Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Enphase
Related Party Transaction [Line Items]
Purchase from related party	$ 4.3	$ 3.3	$ 18.7	$ 8.2
Outstanding payables to related party	2.7		2.7		$ 0.7
Aquion, Inc
Related Party Transaction [Line Items]
Purchase from related party	$ 0.1		$ 0.3