Stock Options - Summary of Option Activity and Changes (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Outstanding, Beginning Balance	8,648,268
Shares, Granted	1,395,000
Shares, Forfeited	(2,065,294)
Shares, Exercised	(574,120)
Shares Outstanding, Ending Balance	7,403,854
Shares, Vested	4,252,351
Weighted Average Exercise Price, Beginning Balance	$ 1.29
Weighted Average Exercise Price, Granted	$ 2.71
Weighted Average Exercise Price, Forfeited	$ 1.73
Weighted Average Exercise Price, Exercised	$ 0.79
Weighted Average Exercise Price, Ending Balance	$ 1.47
Weighted Average Exercise Price, Vested	$ 0.90
Weighted Average Remaining Contractual Term in Years, Outstanding	7 years 26 days
Weighted Average Remaining Contractual Term in Years, Vested	5 years 9 months 26 days
Aggregate Intrinsic Value	$ 3,795,072
Aggregate Intrinsic Value, Vested	$ 3,558,913