Summary of Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	3,482,188
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	5 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 1.22
Options Exercisable, Number Exercisable	181,771
Options Exercisable, Weighted Average Exercise Price	$ 0.32
Exercise Price Zero Point Three | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	56,771
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	5 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.3
Options Exercisable, Number Exercisable	56,771
Options Exercisable, Weighted Average Exercise Price	$ 0.3
Exercise Price Zero Point Three Three | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	125,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	8 years 6 months
Options Outstanding, Weighted Average Exercise Price	$ 0.33
Options Exercisable, Number Exercisable	125,000
Options Exercisable, Weighted Average Exercise Price	$ 0.33
Exercise Price Zero Point Three Five | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	25,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	8 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.35
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price Zero Point Three Nine | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	25,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	8 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.39
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price Zero Point Five Three | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	20,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	8 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price	$ 0.53
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price Zero Point Nine Zero | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	730,417
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	5 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.9
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price One Point Four Zero | Stock Options
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	2,500,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	5 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 1.4
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0