Restructuring Charges - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 40	$ 327
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 300
Restructuring charges, incurred to date	2,700
2017 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred to date	$ 1,200