Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Accounts receivable	$ 660	$ 1,111
Inventories	4,345	6,707
Net operating loss carryforwards	67,834	71,773
Accrued expenses	32,773	26,997
Other assets	9,703	10,228
Gross deferred tax assets	115,315	116,816
Less valuation allowance	(54,542)	(56,359)
Total deferred tax assets	60,773	60,457
Property, plant and equipment	28,985	30,957
Other intangible assets	48,142	46,628
Convertible Notes	22,386	21,616
Other liabilities	865	2,400
Total deferred tax liabilities	100,378	101,601
Net deferred tax liabilities	$ (39,605)	$ (41,144)