Stock Options - Options Granted to Officers of Company Outside (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Outstanding, Beginning Balance	8,648,268
Shares, Granted	1,395,000
Shares, Forfeited	(158,871)
Shares, Exercised	(493,497)
Shares Outstanding, Ending Balance	9,390,900
Shares, Vested	4,185,972
Weighted Average Exercise Price, Beginning Balance	$ 1.29
Weighted Average Exercise Price, Granted	$ 2.71
Weighted Average Exercise Price, Forfeited	$ 1.52
Weighted Average Exercise Price, Exercised	$ 0.74
Weighted Average Exercise Price, Ending Balance	$ 1.53
Weighted Average Exercise Price, Vested	$ 0.90
Weighted Average Remaining Contractual Term in Years	7 years 7 months 24 days
Weighted Average Exercise Price Shares, Vested	6 years 1 month 17 days
Aggregate Intrinsic Value	$ 24,486,331
Aggregate Intrinsic Value Shares, Vested	$ 13,531,387