Note 1 - Basis of Presentation and Significant Accounting Policies (Tables)

6 Months Ended

Mar. 31, 2022

Notes Tables

Investment in Sales-type Leases [Table Text Block]

Investment in sales-type lease, gross:
2022	$	204
2023		187
2024		186
2025		77
Gross investment in sales-type lease		654
Less: Unearned income		—
Total investment in sales-type lease	$	654
Current portion of total investment in sales-type lease	$	278
Long-term portion of total investment in sales-type lease		376
	$	654

Schedule of Inventory, Current [Table Text Block]

	March 31,			September 30,
	2022			2021
Raw materials and supplies	$	263		$	301
Finished goods		968			247
Less: Obsolescence reserve		(106	)		(106	)
	$	1,125		$	442

Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]

March 31, 2022	Level 1		Level 2		Level 3		Total Fair Value
Derivative liability	$	—	$	23	$	—	$	23

September 30, 2021	Level 1		Level 2		Level 3		Total Fair Value
Derivative liability	$	—	$	53	$	—	$	53

Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

	Six Months Ended
	March 31,
	2022		2021
Expected life (in years)		5.3		4.7
Risk-free interest rate		1.07 - 1.87%		0.33% - 0.40%
Expected volatility		64.83% - 65.49%		82.26% - 83.29%
Expected forfeiture rate		14.65% - 15.03%		14.18%
Expected exercise factor		2.0		1.2
Expected dividend yield		0.00%		0.00%

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

				Weighted-		Weighted-Average
				Average		Remaining Contractual
	Options			Exercise Price		Period in Years
Outstanding at October 1, 2021		1,853,479		$	4.44		4.60
Granted		851,250			3.23		9.87
Exercised		(66,851	)		1.59		6.90
Forfeited and cancelled		(158,519	)		5.92		—
Outstanding at March 31, 2022		2,479,359		$	4.00		7.16
Exercisable at March 31, 2022		1,348,377		$	4.63		5.34

Schedule of Nonvested Share Activity [Table Text Block]

				Weighted-Average
				Grant Date Fair
Non-vested Options	Options			Value
Non-vested at October 1, 2021		583,458		$	1.40
Granted		851,250			1.43
Vested		(272,900	)		1.06
Forfeited		(26,009	)		1.40
Non-vested at March 31, 2022		1,135,799		$	1.50

Schedule of Weighted Average Number of Shares [Table Text Block]

	Three Months Ended				Six Months Ended
	March 31,				March 31,
	2022		2021		2022		2021
Denominator for basic net income (loss) per share - weighted average common shares		9,114,451		8,040,513		9,095,810		8,001,723
Effect of dilutive options and warrants (treasury method)		—		517,275		—		450,190
Denominator for diluted net income (loss) per share - adjusted weighted average common shares		9,114,451		8,557,788		9,095,810		8,451,913
Options, warrants and convertible shares outstanding during each period, but not included in the computation of diluted net loss per share because they are antidilutive		2,919,809		1,036,907		2,919,809		1,289,407