Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Deferred tax assets:
Net operating loss carry forwards	$ 173,377	$ 154,841
Sales allowances and inventory reserves	19,447	14,683
Tax credits	10,838	11,664
Medical and employee benefits	10,035	7,868
Stock options	4,439	3,416
Other	4,338	4,615
Total deferred tax assets before valuation allowance	222,474	197,087
Less valuation allowance	(189,276)	(169,270)
Total deferred tax assets	33,198	27,817
Deferred tax liabilities:
Depreciation and differences in basis	(13,299)	(14,629)
Amortization of intangibles and debt discounts	(7,420)	(6,978)
Non-amortized intangibles	(2,549)	(2,542)
Other	(1,682)	(72)
Total deferred tax liabilities	(24,950)	(24,221)
Net deferred tax asset	$ 8,248	$ 3,596