• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Long-Term Debt - Summary of Principal and Interest Payment Terms of Convertible Senior Notes (Detail)
12 Months Ended
Dec. 31, 2017
3.875% Convertible Senior Notes [Member]  
Debt Instrument [Line Items]  
Convertible senior notes, interest payment terms Semiannually in arrears: March 15 and September 15
4.25% Convertible Senior Notes [Member]  
Debt Instrument [Line Items]  
Convertible senior notes, interest payment terms Semiannually in arrears: March 1 and September 1