Acquired Intangible Assets, net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization Of Intangible Assets Including Portion In Cost Of Revenue	$ 1,900	$ 1,900
Impairment of Intangible Assets, Finite-lived	$ 0	$ 0	$ 2,500
Discontinued Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			2,500
Discontinued Operations [Member] | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			2,400
Discontinued Operations [Member] | Developed technology
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			$ 100