Movements of Options Issued and Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Number of Underlying Shares
Numberof underlying shares, Outstanding at begning of the period	715,000		115,000		65,000
Granted	60,000		600,000		60,000
Exercised	0		0		0
Expired	0		0		0
Forfeited	(60,000)		0		(10,000)
Numberof underlying shares, Outstanding at end of the period	715,000		715,000		115,000		65,000
Exercisable at December 31,2012	415,000
Weighted Average Exercise Price Per Share
Weighted- Average ExercisePrice PerShare, Outstanding at begining of the period	$ 5.16		$ 6.74		$ 4.06
Granted	$ 5.63		$ 4.85		$ 8.49
Forfeited	$ 4.50				$ 2.20
Weighted- Average ExercisePrice PerShare, Outstanding at end of the period	$ 5.25		$ 5.16		$ 6.74		$ 4.06
Exercisable at December 31,2012	$ 5.71
Aggregate Intrinsic Value
Aggregate Intrinsic Value(1), Outstanding at begning of the period	$ 213,300	[1]	$ 517,450	[1]	$ 415,450	[1]
Aggregate Intrinsic Value(1), Outstanding at end of the period	65,700	[1]	213,300	[1]	517,450	[1]	415,450	[1]
Exercisable at December 31,2012	$ 65,700	[1]
Weighted Average Contractual Life Remaining in Years
Weighted- Average Contractual Life Remaining in Years Outstanding	8 years 5 months 19 days		9 years 5 months 5 days		9 years		9 years 2 months 12 days
Granted	10 years		10 years		10 years
Weighted-Average ContractualLife Remainingin Years, Exercisable at December 31, 2012	8 years 2 months 5 days

[1] The intrinsic value of the stock options at December 31, 2012, 2011 and 2010 is the amount by which the market value of the Company's common stock of $4.39, $4.76 and $11.24 as of December 31, 2012, 2011 and 2010 exceeds the exercise price of the option.