Business Combinations - Purchase Price (Details) - USD ($) $ in Thousands			12 Months Ended
	Apr. 15, 2014	Jun. 12, 2012	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Business Acquisition [Line Items]
Goodwill			$ 139,155	$ 139,155
Cash			$ 0	$ 0	$ 9,616
Total consideration		$ 150,800
FeedMagnet [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	$ 383
Accounts receivable	695
Prepaid expenses and other current assets	19
Developed technology (3 year useful life)	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 [Member]
Business Acquisition [Line Items]
Developed technology (3 year useful life)	3,265
Customer relationships | FeedMagnet [Member]
Business Acquisition [Line Items]
Developed technology (3 year useful life)	$ 535