Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Stockholders Equity Note [Abstract]
Number of Shares Outstanding, Beginning	7,697,892
Number of Shares Granted	17,500
Number of Shares Exercised	(570,178)	(78,417)
Number of Shares canceled/Forfeited	(7,500)
Number of Shares Outstanding, Ending	7,137,714
Number of Shares Exercisable, Ending	5,834,951
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 1.89
Weighted Average Exercise Price Granted	$ 4.45
Weighted Average Exercise Price Exercised	$ 1.21	$ 0.64
Weighted Average Exercise Price Cancelled/Forfeited	$ 4.45
Weighted Average Exercise Price Outstanding, Ending Balance	$ 1.95
Weighted Average Exercise Price Exercisable, Ending Balance	$ 1.56
Weighted Average Remaining Contractual Term Outstanding, Ending	6 years 6 months
Weighted Average Remaining Contractual Term Exercisable, Ending	5 years 10 months 24 days
Aggregate Intrinsic Value, Exercised	$ 2,057,025
Aggregate Intrinsic Value Outstanding, Ending	11,756,129
Aggregate Intrinsic Value Exercisable, Ending	$ 11,496,000