Business Combinations - Purchase Price (Detail) - USD ($) $ in Thousands	Apr. 15, 2014	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Business Acquisition [Line Items]
Goodwill		$ 139,155	$ 139,155	$ 132,831
FeedMagnet
Business Acquisition [Line Items]
Cash and cash equivalents	$ 383
Accounts receivable	695
Prepaid expenses and other current assets	19
Total identified intangibles	3,800
Goodwill	6,324
Total assets acquired	11,221
Accounts payable	(80)
Accrued expenses and other current liabilities	(187)
Deferred revenue	(234)
Deferred tax liability	(1,391)
Total liabilities assumed	(1,892)
Net assets acquired	9,329
Cash	9,329
Total consideration	9,329
Developed Technology | FeedMagnet
Business Acquisition [Line Items]
Intangible assets subject to amortization	3,265
Customer Relationships | FeedMagnet
Business Acquisition [Line Items]
Intangible assets subject to amortization	$ 535