Note 14 - Risks and Uncertainties (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)
Revenue from Contract with Customer, Excluding Assessed Tax	$ 24,270	$ 31,370	$ 74,302	$ 62,479
Geospace Technologies Eurasia LLC (GTE) [Member]
Imported Product for Resale			1,700		$ 3,800
Equity, Attributable to Noncontrolling Interest	5,500		5,500
Cash	2,000		2,000
Geospace Technologies Eurasia LLC (GTE) [Member] | Geographic Distribution, Domestic [Member]
Revenue from Contract with Customer, Excluding Assessed Tax			$ 1,500		$ 1,800
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers			2
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer One [Member]
Accounts and Financing Receivable, after Allowance for Credit Loss	4,000		$ 4,000
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer Two [Member]
Accounts and Financing Receivable, after Allowance for Credit Loss	$ 2,200		$ 2,200
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Number of Major Customers	2		2
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | Customer One [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,300		$ 33,700
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | Customer Two [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 3,200		$ 6,700