Significant Customers (Details Textual) - customer	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Significant Customers (Textual) [Abstract]
Numbers of customers	2	2	2	2
Significant Customers
Revenues attributable to sales [Line Items]
Total	29.00%	27.50%	29.10%	33.40%
Significant Customers | Avnet
Revenues attributable to sales [Line Items]
Total	29.00%	27.50%	29.10%	28.10%
Significant Customers | Enel
Revenues attributable to sales [Line Items]
Total	0.00%	0.00%	0.00%	5.30%