Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Restricted Stock Activity (Detail)

v3.8.0.1
Stockholders' Equity - Restricted Stock Activity (Detail) - Restricted Stock [Member]
3 Months Ended
Mar. 31, 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 (213,334)
Number of shares, Restricted stock units granted | shares 230,000
Number of shares, Restricted stock units forfeited | shares (42,417)
Number of shares, Restricted stock units vested | shares (64,750)
Number of shares, Unvested balance | shares 13,176,389
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 4.98
Weighted average grant price, Restricted stock units forfeited | $ / shares 3.52
Weighted average grant price, Restricted stock units vested | $ / shares 3.49
Weighted average grant price, Unvested balance | $ / shares $ 2.81