Note 3 - Accounts Receivable (Details Textual) - Customer Concentration Risk [Member]	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Accounts Receivable [Member]
Number of Major Customers					3
Accounts Receivable [Member] | Customer One [Member]
Concentration Risk, Percentage	18.00%				16.00%
Accounts Receivable [Member] | Customer Two [Member]
Concentration Risk, Percentage	14.00%				14.00%
Accounts Receivable [Member] | Customer Three [Member]
Concentration Risk, Percentage					12.00%
Revenue Benchmark [Member]
Number of Major Customers	1		1	2
Revenue Benchmark [Member] | Customer One [Member]
Concentration Risk, Percentage				15.00%
Revenue Benchmark [Member] | Customer Two [Member]
Concentration Risk, Percentage				19.00%
Revenue Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage	13.00%	19.00%	12.00%