Document And Entity Information - shares	6 Months Ended
	Sep. 30, 2016	Oct. 27, 2016
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)		31,536,752
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
Amendment Flag	false