Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Fair Value of Convertible Debt (Details)

v3.10.0.1
Fair Value Measurements - Fair Value of Convertible Debt (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Fair Value | Non recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Convertible debt fair value $ 564,241 $ 430,301
Carrying Value | Non recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Convertible debt fair value 289,868 281,199
Term Loans | Fair Value | Recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Term Loans 298,049 303,806
Term Loans | Carrying Value | Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Term Loans $ 307,637 $ 317,377