Summary of Significant Accounting Policies - Schedule of Revenues from External Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Entity Wide Revenue Major Customer [Line Items]
Operating leases	$ 22,915	$ 16,788	$ 40,047	$ 29,417
Incentives	11,543	6,199	16,719	12,011
Operating leases and incentives	34,458	22,987	56,766	41,428
Solar energy systems and product sales	38,232	28,952	65,601	40,914
Total revenue	72,690	51,939	122,367	82,342
Solar Energy Systems
Entity Wide Revenue Major Customer [Line Items]
Solar energy systems and product sales	7,028	5,741	12,834	8,093
Products
Entity Wide Revenue Major Customer [Line Items]
Solar energy systems and product sales	$ 31,204	$ 23,211	$ 52,767	$ 32,821