Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Deferred tax assets:
Net operating loss carry forwards	$ 78,986	$ 115,064
Sales allowances and inventory reserves	10,967	9,675
Medical and employee benefits	35,298	38,572
Depreciation and differences in basis	5,318	6,241
Accrued restructuring	469	2,551
Anti-trust fines and settlements	910	16,575
Tax credits	3,394	4,208
Stock-based compensation	5,589	1,765
Other(1)	1,342	2,812
Total deferred tax assets before valuation allowance	142,273	197,463
Less valuation allowance	(58,658)	(171,401)
Total deferred tax assets	83,615	26,062
Deferred tax liabilities:
Unremitted earnings of subsidiaries	(21,850)	(11,678)
Amortization of intangibles and debt discounts	(11,996)	(14,054)
Non-amortized intangibles	(1,551)	(1,551)
Total deferred tax liabilities	(35,397)	(27,283)
Net deferred tax assets (liabilities)	$ 48,218
Net deferred tax assets (liabilities)		$ (1,221)