XML 62 R51.htm IDEA: XBRL DOCUMENT v3.7.0.1
Long-term Debt (Details)
$ / shares in Units, shares in Millions
1 Months Ended 3 Months Ended
Dec. 31, 2016
USD ($)
shares
$ / shares
Mar. 31, 2017
USD ($)
Mar. 31, 2016
USD ($)
Debt Instrument [Line Items]      
Amortization of deferred financing costs   $ 229,000 $ 0
Senior Notes | Convertible Senior Notes due 2021      
Debt Instrument [Line Items]      
Face amount $ 125,000,000.0 125,000,000  
Interest rate 2.00%    
Proceeds from issuance of debt $ 120,400,000    
Debt issuance costs $ 4,600,000    
Repurchase price due to fundamental change as percentage of principal amount 100.00%    
Interest expense   600,000  
Amortization of deferred financing costs   200,000  
Debt conversion denominator shares per principal amount $ 1,000    
Convertible debt carrying value $ 120,283,000 $ 120,706,000  
Senior Notes | Convertible Senior Notes due 2021 | Class A | Common Stock      
Debt Instrument [Line Items]      
Initial conversion rate per $1000 principal amount 0.0416082    
Conversion price (in dollars per share) | $ / shares $ 24.03    
Initial conversion amount (in shares) | shares 5.2