Annual report pursuant to Section 13 and 15(d)

Redeemable Convertible Preferred Stock - Additional Information (Detail)

v3.19.1
Redeemable Convertible Preferred Stock - Additional Information (Detail) - shares
12 Months Ended
Aug. 01, 2017
Dec. 31, 2017
Common Stock    
Temporary Equity [Line Items]    
Preferred stock converted into common stock in connection with merger, shares 13,029,297  
Conversion of preferred stock to common stock of merged entity, shares 9,220,478 9,220,478
Convertible Preferred Stock    
Temporary Equity [Line Items]    
Temporary equity, Amount of shares of preferred stock outstanding that were converted to common stock in connection with merger 9,116,405 9,116,405
Conversion of preferred stock dividends to common stock in connection with merger, shares 3,912,892