Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Enphase Energy I N C
Related Party Transaction [Line Items]
Purchase from related party	$ 3.3	$ 3.1	$ 8.2	$ 6.0
Outstanding payables to related party	3.7		3.7		$ 1.1
RECC
Related Party Transaction [Line Items]
Solar energy systems and products sales revenue	0.0	$ 3.8	0.3	$ 7.6
Accounts receivable	$ 0.0		$ 0.0		$ 0.1