Quarterly report pursuant to Section 13 or 15(d)

Convertible Senior Notes - Notes Payable (Details)

v3.19.2
Convertible Senior Notes - Notes Payable (Details) - Convertible Notes - USD ($)
Jun. 30, 2019
Dec. 31, 2018
May 31, 2018
Aug. 31, 2014
2019 Convertible Senior Notes        
Notes Payable, Current and Noncurrent [Abstract]        
Principal amount of Notes outstanding $ 27,323,000 $ 27,326,000   $ 245,000,000.0
Unamortized discount (including unamortized debt issuance cost) (236,000) (893,000)    
Total current portion of notes payable 27,087,000 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) (125,791,000) (140,136,000)    
Total long-term portion of notes payable 624,209,000 609,864,000    
Fair value of convertible senior notes outstanding (Level 2) $ 689,172,000 $ 713,533,000