Quarterly report pursuant to Section 13 or 15(d)

Convertible Senior Notes - Narrative (Details)

v3.20.2
Convertible Senior Notes - Narrative (Details)
1 Months Ended 3 Months Ended 9 Months Ended
Mar. 31, 2020
USD ($)
May 31, 2018
USD ($)
d
$ / shares
shares
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Debt Instrument [Line Items]              
Gain (loss) on extinguishment of debt         $ 659,000 $ 0  
Adjustments to additional paid in capital, equity component of convertible debt     $ 23,000 $ 2,745,000      
Convertible Notes | 2023 Convertible Senior Notes              
Debt Instrument [Line Items]              
Aggregate principal amount outstanding   $ 750,000,000.0     515,560,000   $ 750,000,000
Interest rate (as a percent)   0.75%          
Proceeds from debt, net of issuance costs   $ 733,100,000          
Initial conversion rate (shares per $1,000)   0.0040244          
Initial conversion price (USD per share) | $ / shares   $ 248.48          
Debt issuance costs         16,900,000    
Debt premium         13,700,000    
Long-term debt $ 234,400,000     $ 234,400,000 515,600,000    
Repayments of notes 203,800,000            
Accrued Interest $ 600,000            
Gain (loss) on extinguishment of debt         700,000    
Increase (decrease) in debt discount         32,700,000    
Adjustments to additional paid in capital, equity component of convertible debt         $ 2,700,000    
Warrants issued in public offering (shares) | shares   3,018,327          
Payments for convertible bond hedges   $ 140,300,000          
Warrant exercise price (USD per share) | $ / shares   $ 315.38          
Warrant derivative in connection with Notes   $ 90,000,000.0          
Convertible Notes | 2023 Convertible Senior Notes | Debt Instrument, Redemption, Period One              
Debt Instrument [Line Items]              
Threshold trading days | d   20          
Consecutive trading days | d   30          
Stock price trigger to classify convertible debt as current (as a percent)   130.00%          
Convertible Notes | 2023 Convertible Senior Notes | Debt Instrument, Redemption, Period Two              
Debt Instrument [Line Items]              
Threshold trading days | d   5          
Consecutive trading days | d   10          
Maximum threshold of debt trading price trigger (as a percent)   98.00%