Significant Customers (Details) - customer	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues attributable to sales [Line Items]
Number of Customers	1	2
Total	32.80%	37.20%	33.90%
Avnet
Revenues attributable to sales [Line Items]
Total	28.70%	24.50%	26.20%
Cancellation notice period	90 days
Enel
Revenues attributable to sales [Line Items]
Total	4.10%	12.70%	7.70%