Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Jul. 24, 2013	Jun. 30, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	MAXWELL TECHNOLOGIES INC
Entity Central Index Key	0000319815
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Trading Symbol	mxwl
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	No
Entity Common Stock, Shares Outstanding		29,535,041
Entity Public Float			$ 179,494,759