Borrowings (Short-term borrowings) (Details)	Dec. 20, 2005 USD ($)	Dec. 31, 2012 Maxwell SA short-term loan [Member] USD ($)	Dec. 31, 2012 Maxwell SA short-term loan [Member] CHF	Dec. 31, 2011 Maxwell SA short-term loan [Member]	Dec. 31, 2012 Maxwell SA credit agreement [Member] Maxwell SA Line of Credit Agreement, Annual Renewal, 2.35% Interest [Member] USD ($)	Dec. 31, 2012 Maxwell SA credit agreement [Member] Maxwell SA Line of Credit Agreement, Annual Renewal, 2.35% Interest [Member] CHF	Dec. 31, 2011 Maxwell SA credit agreement [Member] Maxwell SA Line of Credit Agreement, Annual Renewal, 2.35% Interest [Member]	Dec. 31, 2012 Maxwell SA credit agreement [Member] Maxwell SA Line of Credit Agreement, No Contractual Renewal [Member] USD ($)	Dec. 31, 2012 Maxwell SA credit agreement [Member] Maxwell SA Line of Credit Agreement, No Contractual Renewal [Member] CHF
Short-term Debt [Line Items]
Short-term loan agreement, amount	$ 25,000,000	$ 3,300,000	3,000,000
Credit agreement maximum borrowing					$ 2,200,000	2,000,000		$ 1,100,000	1,000,000
Stated interest rate		2.20%	2.20%	2.20%	2.35%	2.35%	2.35%