Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012	Apr. 30, 2007
Stock Options [Member]
Limited Partners' Capital Account [Line Items]
Expiration period of options granted					10 years
Stock-based compensation expense	$ 88	$ 95	$ 203	$ 162
Unrecognized stock-based compensation expense	596		596
Unrecognized stock-based compensation expense, weighted average period			2 years
Performance Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Awarded certain employees			0
Unrecognized stock-based compensation expense	0		0
Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	475	519	966	1,092
Restricted Stock and Restricted Stock Unit [Member]
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period			2 years
Unrecognized stock-based compensation expense	2,766		2,766
Performance Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period			1 year 1 month 6 days
Unrecognized stock-based compensation expense	3,982		3,982
Employee Stock Purchase Plan [Member]
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 15	$ 17	$ 39	$ 52
Minimum [Member] | Stock Options [Member]
Limited Partners' Capital Account [Line Items]
Vesting period from date of grant			1 year
Maximum [Member] | Stock Options [Member]
Limited Partners' Capital Account [Line Items]
Vesting period from date of grant			4 years
Maximum [Member] | Restricted Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Vesting period from date of grant			3 years
Class A Common Stock [Member] | 2006 Stock Incentive Plan [Member]
Limited Partners' Capital Account [Line Items]
Common stock, issued shares					2,475
Number of shares available for future grant	1,104		1,104