Restructuring Charges - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,108	$ 0	$ 767	$ 327	$ 1,575	$ 0	$ 0	$ 0	$ 2,202	$ 1,575	$ 0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									1,567	1,029
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									635	546
2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									1,100	$ 1,600
Restructuring and Related Cost, Cost Incurred to Date	$ 2,700								2,700
2017 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									$ 1,100