Note 13 - Stockholders' Equity (Details Textual) - USD ($) $ in Millions		12 Months Ended
	May 04, 2016	Sep. 30, 2021	Sep. 30, 2020
Stock Repurchase Program, Period in Force (Year)	2 years
Stock Repurchase Program, Authorized Amount	$ 10.0
Stock Repurchased During Period, Shares (in shares)		0	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 8.3
Stock Issued During Period, Shares, Treasury Stock Reissued for Equity-based Compensation Obligations (in shares)		0	47,222
Stock Issued During Period, Value, Treasury Stock Reissued for Equity-based Compensation Obligations			$ 0.4
Treasury Stock, Shares, Ending Balance (in shares)		0	0