Note 5 - Fair Value Measurements - Fair Value by Major Security Type (Details) - USD ($)	Jun. 30, 2019	Sep. 30, 2018
Short-term Securities	$ 2,978,354	$ 3,592,175
Long-term Securities	1,499,795	1,200,541
Fair Value, Nonrecurring [Member]
Cost Basis	5,316,394	5,212,054
Unrealized Gains (Losses)	10,157	(8,945)
Fair Value	5,326,551	5,203,109
Cash Equivalents	848,402	410,393
Short-term Securities	2,978,354	3,592,175
Long-term Securities	1,499,795	1,200,541
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cost Basis	848,402	410,393
Unrealized Gains (Losses)
Fair Value	848,402	410,393
Cash Equivalents	848,402	410,393
Short-term Securities
Long-term Securities
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Cost Basis	4,467,992	4,801,661
Unrealized Gains (Losses)	10,157	(8,945)
Fair Value	4,478,149	4,792,716
Cash Equivalents
Short-term Securities	2,978,354	3,592,175
Long-term Securities	1,499,795	1,200,541
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Certificates of Deposit [Member]
Cost Basis	499,000	499,000
Unrealized Gains (Losses)
Fair Value	499,000	499,000
Cash Equivalents
Short-term Securities
Long-term Securities	499,000	499,000
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Cost Basis
Unrealized Gains (Losses)
Fair Value
Cash Equivalents
Short-term Securities
Long-term Securities
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Cost Basis	3,968,992	4,302,661
Unrealized Gains (Losses)	10,157	(8,945)
Fair Value	3,979,149	4,293,716
Cash Equivalents
Short-term Securities	2,978,354	3,592,175
Long-term Securities	$ 1,000,795	$ 701,541

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amount before tax of unrealized gain (loss) in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of investment in marketable security, classified as current.

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Amount of investment in marketable security, classified as noncurrent.

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