| Note 6 - Income Taxes - Significant Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Sep. 30, 2022 | 
|---|---|---|
| Inventories | $ 2,154 | $ 813 | 
| R&D expenses | 832 | 0 | 
| Stock-based compensation | 600 | 416 | 
| Accrued expenses and reserves | 515 | 1,020 | 
| Unrealized loss on investments | 204 | 365 | 
| Net operating loss carry forwards and credits | 201 | 256 | 
| Foreign currency translation loss | 0 | 180 | 
| Total deferred tax asset | 4,506 | 3,050 | 
| Goodwill | (1,123) | (1,077) | 
| Property and equipment depreciation | (683) | (1,068) | 
| Prepaid expenses | (193) | (163) | 
| Intangibles | (153) | (102) | 
| Foreign currency translation gain | (36) | 0 | 
| Total deferred tax liability | (2,188) | (2,410) | 
| Net deferred tax asset | $ 2,318 | $ 640 | 
| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to capitalized research and development. No definition available. 
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| X | ||||||||||
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- Definition Amount of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from investments (excludes investments in subsidiaries and equity method investments). No definition available. 
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| X | ||||||||||
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- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from reserves and accruals. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses on foreign currency transactions. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from goodwill. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount of deferred tax consequences attributable to taxable temporary differences derived from prepaid expenses. No definition available. 
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| X | ||||||||||
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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| X | ||||||||||
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on foreign currency transactions. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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