Summary of Significant Accounting Policies (Tables)

12 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Summary of the activity in allowance for doubtful accounts

A summary of the activity in our allowance for doubtful accounts is as follows:

Years Ended	March 31, 2021			March 31, 2020
Balance, beginning of year	$	58,000		$	26,000
Provision for (recoveries of) estimated losses		(16,322	)		32,168
Write-off of uncollectible accounts		(6,678	)		(168	)
Balance, end of year	$	35,000		$	58,000

Schedule of inventory

At March 31, 2021 and 2020, inventory consisted of the following:

	March 31, 2021			March 31, 2020
Raw materials	$	1,038,094		$	1,147,983
Finished goods		477,040			516,918
Total gross inventories		1,515,134			1,664,901
Less reserve for obsolescence		(70,000	)		(39,000	)
Total net inventories	$	1,445,134		$	1,625,901

Summary of the activity in inventory reserve for obsolescence

A summary of the activity in our inventory reserve for obsolescence is as follows:

Years Ended	March 31, 2021			March 31, 2020
Balance, beginning of year	$	39,000		$	50,000
Provision for estimated obsolescence		31,528			(11,000	)
Write-off of obsolete inventory		(528	)		—
Balance, end of year	$	70,000		$	39,000

Summary of patents

A summary of our patents at March 31, 2021 and 2020 is as follows:

	March 31, 2021			March 31, 2020
Patents issued	$	496,901		$	473,607
Accumulated amortization		(308,155	)		(281,649	)
Patents issued, net of accumulated amortization		188,746			191,958
Patent applications		34,288			46,026
Accumulated amortization		(9,666	)		(9,688	)
Patent applications, net of accumulated amortization		24,622			36,338
Total net patents and patent applications	$	213,368		$	228,296

Schedule of expected annual amortization expense related to patents and patent applications for the next five fiscal years

The expected annual amortization expense related to patents and patent applications as of March 31, 2021, for the next five fiscal years, is as follows:

Fiscal Year		Amount
	2022		24,705
	2023		24,705
	2024		21,787
	2025		21,037
	2026		20,220
	Thereafter		100,914
	Total	$	213,368

Schedule of other accrued liabilities

Other Accrued Liabilities. At March 31, 2021 and 2020, other accrued liabilities consisted of the following:

	March 31, 2021		March 31, 2020
Bonus	$	95,795	$	10,000
Sales commissions		45,370		29,994
Sales and use tax		15,065		12,037
Marketing fees		15,330		10,511
Payroll taxes		93,857		22,712
Miscellaneous		16,685		10,823
Total other accrued liabilities	$	282,102	$	96,077

Schedule of stock-based compensation expense related to employee stock options

Stock-based compensation expense related to director and employee stock options under ASC 718 for fiscal years 2021 and 2020 was allocated as follows:

Years Ended	March 31, 2021		March 31, 2020
Cost of sales	$	3,669	$	2,811
Sales and marketing		4,871		3,317
General and administrative		22,632		22,671
Research and development		2,182		1,909
Stock-based compensation expense	$	33,354	$	30,708

Schedule of service performs electrical engineering activities for external entities

Service performs electrical engineering activities for external entities.

	Year Ended March 31, 2021
	Product			Service		Total
Net revenue	$	7,010,657		$	527,177	$	7,537,834
Cost of revenue		3,375,307			257,424		3,632,731
Gross profit		3,635,350			269,753		3,905,103
Operating income (loss)		(357,248	)		269,753		(61,641	)
Depreciation and amortization		88,955			—		88,955
Capital expenditures		117,420			—		117,420
Equipment and patents, net	$	479,085		$	—	$	479,085

Schedule of calculation of basic and diluted net income (loss) per share

The following table presents the calculation of basic and diluted net income (loss) per share:

Years Ended	March 31, 2021		March 31, 2020
Net income (loss)	$	584,734	$	(198,312	)
Weighted-average shares — basic		11,582,641		11,573,211
Effect of dilutive potential common shares		185,356		—
Weighted-average shares — basic and diluted		11,767,997		11,573,211
Net loss per share — basic and diluted	$	0.05	$	(0.02	)
Antidilutive equity units		850,644		998,000