Restructuring Charges (Narrative) (Details) $ in Thousands		3 Months Ended	9 Months Ended
Jun. 01, 2018 employee	Jan. 31, 2019 USD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)
Restructuring and Related Activities [Abstract]
Number of employees reduced in force \| employee	54
Restructuring charges, net		$ 26	$ 2,061	$ 0
Restructuring reserve		$ 698	$ 698		$ 0

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration