Stock-Based Compensation - Schedule of Share Based Compensation Stock Options Activity (Detail) (USD $)	9 Months Ended
	May 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning of period, Shares	1,824,916
Shares, Granted	120,000
Shares, Exercised	(49,000)
Shares, Cancelled	(189,964)
Options outstanding, end of period, Shares	1,705,952
Options exercisable, end of period, Shares	1,083,703
Weighted-Average Exercise Price, Options Outstanding beginning of period (in USD per share)	$ 10.94
Weighted-Average Exercise Price, Granted (in USD per share)	$ 8.49
Weighted-Average Exercise Price, Exercised (in USD per share)	$ 5.99
Weighted-Average Exercise Price, Cancelled (in USD per share)	$ 15.00
Weighted-Average Exercise Price, Options Outstanding end of period (in USD per share)	$ 10.46
Weighted-Average Exercise Price, Options Exercisable, end of period (in USD per share)	$ 12.93
Weighted Average Remaining Term, Outstanding, Ending Balance (in years)	3 years 9 months 15 days
Weighted Average Remaining Term, Options Exercisable (in years)	2 years 7 months 13 days
Aggregate Intrinsic value, Outstanding, Ending Balance	$ 5,374,500
Aggregate Intrinsic value, Options Exercisable	$ 1,838,900