Note 11 - Stockholders' Equity - Summary of Changes in Stockholders' Equity (Details) - USD ($)	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Balances	$ 35,184,039
Share-based compensation expense	$ 138,461
Issuance of common stock upon exercise of stock options, net (in shares)	90,852
Issuance of common stock upon exercise of stock options, net	$ 159,518
Other comprehensive loss	(8,031)	$ (6,310)
Net loss	(1,683,253)	$ (812,680)
Balances	$ 33,790,734
Common Stock [Member]
Balances (in shares)	32,158,436
Balances	$ 322
Issuance of common stock upon exercise of stock options, net (in shares)	90,852
Balances (in shares)	32,249,288
Balances	$ 322
Additional Paid-in Capital [Member]
Balances	87,956,839
Share-based compensation expense	138,461
Issuance of common stock upon exercise of stock options, net	159,518
Balances	88,254,818
Retained Earnings [Member]
Balances	(52,771,853)
Net loss	(1,683,253)
Balances	(54,455,106)
AOCI Attributable to Parent [Member]
Balances	(1,269)
Other comprehensive loss	(8,031)
Balances	$ (9,300)