Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued payroll and related benefits	$ 435	$ 394
Accrued sales commissions and incentives	115	124
Accrued warranty expense	258	174	$ 331
Accrued severance and related benefits	188	0
Accrued restructuring - short-term	156	170
Accrued legal and professional fees	160	77
Accrued other expenses	73	53
Total accrued liabilities	$ 1,385	$ 992