Restructuring Charges, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016	Apr. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3,801	$ 30,577	$ 28,321	$ 30,577
Restructuring liability included in other long-term liabilities	5,000		5,000		$ 600
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges		29,900	11,472	29,900
Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3,801	$ 700	$ 16,849	$ 700