Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Deferred tax assets:
Net operating loss carry forwards	$ 115,064	$ 165,161
Sales allowances and inventory reserves	9,675	14,910
Medical and employee benefits	38,572	16,336
Depreciation and differences in basis	6,241	0
Accrued restructuring	2,551	0
Anti-trust fines and settlements	16,575	0
Tax credits	4,208	4,954
Stock-based compensation	1,765	2,501
Other	3,299	2,357
Total deferred tax assets before valuation allowance	197,950	206,219
Less valuation allowance	(171,401)	(163,898)
Total deferred tax assets	26,549	42,321
Deferred tax liabilities:
Unremitted earnings of subsidiaries	(11,678)	(20,265)
Depreciation and differences in basis	0	(7,802)
Amortization of intangibles and debt discounts	(14,054)	(6,207)
Non-amortized intangibles (1)	(1,551)	(2,549)
Other	0	(501)
Total deferred tax liabilities	(27,283)	(37,324)
Net deferred tax assets (liabilities)	$ (734)
Net deferred tax assets (liabilities)		$ 4,997