Quarterly report pursuant to Section 13 or 15(d)

Debt - Convertible Debt (Details)

v3.19.3
Debt - Convertible Debt (Details) - Convertible Senior Notes - Convertible Senior Notes Due November 2022 - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
May 23, 2017
Convertible Debt [Abstract]            
Principal amount $ 344,995,000   $ 344,995,000   $ 345,000,000 $ 345,000,000.0
Unamortized discount (38,085,000)   (38,085,000)   (46,235,000)  
Unamortized debt issuance costs (4,878,000)   (4,878,000)   (5,922,000)  
Convertible notes payable, net (non current) 302,032,000   302,032,000   292,843,000  
Equity component 61,390,000   61,390,000   $ 61,390,000 $ 62,500,000
Interest Expense, Debt [Abstract]            
Contractual interest expense 1,294,000 $ 1,294,000 3,881,000 $ 3,881,000    
Amortization of debt discount 2,756,000 2,599,000 8,149,000 7,685,000    
Amortization of debt issuance costs 353,000 333,000 1,043,000 984,000    
Interest expense, net $ 4,403,000 $ 4,226,000 $ 13,073,000 $ 12,550,000