Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$ 165,161	$ 173,041
Sales allowances and inventory reserves	14,910	16,918
Tax credits	16,336	11,234
Medical and employee benefits	4,954	9,840
Stock-based compensation	2,501	2,576
Other	2,357	2,988
Total deferred tax assets before valuation allowance	206,219	216,597
Less valuation allowance	(163,898)	(170,917)
Total deferred tax assets	42,321	45,680
Deferred tax liabilities:
Undistributed Earnings of Foreign Subsidiaries	(20,265)	(18,271)
Depreciation and differences in basis	(7,576)	(11,718)
Amortization of intangibles and debt discounts	(6,207)	(7,107)
Non-amortized intangibles	(2,549)	(2,556)
Other	(501)	(451)
Total deferred tax liabilities	(37,098)	(40,103)
Net deferred tax assets	$ 5,223	$ 5,577