Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued payroll and related benefits	$ 394	$ 522
Accrued sales commissions and incentives	124	325
Accrued warranty expense	174	331	$ 314
Restructuring Reserve, Current	170	0
Accrued restructuring - short-term	0	328
Accrued legal and professional fees	77	63
Accrued other expenses	53	107
Total accrued liabilities	$ 992	$ 1,676