Shareholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Shares, Beginning Balance	1,553,360
Granted, Number of Shares	2,500
Exercised, Number of Shares	(28,387)
Forfeited, Number of Shares	(45,998)
Expired, Number of Shares	(2,751)
Number of Shares, Ending Balance	1,478,724
Vested and expected to vest, Number of Shares, Ending Balance	1,390,599
Exercisable, Number of Shares, Ending Balance	667,215
Weighted Average Exercise Price, Beginning Balance	$ 3.50
Granted, Weighted Average Exercise Price	$ 4.47
Exercised, Weighted Average Exercise Price	$ 2.97
Forfeited, Weighted Average Exercise Price	$ 3.20
Expired, Weighted Average Exercise Price	$ 3.13
Weighted Average Exercise Price, Ending Balance	$ 3.52
Vested and expected to vest, Weighted Average Exercise Price, Ending Balance	$ 3.51
Exercisable, Weighted Average Exercise Price, Ending Balance	$ 3.44
Weighted Average Remaining Contractual Life (in years)	6 years 8 months 19 days
Vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	6 years 7 months 2 days
Exercisable, Weighted Average Remaining Contractual Life (in years)	4 years 4 months 21 days
Aggregate Intrinsic Value	$ 1,896,962
Vested and expected to vest, Aggregate Intrinsic Value	1,797,179
Exercisable, Aggregate Intrinsic Value	$ 971,305