Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Revenues:				$ 3,539
Cost of revenues				100
Gross profit				3,439
Operating expenses:
Engineering and product development				143
Selling and marketing				620
General and administrative				2,342
Other income, net		$ 183		2,467
Loss on disposal of assets		594		4,845
Income (loss) from discontinued operations before interest and other financing expense, net		(777)		(5,483)
Interest and other financing expense, net				(77)
Income (loss) from discontinued operations before income taxes		(777)		(2,121)
Income tax expenses allocated to discontinued operations		(20)		(114)
Income (loss) from discontinued operations	66	(797)	$ 286	(2,235)
Gain from disposal of discontinued operations, net of taxes	66		286
Net gain (loss) from discontinued operations	$ (66)	$ 797	$ (286)	$ 2,235