Document And Entity Information - shares	3 Months Ended
	Jun. 30, 2017	Jul. 27, 2017
Document Information [Line Items]
Entity Registrant Name	IXYS CORP /DE/
Entity Central Index Key	0000945699
Trading Symbol	ixys
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		32,603,143
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Amendment Flag	false