Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012
Income Tax Disclosure [Abstract]
Effective tax rate	40.00%		37.00%
Write-off of deferred tax assets related to expired stock option awards			$ 300,000
Tax Credit Recorded During Period Related to Research and Development	150,000
Percentage of effective tax rate related to tax credit for research and development			2.00%
Income tax expense on pre-tax loss	1,365,000	3,875,000	2,875,000	5,041,000
Pre-tax loss	3,423,000	(1,577,000)	7,831,000	(159,000)
Difference between the recorded tax expense and expected tax expense				100,000
Non-deductible dividends, accretion of discount and amortization of issuance costs on the redemption of the Series A Preferred Stock				8,600,000
Valuation allowance		1,800,000		1,800,000
Small ethanol producer tax credit carryforward expiration date			Aug. 31, 2014
Net deferred tax assets	11,100,000		11,100,000
Liability decrease relating to unrecognized tax benefits, penalties	121,000		58,000
Liability increase relating to unrecognized tax benefits, interest			1,000,000
Accrued interest and penalties included in long-term tax liability	$ 200,000		$ 200,000