Revenues Revenues (Details Textual)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Distributor One
Disaggregation of Revenue [Line Items]
Percentage of revenues from major distributors	34.00%	36.80%
Distributor Two
Disaggregation of Revenue [Line Items]
Percentage of revenues from major distributors	15.90%	19.30%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration