Note 5 - Accrued Liabilities - Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accrued sales commission	$ 723		$ 1,743
Accrued interest	689		683
Accrued bonuses	607		837
Accrued professional fees	635		978
Accrued payroll and other related expenses	632		877
Customer contracts liabilities	552		686
Deferred revenue - systems rental program	398
Accrued clinical trial costs	346		84
Current operating lease liabilities	248	$ 230
Travel and entertainment	123		280
Accrued sales & use tax	39		259
Other accruals	286		339
Total accrued liabilities	$ 5,278	$ 6,996	$ 6,766	[1]

[1] The condensed consolidated balance sheet as of December 31, 2018 has been derived from the audited consolidated financial statements as of that date.