Document And Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2016	May. 23, 2016	Sep. 30, 2015
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)		31,383,024
Entity Public Float			$ 274,130,959
Document Type	10-K
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Amendment Flag	false