Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Deferred tax assets:
Net operating loss carry forwards	$ 173,041	$ 162,691
Sales allowances and inventory reserves	16,918	21,696
Tax credits	11,234	15,982
Medical and employee benefits	9,840	10,025
Stock-based compensation	2,576	3,578
Other	2,988	3,411
Total deferred tax assets before valuation allowance	216,597	217,383
Less valuation allowance	(170,917)	(167,594)
Total deferred tax assets	45,680	49,789
Deferred tax liabilities:
Undistributed Earnings of Foreign Subsidiaries	(18,271)	(18,502)
Depreciation and differences in basis	(11,718)	(12,166)
Amortization of intangibles and debt discounts	(7,107)	(7,261)
Deferred Tax Liabilities, Investments	0	(1,860)
Non-amortized intangibles	(2,556)	(2,556)
Other	(451)	(54)
Total deferred tax liabilities	(40,103)	(42,399)
Net deferred tax assets	$ 5,577	$ 7,390