Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
May 31, 2014	May 31, 2013	May 31, 2012
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 1,984	$ 2,129	$ 1,619
Additions - Charged to costs and expenses	8,161	4,134	5,067
Deductions	(6,878)	(4,279)	(4,557)
Balance at End of Period	3,267	1,984	2,129
Allowance for deferred tax asset [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	712	1,196	1,134
Additions - Charged to costs and expenses	819	0	208
Deductions	0	(484)	(146)
Balance at End of Period	1,531	712	1,196
Allowance for sales returns and doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	1,272	933	485
Additions - Charged to costs and expenses	7,342	4,134	4,859
Deductions	(6,878)	(3,795)	(4,411)
Balance at End of Period	$ 1,736	$ 1,272	$ 933

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

+ Details

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- Definition

+ References

+ Details

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- Definition

Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

+ References

+ Details

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