Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Stock Options, Stock Purchase Plan and Warrants - Summary of Information about our Options Outstanding (Detail)

v3.8.0.1
Stock Options, Stock Purchase Plan and Warrants - Summary of Information about our Options Outstanding (Detail)
12 Months Ended
Dec. 31, 2017
$ / shares
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Outstanding number of options | shares 6,342,526
Weighted average remaining contractual life outstanding 3 years 2 months 27 days
Outstanding average exercise price $ 6.52
Exercisable, number of options | shares 2,103,342
Weighted average remaining contractual life exercisable 2 years 5 months 5 days
Exercisable, average exercise Price $ 5.50
Range One [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 1.47
Price Range, Maximum $ 4.00
Outstanding number of options | shares 296,001
Weighted average remaining contractual life outstanding 11 months 19 days
Outstanding average exercise price $ 3.53
Exercisable, number of options | shares 273,501
Weighted average remaining contractual life exercisable 11 months 12 days
Exercisable, average exercise Price $ 3.52
Range Two [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 4.01
Price Range, Maximum $ 5.00
Outstanding number of options | shares 1,600,334
Weighted average remaining contractual life outstanding 2 years 2 months 23 days
Outstanding average exercise price $ 4.76
Exercisable, number of options | shares 1,044,500
Weighted average remaining contractual life exercisable 2 years 2 months 12 days
Exercisable, average exercise Price $ 4.75
Range Three [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 5.01
Price Range, Maximum $ 7.00
Outstanding number of options | shares 513,832
Weighted average remaining contractual life outstanding 2 years 11 months 19 days
Outstanding average exercise price $ 6.59
Exercisable, number of options | shares 158,257
Weighted average remaining contractual life exercisable 2 years 10 months 14 days
Exercisable, average exercise Price $ 6.49
Range Four [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 7.01
Price Range, Maximum $ 7.50
Outstanding number of options | shares 1,901,528
Weighted average remaining contractual life outstanding 3 years 5 months 27 days
Outstanding average exercise price $ 7.17
Exercisable, number of options | shares 507,511
Weighted average remaining contractual life exercisable 3 years 3 months 19 days
Exercisable, average exercise Price $ 7.15
Range Five [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 7.51
Price Range, Maximum $ 8.00
Outstanding number of options | shares 1,644,999
Weighted average remaining contractual life outstanding 4 years 3 months 4 days
Outstanding average exercise price $ 7.55
Exercisable, number of options | shares 37,500
Weighted average remaining contractual life exercisable 2 years 11 months 23 days
Exercisable, average exercise Price $ 7.86
Range Six [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Price Range, Minimum 8.01
Price Range, Maximum $ 9.47
Outstanding number of options | shares 385,832
Weighted average remaining contractual life outstanding 3 years 11 months 4 days
Outstanding average exercise price $ 8.47
Exercisable, number of options | shares 82,073
Weighted average remaining contractual life exercisable 3 years 7 months 24 days
Exercisable, average exercise Price $ 8.39