Note 3 - Accounts Receivable (Details Textual) - Customer Concentration Risk [Member]	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable [Member]
Number of Major Customers	3	3
Accounts Receivable [Member] | Customer One [Member]
Concentration Risk, Percentage	15.00%	16.00%
Accounts Receivable [Member] | Customer Two [Member]
Concentration Risk, Percentage	14.00%	14.00%
Accounts Receivable [Member] | Customer Three [Member]
Concentration Risk, Percentage	10.00%	12.00%
Revenue Benchmark [Member]
Number of Major Customers	1	2
Concentration Risk, Percentage	12.00%
Revenue Benchmark [Member] | Customer One [Member]
Concentration Risk, Percentage		11.00%
Revenue Benchmark [Member] | Customer Two [Member]
Concentration Risk, Percentage		15.00%