XML 112 R59.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Convertible Senior Notes - Summary of Net Carrying Amount of Liability Component of Notes (Detail) - USD ($)
Dec. 31, 2019
Dec. 31, 2018
Debt Disclosure [Abstract]    
Principal $ 460,000,000  
Unamortized discount (67,350,000)  
Unamortized issuance cost (5,761,000)  
Net carrying amount $ 386,889,000 $ 366,552,000