Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2021

Notes Tables

Investments Classified by Contractual Maturity Date [Table Text Block]

	September 30, 2021		September 30, 2020
Less than one year	$	10,373,831	$	10,582,527
1-5 years		36,912,777		25,143,000
Total	$	47,286,608	$	35,725,527

Financing Receivable, Allowance for Credit Loss [Table Text Block]

Year Ended	Balance at Beginning of Year		Additions (Recoveries) Charged to Costs and Expenses			Less Write-offs		Balance at End of Year
September 30, 2021	$	289,085	$	(209,612	)	$	-	$	79,473
September 30, 2020	$	289,085	$	-		$	-	$	289,085

Schedule of Inventory, Current [Table Text Block]

	September 30, 2021			September 30, 2020
Raw materials	$	23,071,833		$	12,287,134
Work-in-process		2,481,890			1,033,021
Finished goods		3,361,576			2,048,514
Inventories, gross		28,915,299			15,368,669
Inventory reserve		(1,390,988	)		(960,131	)
Inventories, net	$	27,524,311		$	14,408,538

Property, Plant and Equipment [Table Text Block]

	September 30, 2021		September 30, 2020
Manufacturing equipment	$	9,178,935	$	8,171,497
Office equipment		2,901,385		2,478,056
Leasehold improvements		2,589,777		2,576,861
Vehicles		245,903		245,903
Construction in progress		150,343		19,143
Property, plant and equipment, gross		15,066,343		13,491,460
Less accumulated depreciation		10,068,685		8,538,641
Property, plant and equipment, net	$	4,997,658	$	4,952,819

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	September 30, 2021
	Years				Gross Carrying Amount		Accumulated Amortization		Net Book Value Amount
Customer relationships		15			$	3,742,000	$	904,317	$	2,837,683
Certifications		8				1,068,000		483,937		584,063
Trademarks		8				563,000		255,109		307,891
Patents		20				790,384		84,660		705,724
Other		5				31,091		24,873		6,218
Software		1	-	3		1,959,670		1,705,098		254,572
Totals					$	8,154,145	$	3,457,994	$	4,696,151

	September 30, 2020
	Years				Gross Carrying Amount		Accumulated Amortization		Net Book Value Amount
Customer relationships		15			$	3,742,000	$	654,850	$	3,087,150
Certifications		8				1,068,000		350,437		717,563
Trademarks		8				563,000		184,734		378,266
Patents		20				689,889		56,257		633,632
Other		5				31,091		18,655		12,436
Software		1	-	3		1,695,559		1,538,390		157,169
Totals					$	7,789,539	$	2,803,323	$	4,986,216

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

	Estimated amortization expense
FY 2022	$	592,192
FY 2023		531,237
FY 2024		497,387
FY 2025		453,342
FY 2026		325,920
Total	$	2,400,078

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

Year ended September 30,	2021		2020
Net income	$	20,327,380	$	7,293,066
Weighted average common shares		13,720,699		13,643,355
Dilutive potential common shares		63,594		-
Weighted average dilutive common shares outstanding		13,784,293		13,643,355
Earnings per share:
Basic	$	1.48	$	0.53
Diluted	$	1.47	$	0.53

Useful Lives [Member]

Notes Tables

Property, Plant and Equipment [Table Text Block]

	Years
Equipment	3 – 7
Leasehold improvements	7-10 or life of lease
Vehicles	3