Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Total revenue	$ 37,223	$ 50,032
Product [Member]
Total revenue	32,645	43,714
Operating Segments [Member] | Smart Water [Member]
Total revenue	7,288	4,234
Operating Segments [Member] | Smart Water [Member] | Product [Member]
Total revenue	7,288	4,234
Operating Segments [Member] | Energy Solutions [Member]
Total revenue	24,282	39,911
Operating Segments [Member] | Energy Solutions [Member] | Product [Member]
Total revenue	19,826	33,706
Operating Segments [Member] | Intelligent Industrial [Member]
Total revenue	5,577	5,813
Operating Segments [Member] | Intelligent Industrial [Member] | Product [Member]
Total revenue	$ 5,531	$ 5,774