Fair Value of Warrants Using Black-Scholes Option Pricing Model (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Market price of common stock:	$ 6.44
Exercise price:	$ 3.50
Remaining contractual life (years):	1 year 8 months 23 days
Dividend yield:
Expected volatility:	39.43%
Risk-free interest rate:	0.21%
Fair Value	$ 253,000	$ 615,000
Series A and B Warrants
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Market price of common stock:	$ 3.56	$ 4.76
Exercise price:	$ 3.50	$ 3.50
Remaining contractual life (years):	1 year 29 days	1 year 9 months 29 days
Dividend yield:
Expected volatility:	60.52%	39.58%
Risk-free interest rate:	0.16%	0.22%
Fair Value	229,000	586,000
Underwriter Warrants
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Market price of common stock:	$ 3.56	$ 4.76
Exercise price:	$ 4.80	$ 4.80
Remaining contractual life (years):	2 years 11 months 5 days	2 years 8 months 5 days
Dividend yield:
Expected volatility:	60.63%	36.39%
Risk-free interest rate:	0.22%	0.32%
Fair Value	$ 24,000	$ 29,000