Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Schedule of Property Plant and Equipment Useful Life [Table Text Block]

Operating lease assets – Senhance System leasing (in years)	5
Machinery, manufacturing and demonstration equipment (in years)	3	-	5
Computer equipment (in years)	3
Furniture (in years)	5
Leasehold improvements	Lesser of lease term or 3 to 10 years

Disaggregation of Revenue [Table Text Block]

	Three Months Ended March 31,
	2021		2020
	(in thousands)
U.S.
Systems	$	93	$	30
Instruments and accessories		62		60
Services		98		69
Total U.S. revenue		253		159
Outside of U.S. ("OUS")
Systems		1,172		39
Instruments and accessories		377		113
Services		281		289
Total OUS revenue		1,830		441
Total
Systems		1,265		69
Instruments and accessories		439		173
Services		379		358
Total revenue	$	2,083	$	600