Restructuring Charges, Net - Additional Information (Detail) (USD $)	3 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Apr. 30, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 9,886,000	$ 3,682,000
Restructuring liability included in other long-term liabilities	800,000		700,000
Long-term restructuring liability, payment term	4 years
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	9,571,000
Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 315,000