Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Restricted Stock Activity (Detail)

v3.10.0.1
Stockholders' Equity - Restricted Stock Activity (Detail) - Restricted Stock [Member]
9 Months Ended
Sep. 30, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares, Unvested balance | shares 11,874,034
Number of shares, Restricted stock granted | shares 1,392,856
Number of shares, Restricted stock vested | shares (213,333)
Number of shares, Restricted stock units granted | shares 430,000
Number of shares, Restricted stock units forfeited | shares (426,978)
Number of shares, Restricted stock units vested | shares (516,732)
Number of shares, Unvested balance | shares 12,539,847
Weighted average grant price, Unvested balance | $ / shares $ 2.63
Weighted average grant price, Restricted stock granted | $ / shares 3.99
Weighted average grant price, Restricted stock vested | $ / shares 2.76
Weighted average grant price, Restricted stock units granted | $ / shares 4.03
Weighted average grant price, Restricted stock units forfeited | $ / shares 4.05
Weighted average grant price, Restricted stock units vested | $ / shares 3.56
Weighted average grant price, Unvested balance | $ / shares $ 2.74