Schedule II (Schedule Of Valuation And Qualifying Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reserve For Sales Returns And Allowances [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 834	$ 207	$ 135
Additions	441	634	78
Deductions	106	7	6
Ending Balance	1,169	834	207
Allowance For Inventory Valuation [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	1,080	843	522
Additions	1,004	1,692	720
Deductions	1,195	1,455	399
Ending Balance	889	1,080	843
Valuation Allowance For Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	81,982	73,682	59,554
Additions		8,300	14,128
Deductions	15,009
Ending Balance	$ 66,973	$ 81,982	$ 73,682

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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