Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Sales Return Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 2,229	$ 1,726	$ 961
Additions Charged to Costs and Expenses	4,277	503	765
Deductions	0	0	0
Balance at End of Year	6,506	2,229	1,726
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	8,481	6,717	4,489
Additions Charged to Costs and Expenses	6,885	5,715	3,780
Deductions	(3,543)	(3,951)	(1,552)
Balance at End of Year	$ 11,823	$ 8,481	$ 6,717