Related Parties	3 Months Ended
Mar. 31, 2017
Related Party Transactions [Abstract]
Related Parties	Related Parties: In June 2000, the Company entered into a stock purchase agreement with Enel pursuant to which Enel purchased 300,000 newly issued shares of its common stock for $130.7 million. The closing of this stock purchase occurred on September 11, 2000. At the closing, Enel had agreed that it would not, except under limited circumstances, sell or otherwise transfer any of those shares for a specified time period. That time period expired September 11, 2003. To the Company’s knowledge, Enel has disposed of none of its 300,000 shares. Under the terms of the stock purchase agreement, Enel has the right to nominate one member of the Company’s board of directors. While a representative of Enel served on the board until March 14, 2012, no Enel representative is presently on the board. In October 2006, the Company entered into a new development and supply agreement with Enel. Under the development and supply agreement, Enel and its contract manufacturers purchase additional electronic components and finished goods from the Company. The development and supply agreement expired in March 2016. For the three months ended March 31, 2017 and 2016, the Company recognized revenue from products sold to Enel and its designated manufacturers of approximately $0 and $1.3 million, respectively. As of March 31, 2017 and December 31, 2016, none of the Company’s total accounts receivable balance related to amounts owed by Enel and its designated manufacturers.

Related Parties

3 Months Ended

Mar. 31, 2017

Related Parties:

In June 2000, the Company entered into a stock purchase agreement with Enel pursuant to which Enel purchased 300,000 newly issued shares of its common stock for $130.7 million. The closing of this stock purchase occurred on September 11, 2000. At the closing, Enel had agreed that it would not, except under limited circumstances, sell or otherwise transfer any of those shares for a specified time period. That time period expired September 11, 2003. To the Company’s knowledge, Enel has disposed of none of its 300,000 shares. Under the terms of the stock purchase agreement, Enel has the right to nominate one member of the Company’s board of directors. While a representative of Enel served on the board until March 14, 2012, no Enel representative is presently on the board.

In October 2006, the Company entered into a new development and supply agreement with Enel. Under the development and supply agreement, Enel and its contract manufacturers purchase additional electronic components and finished goods from the Company. The development and supply agreement expired in March 2016.

For the three months ended March 31, 2017 and 2016, the Company recognized revenue from products sold to Enel and its designated manufacturers of approximately $0 and $1.3 million, respectively.

As of March 31, 2017 and December 31, 2016, none of the Company’s total accounts receivable balance related to amounts owed by Enel and its designated manufacturers.