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0.25% Convertible Senior Notes, Convertible Note Hedge and Warrant - Additional Information (Detail) - 0.25% Convertible Senior Notes Due 2022 [Member]
3 Months Ended
Mar. 31, 2020
USD ($)
d
May 01, 2020
USD ($)
May 31, 2017
USD ($)
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage     0.25%
Debt instrument, maturity date Jun. 01, 2022    
Debt instrument, convertible, threshold trading days | d 20    
Debt instrument, convertible, threshold consecutive trading days | d 30    
Debt instrument convertible, principal amount $ 2,000    
Private Offering [Member]      
Debt Instrument [Line Items]      
Principal amount of long term debt     $ 350,000,000
Over-Allotment Options [Member]      
Debt Instrument [Line Items]      
Principal amount of long term debt     $ 50,000,000
Minimum [Member]      
Debt Instrument [Line Items]      
Percentage of closing price to trigger debt conversion 130.00%    
Subsequent Event [Member]      
Debt Instrument [Line Items]      
Debt instrument convertible, principal amount   $ 2,000