Note 10 - Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Disaggregation of Revenue [Table Text Block]

	Year Ended December 31,
	2022		2021		2020
Systems	$	560	$	1,189	$	—
Cycle units		140		229		—
Total consolidated revenue	$	700	$	1,418	$	—

Revenue from External Customers by Geographic Areas [Table Text Block]

	Year Ended December 31,
	2022		2021		2020
North America	$	517	$	1,182	$	—
Rest of World		183		236		—
Total consolidated revenue	$	700	$	1,418	$	—