Document and Entity Information - shares	3 Months Ended
	Jun. 30, 2018	Aug. 03, 2018
Document And Entity Information [Abstract]
Entity Common Stock, Shares Outstanding		34,137,898
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Entity Registrant Name	ELECTRO SCIENTIFIC INDUSTRIES INC
Entity Central Index Key	0000726514
Current Fiscal Year End Date	--03-31
Entity Well-know Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer