Details of Certain Balance Sheet Accounts (Details) (USD $) In Thousands	6 Months Ended
	Sep. 30, 2011	Mar. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable	$ 125,245	$ 125,137
Accounts receivable, net	103,026	103,289
Inventory, net [Abstract]
Raw materials	16,176	15,315
Work in process	3,026	2,558
Finished goods	41,515	38,600
Inventory, Net	60,717	56,473
Accrued Liabilities [Abstract]
Employee compensation and benefits	23,396	27,478
Warranty obligation accrual	13,379	11,016
Accrued advertising and sales and marketing	2,071	2,873
Accrued other	12,483	18,240
Accrued liabilities	51,329	59,607
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty obligation accrual at March 31, 2011	11,016
Warranty provision relating to products shipped	9,139
Deductions for warranty claims processed	(6,776)
Warranty obligation accrual at September 30, 2011	13,379
Provision For Returns [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable Reserves	(8,176)	(10,437)
Provision For Promotions, Rebates And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable Reserves	(13,394)	(10,460)
Provision For Doubtful Accounts And Sales Allowances [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable Reserves	$ (649)	$ (951)