liabilities Measured at Fair Value            
Cash equivalents 34,714     34,714 $ 76,304  
Significant other observable inputs (Level 2) | Recurring            
Assets and Liabilities Measured at Fair Value            
Derivative Asset $ 45,747     $ 45,747    
Series C common stock | Zero-strike call option | Call Option            
Assets and Liabilities Measured at Fair Value            
Derivative underlying share amount 632,911 610,325 600,242 632,911   600,242
Derivative premium paid $ 46,500 $ 47,800 $ 50,000