Document and Entity Information (USD $)	12 Months Ended
	Mar. 31, 2012	May 25, 2012	Sep. 30, 2011
Document And Entity Information [Abstract]
Entity Registrant Name	IXYS CORP /DE/
Entity Central Index Key	0000945699
Document Type	10-K
Document Period End Date	Mar. 31, 2012
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 267,063,363
Entity Common Stock Shares Outstanding		31,323,538
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY