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Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) - shares shares in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014 | Dec. 31, 2014
Concentration Risk [Line Items] |  |  |  |  |
Securities excluded from net loss per share calculation |  | 175 |  | 1,000 |
Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage | 82.00% | 72.00% | 85.00% | 67.00% |
Sales Revenue, Net [Member] | Geographic Concentration Risk [Member] | Countries Outside the United States [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage | 1.00% | 1.00% | 1.00% | 1.00% |
Energy Management Products, LLC [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage | 74.00% | 61.00% | 79.00% | 51.00% |
Energy Management Products, LLC [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage |  |  | 71.00% |  | 55.00%
DFAS Columbus [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage |  | 11.00% |  | 16.00% |
DFAS Columbus [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage |  |  | 18.00% |  |
ES Entegral Solutions, Inc. [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage |  |  |  |  | 20.00%
Johnson Controls, Inc. [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member] |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |
Concentration risk, percentage |  |  |  |  | 11.00%

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