Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Total revenue	$ 31,370	$ 24,700	$ 62,479	$ 42,691
Product [Member]
Total revenue	17,701	21,565	37,249	34,597
Operating Segments [Member] | Oil and Gas Markets [Member]
Total revenue	18,419	15,146	38,567	24,800
Operating Segments [Member] | Oil and Gas Markets [Member] | Traditional Exploration Product Revenue [Member]
Total revenue	3,296	1,217	6,051	1,797
Operating Segments [Member] | Oil and Gas Markets [Member] | Wireless Exploration Product Revenue [Member]
Total revenue	1,411	10,500	7,170	14,258
Operating Segments [Member] | Oil and Gas Markets [Member] | Reservoir Product Revenue [Member]
Total revenue	132	394	287	821
Operating Segments [Member] | Oil and Gas Markets [Member] | Product [Member]
Total revenue	4,839	12,111	13,508	16,876
Operating Segments [Member] | Adjacent Markets [Member]
Total revenue	12,708	9,203	23,530	17,374
Operating Segments [Member] | Adjacent Markets [Member] | Product [Member]
Total revenue	12,671	9,155	23,457	17,285
Operating Segments [Member] | Adjacent Markets [Member] | Industrial Product [Member]
Total revenue	9,642	5,993	17,572	11,006
Operating Segments [Member] | Adjacent Markets [Member] | Imaging Products [Member]
Total revenue	3,029	3,162	5,885	6,279
Operating Segments [Member] | Emerging Markets [Member]
Total revenue	191	299	284	436
Operating Segments [Member] | Emerging Markets [Member] | Product [Member]
Total revenue	$ 191	$ 299	$ 284	$ 436