Prepaid Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Director compensation	$ 86	$ 215
Director and officer insurance	98	70
Legal retainer	25	25
Rent	25	17
Engineering, software licenses and other	13	10
Total prepaid expenses	$ 247	$ 337