Shareholders' Equity - Summary of Stock Option Activity under Plans (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Beginning Balance	1,539,618
Granted at fair value, Number of Shares	270,080
Exercised, Number of Shares	(3,000)
Forfeited, Number of Shares	(39,808)
Expired, Number of Shares	(150,127)
Number of Shares, Ending Balance	1,616,763
Vested and expected to vest, Number of Shares, Ending Balance	1,557,509
Exercisable, Number of Shares, Ending Balance	1,156,660
Weighted Average Exercise Price, Beginning Balance	$ 3.55
Granted at fair value, Weighted Average Exercise Price	$ 2.98
Exercised, Weighted Average Exercise Price	$ 2.67
Forfeited, Weighted Average Exercise Price	$ 3.50
Expired, Weighted Average Exercise Price	$ 4.24
Weighted Average Exercise Price, Ending Balance	$ 3.40
Vested and expected to vest, Weighted Average Exercise Price, Ending Balance	$ 3.40
Exercisable, Weighted Average Exercise Price, Ending Balance	$ 3.41
Weighted Average Remaining Contractual Life (in years), Ending Balance	4 years
Vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	3 years 10 months 28 days
Exercisable, Weighted Average Remaining Contractual Life (in years)	2 years 10 months 21 days
Aggregate Intrinsic Value	$ 257,000
Vested and expected to vest, Aggregate Intrinsic Value	257,000
Exercisable, Aggregate Intrinsic Value	$ 254,000