Assumptions Used In Binomial Valuation Model and Black-Scholes Valuation Model (Detail)	Dec. 31, 2009	Sep. 30, 2012 Monte Carlo Option Pricing Model [Member]	Sep. 30, 2011 Black Scholes Option Pricing Model [Member]	Sep. 30, 2012 Minimum [Member] Monte Carlo Option Pricing Model [Member]	Sep. 30, 2011 Minimum [Member] Black Scholes Option Pricing Model [Member]	Sep. 30, 2011 Maximum [Member] Black Scholes Option Pricing Model [Member]
Class of Warrant or Right [Line Items]
Risk-free interest rate	2.14%			0.23%	0.08%	0.47%
Expected volatility	105.00%			0.70%	48.90%	95.50%
Expected dividend yield	0.00%	0.00%	0.00%
Expected life in years	5			2.19	0.67	3.18