Note 3 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue	$ 1,081	$ 994	$ 2,057	$ 2,060
UNITED STATES
Revenue	133	144	339	395
Non-US [Member]
Revenue	948	850	1,718	1,665
Systems [Member]
Revenue	0	0	0	0
Systems [Member] | UNITED STATES
Revenue	0	0	0	0
Systems [Member] | Non-US [Member]
Revenue	0	0	0	0
Instruments and Accessories [Member]
Revenue	298	254	591	601
Instruments and Accessories [Member] | UNITED STATES
Revenue	38	18	98	82
Instruments and Accessories [Member] | Non-US [Member]
Revenue	260	236	493	519
Service [Member]
Revenue	289	424	484	732
Service [Member] | UNITED STATES
Revenue	76	75	151	149
Service [Member] | Non-US [Member]
Revenue	213	349	333	583
Lease [Member]
Revenue	494	316	982	727
Lease [Member] | UNITED STATES
Revenue	19	51	90	164
Lease [Member] | Non-US [Member]
Revenue	$ 475	$ 265	$ 892	$ 563