Stockholders' Equity - Summary of Stock Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Range One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 3.53
Range of Exercise Price, Upper Limit	$ 5.00
Number of Options Outstanding	1,886,679
Options outstanding, weighted average exercise price	$ 4.62
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	5 years 10 months 24 days
Number of Options Exercisable	1,739,833
Options Exercisable, Weighted Average Exercise Price	$ 4.63
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	5 years 9 months 18 days
Range Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 5.01
Range of Exercise Price, Upper Limit	$ 7.00
Number of Options Outstanding	528,221
Options outstanding, weighted average exercise price	$ 5.60
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	5 years 2 months 12 days
Number of Options Exercisable	526,521
Options Exercisable, Weighted Average Exercise Price	$ 5.60
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	5 years 1 month 6 days
Range Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 7.01
Range of Exercise Price, Upper Limit	$ 10.00
Number of Options Outstanding	649,381
Options outstanding, weighted average exercise price	$ 7.72
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years
Number of Options Exercisable	649,381
Options Exercisable, Weighted Average Exercise Price	$ 7.72
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	3 years
Range Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 10.01
Range of Exercise Price, Upper Limit	$ 15.00
Number of Options Outstanding	194,763
Options outstanding, weighted average exercise price	$ 10.31
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 4 months 24 days
Number of Options Exercisable	194,763
Options Exercisable, Weighted Average Exercise Price	$ 10.31
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	3 years 4 months 24 days
Range Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 15.01
Range of Exercise Price, Upper Limit	$ 29.83
Number of Options Outstanding	106,648
Options outstanding, weighted average exercise price	$ 18.69
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 months 24 days
Number of Options Exercisable	106,648
Options Exercisable, Weighted Average Exercise Price	$ 18.69
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4 months 24 days
Range Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	$ 3.53
Range of Exercise Price, Upper Limit	$ 29.83
Number of Options Outstanding	3,365,692
Options outstanding, weighted average exercise price	$ 6.15
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 10 months 24 days
Number of Options Exercisable	3,217,146
Options Exercisable, Weighted Average Exercise Price	$ 6.22
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4 years 9 months 18 days