Basis of Financial Statement Presentation (Details) Share data in Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013 USD ($)	Jun. 30, 2012	Mar. 31, 2013 USD ($)	Aug. 28, 2012 USD ($)	Aug. 31, 2006 USD ($)	Aug. 31, 2006 EUR (€)	Jun. 30, 2013 Carrying Value USD ($)	Mar. 31, 2013 Carrying Value USD ($)	Jun. 30, 2013 Recurring Fair Value USD ($)	Mar. 31, 2013 Recurring Fair Value USD ($)	Jun. 30, 2013 Recurring Level 1 Fair Value USD ($)	Mar. 31, 2013 Recurring Level 1 Fair Value USD ($)	Jun. 30, 2013 Recurring Level 2 Fair Value USD ($)	Mar. 31, 2013 Recurring Level 2 Fair Value USD ($)	Jun. 30, 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	10,300,000
Prepayment received from an OEM classified as restricted cash	13,700,000
Guarantee issued by the European bank in conjunction with the establishment of a VAT registration in The Netherlands					2,000,000	1,500,000
Deposits pledged to European bank					2,200,000	1,700,000
Fair Value Measurement
Money markets							8,585,000	29,984,000	8,585,000	29,984,000	8,585,000	29,984,000
Long-term debt							383,293,000	383,500,000	384,249,000	393,928,000	361,213,000	369,200,000	23,036,000	24,728,000
NEC TOKIN derivative							489,000	489,000	489,000	489,000					489,000	489,000
Components of inventories
Raw materials and supplies	99,634,000		84,852,000
Work in process	71,352,000		70,522,000
Finished goods	70,782,000		68,705,000
Inventory, gross	241,768,000		224,079,000
Inventory reserves	(24,225,000)		(18,464,000)
Inventories, net	217,543,000		205,615,000
Reserve for inventory held by a third party	$ 3,900,000
Warrant Liability
Number of shares subject to a warrant held by K Equity, LLC	8.4		8.4
Revenue Recognition
Period of product warranty	1 year
Warranty costs as a percentage of net sales, maximum	1.00%	1.00%