Quarterly report pursuant to Section 13 or 15(d)

Convertible Senior Notes - Narrative (Details)

v3.20.1
Convertible Senior Notes - Narrative (Details)
1 Months Ended 3 Months Ended
Mar. 31, 2020
USD ($)
May 31, 2018
USD ($)
d
$ / shares
shares
Mar. 31, 2020
USD ($)
Mar. 31, 2019
USD ($)
Feb. 29, 2020
USD ($)
Dec. 31, 2019
USD ($)
Debt Instrument [Line Items]            
Gain (loss) on extinguishment of debt     $ 659,000 $ 0    
Increase (decrease) in equity component of convertible debt     (2,745,000)      
Convertible Notes | 2023 Convertible Senior Notes            
Debt Instrument [Line Items]            
Aggregate principal amount outstanding $ 515,560,000 $ 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 515,600,000   $ 515,600,000   $ 234,400,000  
Repayments of notes 203,800,000          
Gain (loss) on extinguishment of debt 700,000          
Increase (decrease) in debt discount (32,700,000)          
Increase (decrease) in 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%