Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Revenue from Contract with Customer, Excluding Assessed Tax	$ 135,598	$ 124,509
Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	116,036	73,333
Operating Segments [Member] | Oil and Gas Markets [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	77,455	73,993
Operating Segments [Member] | Oil and Gas Markets [Member] | Traditional Exploration Product Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	9,666	12,081
Operating Segments [Member] | Oil and Gas Markets [Member] | Wireless Exploration Product Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	48,094	10,168
Operating Segments [Member] | Oil and Gas Markets [Member] | Reservoir Product Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	596	962
Operating Segments [Member] | Oil and Gas Markets [Member] | Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	58,356	23,211
Operating Segments [Member] | Adjacent Markets [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	55,625	49,039
Operating Segments [Member] | Adjacent Markets [Member] | Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	55,458	48,888
Operating Segments [Member] | Adjacent Markets [Member] | Industrial Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	43,058	36,859
Operating Segments [Member] | Adjacent Markets [Member] | Imaging Products [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	12,400	12,029
Operating Segments [Member] | Emerging Markets [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2,222	1,234
Operating Segments [Member] | Emerging Markets [Member] | Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,222	$ 1,234