Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Activity of Restricted Stock Units (Detail)

v3.8.0.1
Stock-Based Compensation - Summary of Activity of Restricted Stock Units (Detail) - Restricted Stock Units [Member]
9 Months Ended
Sep. 30, 2017
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of restricted stock units outstanding, Unvested beginning balance | shares 0
Number of restricted stock units outstanding, Granted | shares 1,452,333
Number of restricted stock units outstanding, Vested | shares (39,200)
Number of restricted stock units outstanding, Unvested ending balance | shares 1,413,133
Weighted-average grant date fair value, Unvested beginning balance | $ / shares $ 0
Weighted-average grant date fair value, Granted | $ / shares 8.00
Weighted-average grant date fair value, Vested | $ / shares 0
Weighted-average grant date fair value, Unvested ending balance | $ / shares $ 8.00