Quarterly report pursuant to Section 13 or 15(d)

Additional Information Pertaining to Stock Options (Detail)

v3.3.1.900
Additional Information Pertaining to Stock Options (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Oct. 31, 2015
Oct. 31, 2014
Oct. 31, 2015
Oct. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total fair value of stock options vested   $ 10 $ 96 $ 334
Total intrinsic value of stock options exercised $ 198 $ 332 $ 1,558 $ 1,371