Quarterly report pursuant to Section 13 or 15(d)

Convertible Senior Notes - Notes Payable (Details)

v3.19.3
Convertible Senior Notes - Notes Payable (Details) - Convertible Notes - USD ($)
Sep. 30, 2019
Dec. 31, 2018
May 31, 2018
Aug. 31, 2014
Notes Payable, Current and Noncurrent [Abstract]        
Fair value of convertible senior notes outstanding (Level 2) $ 625,088,000 $ 713,533,000    
2019 Convertible Senior Notes        
Notes Payable, Current and Noncurrent [Abstract]        
Principal amount of Notes outstanding 0 27,326,000   $ 245,000,000.0
Unamortized discount (including unamortized debt issuance cost) 0 (893,000)    
Total current portion of notes payable 0 26,433,000    
2023 Convertible Senior Notes        
Notes Payable, Current and Noncurrent [Abstract]        
Principal amount of Notes outstanding 750,000,000 750,000,000 $ 750,000,000.0  
Unamortized discount (including unamortized debt issuance cost) (118,467,000) (140,136,000)    
Total long-term portion of notes payable 631,533,000 609,864,000    
Carrying value of equity component of 2023 Notes $ 108,205,000 $ 127,997,000