Quarterly report pursuant to Section 13 or 15(d)

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

v3.10.0.1
Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)
9 Months Ended
Sep. 30, 2018
USD ($)
$ / shares
shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Number of Options, Options outstanding, Beginning balance | shares 6,200,151
Number of Options, Granted | shares 2,280,000
Number of Options, Exercised | shares 0
Number of Options, Expired | shares (865,606)
Number of Options, Forfeited | shares (366,347)
Number of Options, Options outstanding, Ending balance | shares 7,248,198
Number of Options, Vested and exercisable, Ending Balance | shares 4,714,393
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares $ 3.81
Weighted Average Exercise Price, Granted | $ / shares 1.45
Weighted Average Exercise Price, Exercised | $ / shares 0
Weighted Average Exercise Price, Expired | $ / shares 3.93
Weighted Average Exercise Price, Forfeited | $ / shares 1.84
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares 3.15
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares $ 3.88
Weighted Average Remaining Contractual Life (in years), Options outstanding 6 years 11 months 1 day
Weighted Average Remaining Contractual Life (in years), Vested and exercisable 5 years 10 months 20 days
Aggregate Intrinsic value, Options outstanding | $ $ 1,987,550
Aggregate Intrinsic value, Vested and exercisable | $ $ 762,306