Quarterly report pursuant to Section 13 or 15(d)

Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)

v3.19.2
Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)
6 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Number of Options, Options outstanding, Beginning balance | shares 7,187,885
Number of Options, Granted | shares 5,505,000
Number of Options, Exercised | shares 0
Number of Options, Expired | shares (192,266)
Number of Options, Forfeited | shares (135,625)
Number of Options, Options outstanding, Ending balance | shares 12,364,994
Number of Options, Vested and exercisable, Ending Balance | shares 5,540,325
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares $ 3.17
Weighted Average Exercise Price, Granted | $ / shares 0.40
Weighted Average Exercise Price, Exercised | $ / shares 0
Weighted Average Exercise Price, Expired | $ / shares 2.92
Weighted Average Exercise Price, Forfeited | $ / shares 1.22
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares 1.96
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares $ 3.49
Weighted Average Remaining Contractual Life (in years), Options outstanding 7 years 8 months 1 day
Weighted Average Remaining Contractual Life (in years), Vested and exercisable 5 years 7 months 17 days
Aggregate Intrinsic value, Options outstanding | $ $ 585,100
Aggregate Intrinsic value, Vested and exercisable | $ $ 29,138