Accounting for Stock-Based Compensation - Summary of Stock Options Outstanding and Exercisable (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	3,010,980
Weighted Average remaining Contractual Life	1 year 3 months 18 days
Weighted Average Exercise Price	$ 1.51
Range of Exercise Prices from $1.15 to $1.36 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Minimum Range of Exercise Price	$ 1.15
Maximum Range of Exercise Price	$ 1.36
Number Outstanding	2,287,500
Weighted Average remaining Contractual Life	10 months 24 days
Weighted Average Exercise Price	$ 1.15
Range of Exercise Prices from $2.00 to $3.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Minimum Range of Exercise Price	$ 2.00
Maximum Range of Exercise Price	$ 3.00
Number Outstanding	539,980
Weighted Average remaining Contractual Life	2 years 2 months 12 days
Weighted Average Exercise Price	$ 2.33
Range of Exercise Prices from $3.10 to $4.65 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Minimum Range of Exercise Price	$ 3.10
Maximum Range of Exercise Price	$ 4.65
Number Outstanding	155,000
Weighted Average remaining Contractual Life	4 years 3 months 18 days
Weighted Average Exercise Price	$ 3.17
Range of Exercise Prices from $4.99 to $6.96 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Minimum Range of Exercise Price	$ 4.99
Maximum Range of Exercise Price	$ 6.96
Number Outstanding	20,500
Weighted Average remaining Contractual Life	9 months 18 days
Weighted Average Exercise Price	$ 5.66