Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net income (loss)	$ 254,529	$ 47,989	$ (53,629)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	49,755	37,338	39,016
Non-cash debt and financing costs	2,467	761	859
(Gain) loss on early extinguishment of debt	486	0	0
Stock-based compensation expense	(76,192)	(41,643)	16,406
Business combination bargain purchase, gain recognized	(130,880)	0	0
Change in value of TOKIN options	0	(10,700)	26,300
Net (gain) loss on sales and disposals of assets	(1,200)
Stock-based compensation expense	7,657	4,720	4,774
Pension and other post-retirement benefits	4,717	2,543	3,013
Change in deferred income taxes	613	(19)	495
Net (gain) loss on write down and disposal of long-lived assets	(992)	10,671	375
Write down of receivables	162	64	24
Rent receivable	2,645	0	0
Other, net	(71)	(327)	306
Changes in assets and liabilities, net of the effect of acquisitions:
Accounts receivable	30,084	(12)	(2,346)
Inventories	(13,827)	16,805	3,338
Prepaid expenses and other assets	4,330	(1,769)	13,588
Accounts payable	(16,053)	6,170	(5,982)
Accrued income taxes	1,317	144	(382)
Other operating liabilities	113	(1,068)	(13,790)
Net cash provided by (used in) operating activities	120,860	71,667	32,365
Investing activities:
Capital expenditures	(65,004)	(25,617)	(20,469)
Investment in Novasentis	(3,000)	0	0
Change in restricted cash	0	0	1,802
Proceeds from dividend	2,745	0	0
Acquisitions, net of cash received	(163,985)	0	2,892
Proceeds from sale of discontinued operations	3,400
Proceeds from sale of assets	3,638	19	971
Net cash provided by (used in) investing activities	102,364	(25,598)	(20,588)
Financing activities:
Proceeds from revolving line of credit	0	12,000	10,000
Payments of revolving line of credit	(33,881)	(12,000)	(9,600)
Proceeds from issuance of debt	334,978	2,314	0
Deferred acquisition payments	0	0	(3,000)
Payment of long-term debt	(365,938)	(2,428)	(481)
Debt issuance costs	(5,002)	0	0
Proceeds from exercise of stock options	5,207	1,133	0
Proceeds from exercise of stock warrants	8,838	0	0
Purchase of treasury stock	0	(1,144)	(722)
Net cash provided by (used in) financing activities	(55,798)	(125)	(3,803)
Net increase (decrease) in cash and cash equivalents	167,426	45,944	7,974
Effect of foreign currency fluctuations on cash	9,646	(1,174)	668
Cash and cash equivalents at beginning of fiscal year	109,774	65,004	56,362
Cash and cash equivalents at end of fiscal year	286,846	109,774	65,004
Supplemental Cash Flow Statement Information:
Interest paid, net of capitalized interest	44,905	38,922	39,091
Income taxes paid	$ 7,120	$ 4,153	$ 4,892