Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	$ 5,783	$ 10,694
Cost of customer agreements and incentives
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	632	611
Cost of solar energy systems and product sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	167	170
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	1,128	4,150
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	336	295
General and administration
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense recognized	$ 3,520	$ 5,468