Note 3 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue	$ 7,087	$ 8,232
UNITED STATES
Revenue	767	1,033
Non-US [Member]
Revenue	6,320	7,199
Systems [Member]
Revenue	2,551	3,286
Systems [Member] | UNITED STATES
Revenue	0	0
Systems [Member] | Non-US [Member]
Revenue	2,551	3,286
Instruments and Accessories [Member]
Revenue	1,776	2,113
Instruments and Accessories [Member] | UNITED STATES
Revenue	211	273
Instruments and Accessories [Member] | Non-US [Member]
Revenue	1,565	1,840
Service [Member]
Revenue	1,373	1,520
Service [Member] | UNITED STATES
Revenue	300	383
Service [Member] | Non-US [Member]
Revenue	1,073	1,137
Lease [Member]
Revenue	1,387	1,313
Lease [Member] | UNITED STATES
Revenue	256	377
Lease [Member] | Non-US [Member]
Revenue	$ 1,131	$ 936