Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues [Abstract]
Net sales	$ 187,308	$ 186,123	$ 372,243	$ 373,713
Operating costs and expenses:
Cost of sales	140,895	143,317	283,307	291,194
Selling, general and administrative expenses	25,972	22,948	51,886	53,378
Research and development	7,116	6,152	14,048	12,426
Restructuring charges	3,998	23	4,686	1,847
Write down of long-lived assets	6,193	0	6,193	0
Net (gain) loss on sales and disposals of assets	84	(304)	175	(362)
Total operating costs and expenses	184,258	172,136	360,295	358,483
Operating income (loss)	3,050	13,987	11,948	15,230
Non-operating (income) expense:
Interest income	(6)	(3)	(9)	(6)
Interest expense	9,910	9,811	19,833	19,824
Change in value of NEC TOKIN option	(1,600)	(2,200)	10,400	27,000
Other (income) expense, net	(905)	(2,091)	(3,299)	(1,175)
Income (loss) from continuing operations before income taxes and equity income (loss) from NEC TOKIN	(4,349)	8,470	(14,977)	(30,413)
Income tax expense (benefit)	830	1,438	2,630	1,190
Income (loss) from continuing operations before equity income (loss) from NEC TOKIN	(5,179)	7,032	(17,607)	(31,603)
Equity income (loss) from NEC TOKIN	181	162	404	1,747
Net income (loss)	$ (4,998)	$ 7,194	$ (17,203)	$ (29,856)
Net income (loss) per basic share:
Net income (loss) per basic share (in usd per share)	$ (0.11)	$ 0.16	$ (0.37)	$ (0.65)
Net income (loss) per diluted share (in usd per share)	$ (0.11)	$ 0.14	$ (0.37)	$ (0.65)
Weighted-average shares outstanding:
Basic (in shares)	46,590	45,767	46,471	45,660
Diluted (in shares)	46,590	50,004	46,471	45,660