Condensed Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows (used in) operating activities:
Net (loss)	$ (6,842)	$ (139,305)
Adjustments to reconcile net (loss) to net cash (used in) operating activities:
Depreciation and amortization	26,783	25,784
Stock-based compensation expense related to stock options	8,340	7,534
(Recovery from) provision for doubtful accounts, net change	(25,000)	(13,000)
Provision for (recovery from) for inventory obsolescence, net change	(49,000)	14,000
Change in operating assets and liabilities:
Right of use asset, net	(4,687)	20,437
Accounts receivable	(91,601)	97,239
Inventories	(96,813)	(96,456)
Prepaid expenses and other assets	44,049	(39,757)
Accounts payable	131,938	(52,175)
Accrued compensation and other accrued liabilities	(65,216)	11,294
Net cash (used in) operating activities	(128,049)	(164,405)
Cash flows (used in) investing activities:
Acquisition of property and equipment	(6,720)	0
Patent costs	(7,561)	(4,334)
Net cash (used in) investing activities	(14,281)	(4,334)
Cash flows from (used in) financing activities:
(Paydown of) borrowings from credit facility, net change	0	(186,541)
(Paydown of) secured notes	(3,340)	0
Unsecured promissory note	0	598,567
Net cash generated by (used in) financing activities	(3,340)	412,026
Net (decrease) increase in cash	(145,670)	243,287
Cash, beginning of fiscal year	1,474,339	385,132
Cash, end of fiscal year	1,328,669	628,419
Supplemental disclosures of cash flow information:
Cash paid during the year for interest	$ 1,806	$ 17,483