Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Class A Redeemable Convertible Preferred Stock - Additional Information (Detail)

v3.10.0.1
Class A Redeemable Convertible Preferred Stock - Additional Information (Detail) - USD ($)
Jun. 25, 2018
Jun. 24, 2018
Dec. 22, 2016
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 30, 2015
Temporary Equity [Line Items]                
Preferred stock, shares issued       0 6,864,000      
Preferred stock, par value       $ 0.001 $ 0.001      
Preferred stock, shares outstanding       0 6,864,000      
Series A Redeemable Convertible Preferred Stock                
Temporary Equity [Line Items]                
Preferred stock, shares issued               14,666,667
Preferred stock, par value     $ 7,500,000         $ 7.50
Preferred stock, liquidation preference     $ 49,500,000         $ 110,000,000.0
Preferred stock, liquidation amount at redemption           $ 100,000,000.0    
Preferred stock, shares redeemed     8,066,667          
Preferred stock, redemption amount     $ 55,000,000.0          
Preferred stock redemption price per share (in dollars per share) $ 7.30   $ 6,820,000          
Preferred stock, redemption discount 4.55%   9.09%          
Preferred stock, redemption price, accrued and unpaid dividends, addition price per share $ 0.14              
Preferred stock, shares outstanding       0 6,864,000 6,600,000 14,666,667  
Preferred stock, carrying amount attributable to parent   $ 37,800,000            
Preferred stock, recognized amount of beneficial conversion feature   $ 21,300,000            
Payments for repurchase of preferred stock $ 50,100,000              
Temporary equity, par value (in dollars per share)     $ 32,900,000         $ 73,200,000
Shares issued (in dollars per share)               $ 4.99
Preferred stock, issue discount     16,600,000         $ 36,800,000
Preferred stock, beneficial conversion feature     $ 20,100,000         $ 44,700,000
Series A Redeemable Convertible Preferred Stock | Payment In Kind                
Temporary Equity [Line Items]                
Preferred stock, shares issued         264,000