Basis of Financial Statement Presentation (Details)	3 Months Ended					6 Months Ended						6 Months Ended
	Sep. 30, 2014 USD ($)	Sep. 30, 2014 EUR (€)	Jun. 30, 2014 USD ($)	Sep. 30, 2013	Jun. 30, 2013 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Mar. 31, 2014 USD ($)	Aug. 28, 2012 USD ($)	Sep. 30, 2014 Carrying Value USD ($)	Mar. 31, 2014 Carrying Value USD ($)	Sep. 30, 2014 Recurring USD ($)	Sep. 30, 2014 Recurring Fair Value USD ($)	Mar. 31, 2014 Recurring Fair Value USD ($)	Sep. 30, 2014 Recurring Level 1 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 1 Fair Value USD ($)	Sep. 30, 2014 Recurring Level 2 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 2 Fair Value USD ($)	Sep. 30, 2014 Recurring Level 3 Fair Value USD ($)	Mar. 31, 2014 Recurring Level 3 Fair Value USD ($)	Sep. 30, 2014 Interest-bearing deposits USD ($)	Sep. 30, 2014 Interest-bearing deposits EUR (€)
Restricted Cash
Prepayment received from an OEM									$ 24,000,000
Amount of prepayment utilized for purchase of manufacturing equipment						13,100,000
Prepayment received from an OEM classified as restricted cash	10,900,000					10,900,000
Guarantee issued by the European bank in conjunction with the establishment of a VAT registration in The Netherlands	1,900,000	1,500,000				1,900,000
Fair Value Measurement
Money markets										739,000	714,000		739,000	714,000	739,000	714,000
Total debt										402,082,000	398,589,000		414,406,000	409,284,000	372,750,000	371,863,000	41,656,000	37,421,000
NEC TOKIN options, net										14,300,000	3,600,000		14,300,000	3,600,000					14,300,000	3,600,000
NEC TOKIN option valuation activity using significant unobservable inputs (Level 3)
Balance at the beginning of the period												3,600,000
Change in value of NEC TOKIN options						10,700,000	(382,000)					10,700,000
Balance at the end of the period												14,300,000
Restricted cash	12,955,000					12,955,000		13,512,000													2,100,000	1,700,000
Components of inventories
Raw materials and supplies	89,416,000					89,416,000		90,968,000
Work in process	58,363,000					58,363,000		61,310,000
Finished goods	62,358,000					62,358,000		62,522,000
Inventory, gross	210,137,000					210,137,000		214,800,000
Inventory reserves	(21,304,000)					(21,304,000)		(26,826,000)
Inventories, net	188,833,000					188,833,000		187,974,000
Reserve for inventory held by a third party			$ 3,900,000		$ 3,900,000
Warrant
Number of shares subject to a warrant held by K Equity, LLC	8,400,000	8,400,000				8,400,000		8,400,000
Revenue Recognition
Period of product warranty						1 year
Warranty costs as a percentage of net sales, maximum	1.00%	1.00%		1.00%		1.00%	1.00%