Note 12 - Stock-based Compensation - Summary of the Status of the Company's Stock Options (Details)	9 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)
Outstanding (in shares) | shares	770,000
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 1.73
Outstanding, aggregate intrinsic value | $	$ 742,800	$ 352,700
Granted (in shares) | shares
Granted, weighted average exercise price (in dollars per share) | $ / shares
Exercised (in shares) | shares	123,334
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 1.20
Exercised, aggregate intrinsic value | $	$ 304,568
Expired (in shares) | shares
Expired, weighted average exercise price (in dollars per share) | $ / shares
Forfeited (in shares) | shares	(166,666)
Forfeited, weighted average exercise price (in dollars per share) | $ / shares	$ 1.35
Forfeited, aggregate intrinsic value | $	$ 347,999
Outstanding (in shares) | shares	480,000
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 1.89
Exercisable (in shares) | shares	376,667
Exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 1.99
Exercisable, aggregate intrinsic value | $	$ 546,101