Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Discontinued Operations [Abstract]
Disposal Group, Including Discontinued Operation, Description and Timing of Disposal									9/30/2014
Proceeds from divestiture of Grid business, net of transaction costs						$ 4,900			$ 0		$ 2,144		$ 0
Supply commitment term		39 months
Restructuring Costs in Discontinued Operations									1,400
Revenues											18,392		40,303
Cost of revenues											11,774		24,988
Operating expenses											15,614		18,994
Loss from discontinued operations before income taxes											(8,996)		(3,679)
Income taxes											0		0
Loss on sale of Grid business									0		(254)		0
Net loss from discontinued operations, net of income taxes	$ 0	$ 0	$ 0	$ 0	$ 0	(2,141)	$ (5,579)	$ (1,530)	0	[1]	(9,250)	[1]	(3,679)	[1]
Net loss from discontinued operations attributable to non-controlling interest, net of income taxes	0	0	0	0	0	(179)	(239)	(117)	0		(535)		(808)
Net loss from discontinued operations attributable to Echelon Corporation Stockholders, net of income taxes	$ 0	$ 0	$ 0	$ 0	$ 0	$ (1,962)	$ (5,340)	$ (1,413)	$ 0		(8,715)		(2,871)
Revenues from related parties, discontinued operations											$ 112		$ 4,400

[1] See Note 8 for summary of amounts included representing stock-based compensation expense.