Annual report pursuant to Section 13 and 15(d)

Convertible Senior Notes - Narrative (Details)

v3.20.4
Convertible Senior Notes - Narrative (Details)
1 Months Ended 2 Months Ended 12 Months Ended
Jan. 28, 2021
USD ($)
Aug. 15, 2019
USD ($)
Dec. 31, 2018
USD ($)
May 22, 2018
USD ($)
$ / shares
shares
Apr. 30, 2020
USD ($)
Jun. 30, 2019
USD ($)
Nov. 30, 2018
shares
Jun. 19, 2018
USD ($)
May 31, 2018
trading_day
Aug. 31, 2014
USD ($)
day
trading_day
$ / shares
shares
Nov. 30, 2018
USD ($)
Aug. 31, 2018
USD ($)
Apr. 30, 2018
USD ($)
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Debt Instrument [Line Items]                                
Net change in fair value of derivatives                               $ 1,800,000
Warrants issued in public offering (shares) | shares                   3,264,643            
Exercise price of convertible bond hedge (USD per share) | $ / shares                   $ 75.05            
Gain (loss) on derivative liabilities                               (1,800,000)
Warrant exercise price (USD per share) | $ / shares                   $ 125.08       $ 1.50    
Value of warrants issued                   $ 11,600,000            
Warrants settled (shares) | shares             525,000                  
Deduction to additional paid-in-capital for warrants settled                               28,300,000
Payments for repurchase of warrants                           $ 0 $ 380,000 30,094,000
Warrants outstanding (shares) | shares                           0    
Debt issuance costs related to the equity component of convertible debt                           $ (3,236,000)    
2023 Convertible Senior Notes                                
Debt Instrument [Line Items]                                
Value of warrants issued                               97,805,000
Convertible Notes                                
Debt Instrument [Line Items]                                
Face amount of debt instrument                           495,280,000 750,000,000  
Total long-term portion of notes payable                           442,293,000 638,959,000  
Convertible Notes | 2019 Convertible Senior Notes                                
Debt Instrument [Line Items]                                
Face amount of debt instrument                   245,000,000.0            
Net proceeds from debt issuance                   $ 239,300,000            
Effective rate (as a percent)                   5.83%            
Convertible debt conversion ratio                   0.0133251            
Debt conversion price per share (USD per share) | $ / shares                   $ 75.05            
Interest on debt instrument (as a percent)                   0.75%            
If-converted value in excess of principal     $ 23,400,000 $ 341,600,000                        
Increase (decrease) in if-converted value in excess of principal                               118,700,000
Notices for conversion           $ 1,000,000.0           $ 195,900,000 $ 21,800,000      
Conversion value over the principal amount           $ 500,000         $ 439,600,000   $ 31,600,000      
Gain (loss) on extinguishment of debt                             (3,200,000)  
Repayments of notes   $ 26,300,000                            
Debt issuance costs related to the liability component of convertible debt   $ 11,900,000                            
Net change in fair value of derivatives                             11,000,000.0 (119,400,000)
Payments for convertible bond hedges                   $ 48,100,000            
Current derivative asset       340,000,000.0                     22,600,000  
Gain (loss) on derivative liabilities                             (11,000,000.0) $ 119,400,000
Proceeds from derivative instrument                             471,200,000  
Convertible Notes | 2019 Convertible Senior Notes | Redemption Period One                                
Debt Instrument [Line Items]                                
Number of trading days | trading_day                   20            
Number of consecutive trading days | trading_day                   30            
Stock price trigger to classify convertible debt as current (as a percent)                   130.00%            
Convertible Notes | 2019 Convertible Senior Notes | Redemption Period Two                                
Debt Instrument [Line Items]                                
Number of trading days | day                   5            
Number of consecutive trading days | trading_day                   10            
Maximum threshold of debt trading price trigger (as a percent)                   98.00%            
Convertible Notes | 2023 Convertible Senior Notes                                
Debt Instrument [Line Items]                                
Face amount of debt instrument       750,000,000                        
Net proceeds from debt issuance       $ 733,100,000                        
Convertible debt conversion ratio                 0.0040244              
Debt conversion price per share (USD per share) | $ / shares       $ 248.48                        
Interest on debt instrument (as a percent)       0.75%                        
Debt issuance costs related to the liability component of convertible debt       $ 13,700,000                        
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                        
Value of warrants issued       $ 90,000,000.0                        
Fair value of the conversion option derivative liability       144,000,000.0                        
Increase (decrease) in derivative liabilities               $ 13,500,000             7,500,000  
Debt issuance costs       $ 16,900,000                        
Debt issuance costs related to the equity component of convertible debt                           (3,200,000) 3,200,000  
Repurchased face amount of debt instrument         $ 234,400,000                 254,700,000    
Repayments of senior debt         203,800,000                 222,800,000    
Accrued interest on repurchased debt         $ 600,000                 600,000    
Loss on repurchase of debt instrument                           2,500,000    
Reduction in debt discount                           $ 35,000,000.0    
Increase (decrease) in derivative assets                             19,200,000  
Convertible Notes | 2023 Convertible Senior Notes | Subsequent Event                                
Debt Instrument [Line Items]                                
Repurchased face amount of debt instrument $ 20,300,000                              
Repayments of senior debt 19,100,000                              
Accrued interest on repurchased debt $ 100,000                              
Convertible Notes | 2023 Convertible Senior Notes | Redemption Period One                                
Debt Instrument [Line Items]                                
Number of trading days | trading_day                 20              
Number of consecutive trading days | trading_day                 30              
Stock price trigger to classify convertible debt as current (as a percent)                 130.00%              
Convertible Notes | 2023 Convertible Senior Notes | Redemption Period Two                                
Debt Instrument [Line Items]                                
Number of trading days | trading_day                 5              
Number of consecutive trading days | trading_day                 10              
Maximum threshold of debt trading price trigger (as a percent)                 98.00%              
Other Expense | Convertible Notes | 2019 Convertible Senior Notes                                
Debt Instrument [Line Items]                                
Net change in fair value of derivatives                             10,200,000  
Gain (loss) on derivative liabilities                             $ (10,200,000)