XML 79 R59.htm IDEA: XBRL DOCUMENT v3.21.1
Debt - Carrying Value of Liability Component (Details) - Convertible Debt - USD ($)
Jan. 31, 2021
Jan. 31, 2020
Sep. 30, 2018
Convertible Senior Notes Due 2023      
Debt Instrument [Line Items]      
Principal $ 575,000,000 $ 575,000,000 $ 575,000,000.0
Less: extinguishment or conversion (460,000,000) 0  
Unpaid principal 115,000,000 575,000,000  
Less: unamortized debt discount (15,116,000) (101,461,000)  
Less: unamortized transaction costs (1,224,000) (8,218,000)  
Net carrying value of current and noncurrent liability component 98,660,000 465,321,000  
Convertible Senior Notes Due 2024      
Debt Instrument [Line Items]      
Unpaid principal 690,000,000 $ 0  
Less: unamortized debt discount (63,619,000)    
Less: unamortized transaction costs (11,353,000)    
Net carrying value of current and noncurrent liability component $ 615,028,000