Summary of Significant Accounting Policies - Schedule of Revenues from External Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Major Customer [Line Items]
Customer agreements	$ 61,649	$ 46,325
Incentives	5,341	2,765
Customer agreements and incentives	66,990	49,090
Solar energy systems and product sales	77,373	56,019
Total revenue	144,363	105,109
Solar energy systems
Revenue, Major Customer [Line Items]
Solar energy systems and product sales	37,883	20,619
Products
Revenue, Major Customer [Line Items]
Solar energy systems and product sales	$ 39,490	$ 35,400