Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Total revenue	$ 24,270	$ 31,370	$ 74,302	$ 62,479
Product [Member]
Total revenue	19,497	17,701	63,211	37,249
Operating Segments [Member] | Oil and Gas Markets [Member]
Total revenue	10,847	18,419	50,756	38,567
Operating Segments [Member] | Oil and Gas Markets [Member] | Traditional Exploration Product Revenue [Member]
Total revenue	3,472	3,296	5,234	6,051
Operating Segments [Member] | Oil and Gas Markets [Member] | Wireless Exploration Product Revenue [Member]
Total revenue	2,679	1,411	34,548	7,170
Operating Segments [Member] | Oil and Gas Markets [Member] | Reservoir Product Revenue [Member]
Total revenue	41	132	114	287
Operating Segments [Member] | Oil and Gas Markets [Member] | Product [Member]
Total revenue	6,192	4,839	39,896	13,508
Operating Segments [Member] | Adjacent Markets [Member]
Total revenue	12,235	12,708	22,050	23,530
Operating Segments [Member] | Adjacent Markets [Member] | Product [Member]
Total revenue	12,192	12,671	21,968	23,457
Operating Segments [Member] | Adjacent Markets [Member] | Industrial Product [Member]
Total revenue	9,023	9,642	15,466	17,572
Operating Segments [Member] | Adjacent Markets [Member] | Imaging Products [Member]
Total revenue	3,169	3,029	6,502	5,885
Operating Segments [Member] | Emerging Markets [Member]
Total revenue	1,113	191	1,347	284
Operating Segments [Member] | Emerging Markets [Member] | Product [Member]
Total revenue	$ 1,113	$ 191	$ 1,347	$ 284