Segment Information - Financial information for segments and reconciliation of Total of Reportable segments' income/(loss)from operations (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net revenue		$ 10,438	$ 18,900	$ 35,775	$ 52,302
Loss from operations		(4,485)	(9,249)	(12,528)	(21,766)
Other income				147
Interest expense		(54)	(340)	(423)	(795)
Change in valuation of warrants		660	6,789	6,924	8,204
Income tax (expense)/benefit		(2)	287	22	1,496
Loss from discontinued operations, net of tax		(397)	(2,237)	(712)	(28,071)
Net loss		(4,278)	(4,750)	(6,570)	(40,932)
Residential
Segment Reporting Information [Line Items]
Net revenue		6,894	14,358	24,861	43,573
Loss from operations		(1,809)	(3,393)	(4,787)	(7,345)
Sunetric
Segment Reporting Information [Line Items]
Net revenue	[1]	3,544	3,803	10,914	6,875
Loss from operations	[1]	$ 110	(1,396)	$ (41)	(1,545)
Other
Segment Reporting Information [Line Items]
Net revenue			739		1,854
Loss from operations		$ (2,786)	$ (4,460)	$ (7,700)	$ (12,876)

[1] Sunetric amounts for the nine months ended 2014 are for the period of May 14, 2014, the acquisition date, through September 30, 2014.