Prepaid Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Director compensation	$ 9	$ 100
Director, officer and other insurance	115	121
Marketing programs and conferences	80	53
Legal retainer	25	25
Professional service retainer	8	8
Rent	11	19
Equipment service deposits	1	3
Engineering, software licenses and other	8	13
Total prepaid expenses	$ 257	$ 342