Segment Information - Financial information for segments and reconciliation of Total of Reportable segments' income/(loss)from operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Consolidated contract revenue	$ 2,822	$ 3,663
Operating Loss	(4,348)	(3,700)
Reconciliation of consolidated loss from operations to consolidated net loss:
Derivative and Other	31	107
Debt accretion expense and loss on extinguishment	0	(486)
Gain from discontinued operations, net of tax	(21)	45
Net loss	(4,338)	(4,034)
Residential
Segment Reporting Information [Line Items]
Consolidated contract revenue	2,485	3,644
Operating Loss	(1,871)	(1,033)
Sunetric
Segment Reporting Information [Line Items]
Consolidated contract revenue	337	19
Operating Loss	(597)	(804)
POWERHOUSE
Segment Reporting Information [Line Items]
Consolidated contract revenue	0	0
Operating Loss	(51)	0
Other
Segment Reporting Information [Line Items]
Consolidated contract revenue	0	0
Operating Loss	$ (1,829)	$ (1,863)