Basis of Financial Statement Presentation (Details) Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended								9 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012	Dec. 31, 2013 USD ($)	Dec. 31, 2012	Mar. 31, 2013 USD ($)	Aug. 28, 2012 USD ($)	Aug. 31, 2006 USD ($)	Aug. 31, 2006 EUR (€)	Dec. 31, 2013 Carrying Value USD ($)	Mar. 31, 2013 Carrying Value USD ($)	Dec. 31, 2013 Recurring USD ($)	Dec. 31, 2013 Recurring Fair Value USD ($)	Mar. 31, 2013 Recurring Fair Value USD ($)	Dec. 31, 2013 Recurring Level 1 Fair Value USD ($)	Mar. 31, 2013 Recurring Level 1 Fair Value USD ($)	Dec. 31, 2013 Recurring Level 2 Fair Value USD ($)	Mar. 31, 2013 Recurring Level 2 Fair Value USD ($)	Dec. 31, 2013 Recurring Level 3 Fair Value USD ($)	Mar. 31, 2013 Recurring Level 3 Fair Value USD ($)
Restricted Cash
Prepayment received from an OEM						$ 24,000,000
Amount of prepayment utilized for purchase of manufacturing equipment			12,300,000
Prepayment received from an OEM classified as restricted cash	11,700,000		11,700,000
Guarantee issued by the European bank in conjunction with the establishment of a VAT registration in The Netherlands							2,100,000	1,500,000
Deposits pledged to European bank							2,300,000	1,700,000
Fair Value Measurement
Money markets									504,000	29,984,000		504,000	29,984,000	504,000	29,984,000
Total debt									401,895,000	383,500,000		398,982,000	393,928,000	358,550,000	369,200,000	40,432,000	24,728,000
NEC TOKIN options, net									1,823,000	489,000		1,823,000	489,000					1,823,000	489,000
NEC TOKIN option valuation activity using significant unobservable inputs (Level 3)
Balance at the beginning of the period											489,000
Increase in value of NEC TOKIN options			1,334,000								1,334,000
Balance at the end of the period											1,823,000
Components of inventories
Raw materials and supplies	94,282,000		94,282,000		84,149,000
Work in process	61,191,000		61,191,000		64,499,000
Finished goods	71,787,000		71,787,000		68,704,000
Inventory, gross	227,260,000		227,260,000		217,352,000
Inventory reserves	(26,407,000)		(26,407,000)		(18,464,000)
Inventories, net	200,853,000		200,853,000		198,888,000
Reserve for inventory held by a third party			$ 3,900,000
Warrant
Number of shares subject to a warrant held by K Equity, LLC	8.4		8.4		8.4
Revenue Recognition
Period of product warranty			1 year
Warranty costs as a percentage of net sales, maximum	1.50%	1.50%	1.50%	1.50%