Summary of Options Outstanding and Exercisable (Detail) (Stock Option, USD $)	12 Months Ended
	Dec. 31, 2013
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	6,032,188
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	5 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.90
Options Exercisable, Number Exercisable	4,848,298
Options Exercisable, Weighted Average Exercise Price	$ 1.05
Exercise Price 0.30
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	56,771
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	4 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.30
Options Exercisable, Number Exercisable	56,771
Options Exercisable, Weighted Average Exercise Price	$ 0.30
Exercise Price 0.33
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	125,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	7 years 6 months
Options Outstanding, Weighted Average Exercise Price	$ 0.33
Options Exercisable, Number Exercisable	89,583
Options Exercisable, Weighted Average Exercise Price	$ 0.33
Exercise Price 0.35
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	25,000
Options Exercisable, Weighted Average Exercise Price	$ 0.35
Exercise Price 0.39
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	25,000
Options Exercisable, Weighted Average Exercise Price	$ 0.39
Exercise Price 0.46
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	2,500,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	9 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 0.46
Options Exercisable, Number Exercisable	1,423,611
Options Exercisable, Weighted Average Exercise Price	$ 0.46
Exercise Price 0.53
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	20,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	7 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price	$ 0.53
Options Exercisable, Number Exercisable	13,333
Options Exercisable, Weighted Average Exercise Price	$ 0.53
Exercise Price 0.54
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	25,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	9 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.54
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 0
Exercise Price 0.90
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	730,417
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	4 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 0.90
Options Exercisable, Number Exercisable	715,000
Options Exercisable, Weighted Average Exercise Price	$ 0.90
Exercise Price 1.40
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	2,500,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	4 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 1.40
Options Exercisable, Number Exercisable	2,500,000
Options Exercisable, Weighted Average Exercise Price	$ 1.40
Exercise Price 1.95
Share Based Compensation Plans [Line Items]
Options Outstanding, Number Outstanding	25,000
Options Outstanding, Weighted Average Remaining Remaining Contractual Life (Years)	9 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price	$ 1.95
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted Average Exercise Price	$ 1.95