Restructuring Charges - Accrued Liability Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Restructuring Cost and Reserve [Line Items]
Balance at April 30, 2015				$ 0					$ 0
Restructuring charges	$ 1,575	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	1,575	$ 0	$ 0
Payments									(532)
Balance at April 30, 2016	1,043				$ 0				1,043	$ 0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									1,029
Payments									(532)
Balance at April 30, 2016	497								497
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges									546
Payments									0
Balance at April 30, 2016	$ 546								$ 546