Document and Entity Information - shares	6 Months Ended
	Oct. 01, 2016	Nov. 04, 2016
Document And Entity Information [Abstract]
Entity Common Stock, Shares Outstanding		32,464,117
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 01, 2016
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
Entity Registrant Name	ELECTRO SCIENTIFIC INDUSTRIES INC
Entity Central Index Key	0000726514
Current Fiscal Year End Date	--04-02
Entity Well-know Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer