Quarterly report pursuant to Section 13 or 15(d)

Debt - Convertible Debt (Details)

v3.20.1
Debt - Convertible Debt (Details) - Convertible Senior Notes - Convertible Senior Notes Due November 2022 - USD ($)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
May 23, 2017
Convertible Debt [Abstract]        
Principal amount $ 344,995,000   $ 344,995,000 $ 345,000,000.0
Unamortized discount (32,449,000)   (35,287,000)  
Unamortized debt issuance costs (4,157,000)   (4,520,000)  
Convertible notes, net 308,389,000   305,188,000  
Equity component, net of issuance costs and deferred tax: 61,390,000   $ 61,390,000 $ 62,500,000
Interest Expense, Debt [Abstract]        
Contractual interest expense 1,294,000 $ 1,294,000    
Amortization of debt discount 2,838,000 2,676,000    
Amortization of debt issuance costs 363,000 343,000    
Interest expense, net $ 4,495,000 $ 4,313,000