XML 67 R54.htm IDEA: XBRL DOCUMENT v3.8.0.1
Carrying Value of Convertible Senior Notes (Detail) - 2.125% Convertible Senior Notes due 2021 - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Debt Instrument [Line Items]    
Principal amount $ 114,989 $ 115,000
Unamortized debt discount (12,513) (13,395)
Unamortized debt issuance costs (2,200) (2,355)
Total convertible senior notes $ 100,276 $ 99,250