Valuation and Qualifying accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Opening Balance	$ 353	$ 430	$ 390
Valuation Allowances and Reserves, Charged to Cost and Expense	(46)	55	48
Valuation Allowances and Reserves, Adjustments	250	132	8
Valuation Allowances and Reserves, Closing Balance	57	353	430
Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Opening Balance	530	429	1,411
Valuation Allowances and Reserves, Charged to Cost and Expense	3,729	5,375	4,265
Valuation Allowances and Reserves, Adjustments	3,858	5,274	5,247
Valuation Allowances and Reserves, Closing Balance	$ 401	$ 530	$ 429

Total of the adjustments 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.

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

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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.

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