Stockholders' Equity - Summary of Information about Employee and Director Stock Options Outstanding and Exercisable (Detail) (USD $)	0 Months Ended
	Jan. 31, 2015	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Number outstanding	1,626,421	1,626,421
Options Outstanding, Weighted average remaining contractual terms (years)	4 years 8 months 19 days
Options Outstanding, Weighted average exercise price	$ 7.77	$ 7.77
Options Exercisable, Number Exercisable	1,108,115	1,108,115
Options Exercisable, Weighted average exercise price	$ 8.02	$ 8.02
Exercise Price Range One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 6.74
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 6.74
Options Outstanding, Number outstanding	224,421	224,421
Options Outstanding, Weighted average remaining contractual terms (years)	3 years 11 months 16 days
Options Outstanding, Weighted average exercise price	$ 6.74	$ 6.74
Options Exercisable, Number Exercisable	207,781	207,781
Options Exercisable, Weighted average exercise price	$ 6.74	$ 6.74
Exercise Price Range Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 7.00
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 7.48
Options Outstanding, Number outstanding	501,000	501,000
Options Outstanding, Weighted average remaining contractual terms (years)	6 years 1 month 6 days
Options Outstanding, Weighted average exercise price	$ 7.23	$ 7.23
Options Exercisable, Number Exercisable	1,000	1,000
Options Exercisable, Weighted average exercise price	$ 7.00	$ 7.00
Exercise Price Range Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 7.49
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 7.49
Options Outstanding, Number outstanding	1,000	1,000
Options Outstanding, Weighted average remaining contractual terms (years)	4 months 6 days
Options Outstanding, Weighted average exercise price	$ 7.49	$ 7.49
Options Exercisable, Number Exercisable	1,000	1,000
Options Exercisable, Weighted average exercise price	$ 7.49	$ 7.49
Exercise Price Range Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 7.72
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 7.72
Options Outstanding, Number outstanding	4,500	4,500
Options Outstanding, Weighted average remaining contractual terms (years)	5 months 9 days
Options Outstanding, Weighted average exercise price	$ 7.72	$ 7.72
Options Exercisable, Number Exercisable	4,500	4,500
Options Exercisable, Weighted average exercise price	$ 7.72	$ 7.72
Exercise Price Range Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 8.15
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 8.15
Options Outstanding, Number outstanding	5,000	5,000
Options Outstanding, Weighted average remaining contractual terms (years)	4 years 5 months 1 day
Options Outstanding, Weighted average exercise price	$ 8.15	$ 8.15
Options Exercisable, Number Exercisable	3,334	3,334
Options Exercisable, Weighted average exercise price	$ 8.15	$ 8.15
Exercise Price Range Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 8.22
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 8.22
Options Outstanding, Number outstanding	875,000	875,000
Options Outstanding, Weighted average remaining contractual terms (years)	4 years 2 months 27 days
Options Outstanding, Weighted average exercise price	$ 8.22	$ 8.22
Options Exercisable, Number Exercisable	875,000	875,000
Options Exercisable, Weighted average exercise price	$ 8.22	$ 8.22
Exercise Price Range Seven [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 11.56
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 11.56
Options Outstanding, Number outstanding	2,000	2,000
Options Outstanding, Weighted average remaining contractual terms (years)	2 months 9 days
Options Outstanding, Weighted average exercise price	$ 11.56	$ 11.56
Options Exercisable, Number Exercisable	2,000	2,000
Options Exercisable, Weighted average exercise price	$ 11.56	$ 11.56
Exercise Price Range Eight [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 12.95
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 12.95
Options Outstanding, Number outstanding	2,000	2,000
Options Outstanding, Weighted average remaining contractual terms (years)	2 months 1 day
Options Outstanding, Weighted average exercise price	$ 12.95	$ 12.95
Options Exercisable, Number Exercisable	2,000	2,000
Options Exercisable, Weighted average exercise price	$ 12.95	$ 12.95
Exercise Price Range Nine [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 13.66
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 13.66
Options Outstanding, Number outstanding	6,500	6,500
Options Outstanding, Weighted average remaining contractual terms (years)	1 month 2 days
Options Outstanding, Weighted average exercise price	$ 13.66	$ 13.66
Options Exercisable, Number Exercisable	6,500	6,500
Options Exercisable, Weighted average exercise price	$ 13.66	$ 13.66
Exercise Price Range Ten [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 16.56
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 16.56
Options Outstanding, Number outstanding	5,000	5,000
Options Outstanding, Weighted average remaining contractual terms (years)	4 days
Options Outstanding, Weighted average exercise price	$ 16.56	$ 16.56
Options Exercisable, Number Exercisable	5,000	5,000
Options Exercisable, Weighted average exercise price	$ 16.56	$ 16.56