Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)
6 Months Ended
Jun. 30, 2017
$ / shares
shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Number of Options, Options outstanding, Beginning balance | shares 4,691,746
Number of Options, Granted | shares 1,502,500
Number of Options, Expired | shares (93,300)
Number of Options, Forfeited | shares (63,963)
Number of Options, Options outstanding, Ending balance | shares 6,036,984
Number of Options, Vested and exercisable, Ending Balance | shares 4,045,365
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares $ 4.62
Weighted Average Exercise Price, Granted | $ / shares 1.73
Weighted Average Exercise Price, Expired | $ / shares 4.78
Weighted Average Exercise Price, Forfeited | $ / shares 2.81
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares 3.91
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares $ 4.61
Weighted Average Remaining Contractual Life (in years), Options outstanding 6 years 2 months 30 days
Weighted Average Remaining Contractual Life (in years), Vested and exercisable 4 years 10 months 28 days