Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v2.4.0.6
Income Taxes - Additional Information (Detail) (USD $)
12 Months Ended
Apr. 30, 2013
Apr. 30, 2010
Apr. 30, 2013
Internal Revenue Service (IRS)
Apr. 30, 2013
State and Local Jurisdiction
Apr. 30, 2013
Foreign Tax Authority
Schedule Of Income Taxes [Line Items]          
Net operating loss carryforward     $ 20,400,000 $ 13,200,000 $ 108,000,000
Net operating loss carryforward, beginning expiration     2028   2014
Foreign tax credit carryforwards     3,200,000    
Foreign tax credit carryforwards, beginning expiration     2023    
Net operating loss carryforward, beginning expiration       2014  
Deferred tax liability 900,000        
Undestributed earning of foreign subsidiaries 119,000,000        
Unrecognized tax benefits liability $ 2,023,000 $ 3,532,000