Segment Information - Reconciliation of reportable segments' assets to consolidated total assets (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 12,186	$ 14,258
Continuing Operations
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10,532	12,437
Continuing Operations | Residential
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	6,284	5,877
Continuing Operations | Sunetric
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,412	2,142
Continuing Operations | POWERHOUSE
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,226	1,140
Continuing Operations | Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,610	3,278
Discontinued Operations | Commercial Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,654	$ 1,821