Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Restricted Stock Activity (Detail)

v3.19.1
Stockholders' Equity - Restricted Stock Activity (Detail) - Restricted Stock [Member]
3 Months Ended
Mar. 31, 2019
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares, Unvested balance | shares 12,645,982
Number of shares, Restricted stock granted | shares 1,516,408
Number of shares, Restricted stock vested | shares (220,000)
Number of shares, Restricted stock units forfeited | shares (43,333)
Number of shares Restricted stock units vested | shares (33,750)
Number of shares, Unvested balance | shares 13,865,307
Weighted average grant price, Unvested balance | $ / shares $ 2.72
Weighted average grant price, Restricted stock granted | $ / shares 0.86
Weighted average grant price, Restricted stock vested | $ / shares 2.82
Weighted average grant price, Restricted stock units forfeited | $ / shares 4.56
Weighted average grant price, Restricted stock units vested | $ / shares 3.59
Weighted average grant price, Unvested balance | $ / shares $ 2.51