Investments	9 Months Ended
Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The Company had investment securities related to certificates of deposit in the amount of $0.3 million as of September 30, 2015 and December 31, 2014. No unrealized gains or losses were recorded as of September 30, 2015 and December 31, 2014 related to these investment securities. The Company also had a cost method investment in the amount of $2.8 million as of September 30, 2015 and December 31, 2014. No unrealized gains or losses were recorded as of September 30, 2015 and December 31, 2014 related to this investment security. The Company's investment securities have maturities ranging from one to five years as of September 30, 2015. In November 2014, the Company acquired an 8% ownership interest in the common stock of Highview Enterprises Limited ("Highview"), a London, England based developmental stage company specializing in power storage, for $2.8 million in cash. The Company evaluated the investment and determined that it should account for the investment under the cost method. This investment is evaluated for impairment upon an indicator of impairment such as an event or change in circumstances that may have a significant adverse effect on the fair value of the investment. As of September 30, 2015 and December 31, 2014, no indicators of impairment had been identified. When there are no indicators of impairment present, the Company estimates the fair value for the Highview investment only if it is practical to do so. As of September 30, 2015 and December 31, 2014, the Company estimated that the fair value of the cost method investment approximated the November 2014 purchase price due to the proximity of the purchase date to December 31, 2014 and September 30, 2015.

Investments

The Company had investment securities related to certificates of deposit in the amount of $0.3 million as of September 30, 2015 and December 31, 2014. No unrealized gains or losses were recorded as of September 30, 2015 and December 31, 2014 related to these investment securities.

The Company also had a cost method investment in the amount of $2.8 million as of September 30, 2015 and December 31, 2014. No unrealized gains or losses were recorded as of September 30, 2015 and December 31, 2014 related to this investment security.

The Company's investment securities have maturities ranging from one to five years as of September 30, 2015.

In November 2014, the Company acquired an 8% ownership interest in the common stock of Highview Enterprises Limited ("Highview"), a London, England based developmental stage company specializing in power storage, for $2.8 million in cash. The Company evaluated the investment and determined that it should account for the investment under the cost method. This investment is evaluated for impairment upon an indicator of impairment such as an event or change in circumstances that may have a significant adverse effect on the fair value of the investment. As of September 30, 2015 and December 31, 2014, no indicators of impairment had been identified. When there are no indicators of impairment present, the Company estimates the fair value for the Highview investment only if it is practical to do so. As of September 30, 2015 and December 31, 2014, the Company estimated that the fair value of the cost method investment approximated the November 2014 purchase price due to the proximity of the purchase date to December 31, 2014 and September 30, 2015.