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Long Term Debt - Additional Information (Detail)
3 Months Ended 12 Months Ended
May 24, 2016
USD ($)
d
$ / shares
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Debt Instrument [Line Items]      
Proceeds from issuance of convertible senior notes, net of costs   $ 111,100,000  
Accretion of the debt discount   $ 970,000  
2.125% Convertible Senior Notes due 2021      
Debt Instrument [Line Items]      
Notes issued $ 115,000,000    
Notes, interest rate 2.125% 2.125%  
Notes, frequency of periodic payment   Semi-annually  
Notes, date of first required payment   Dec. 01, 2016  
Notes, due date   Jun. 01, 2021 Jun. 01, 2021
Notes conversion ratio per $1,000 principal amount 31.1813    
Notes initial conversion price | $ / shares $ 32.07    
Debt covenants debt default holder percent to declare all notes due minimum 25.00%    
Number of days within which entity fails to satisfy obligations considered as event of default 270 days    
Notes issued, fair value $ 96,289,000    
Contractual coupon interest   $ 611,000  
Accretion of the debt discount   825,000  
Amortization of the debt issuance costs   $ 145,000  
Effective interest rate on the Notes   6.60%  
Notes, carrying value   $ 96,242,000 $ 95,272,000
Fair value of the note   $ 144,300,000  
2.125% Convertible Senior Notes due 2021 | On any business day on or after June 5, 2019 and prior to the maturity date      
Debt Instrument [Line Items]      
Notes threshold percentage of stock price trigger 130.00%    
Notes threshold trading days | d 20    
Notes threshold consecutive trading days 30 days    
Notes redemption price 100.00%