Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Statement of Cash Flows [Abstract]
Net income	$ 575,501	$ 110,980
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Deferred income taxes	153,114	61,890
Depreciation and amortization	31,381	29,540
Amortization of right of use assets	55,300	52,450
Provision for inventory obsolescence	0	10,000
Non-cash stock-based compensation	6,168	5,276
Changes in assets and liabilities:
(Increase) decrease in accounts receivable	615,045	(397,653)
Decrease (increase) in inventories	386,646	(401,204)
Decrease (increase) in prepaid expenses & other assets	3,514	93,873
(Decrease) in accounts payable and other accrued liabilities	(555,716)	(90,872)
(Decrease) increase in accrued payroll, vacation pay and payroll taxes	84,842	(72,689)
(Decrease) increase in deferred revenues	1,129	(70,827)
Decrease in operating lease liabilities	(55,300)	(52,450)
Increase in accrued legal damages	51,920	75,144
Net cash provided by (used in) operating activities	1,353,544	(646,542)
Cash flows from investing activities:
Purchases of equipment	0	(15,386)
Net cash used in investing activities	0	(15,386)
Cash flows from financing activities:
Proceeds from SBA PPP Loan		722,577
Payment of dividends	(80,000)	0
Repayment of finance lease obligations	0	(49)
Net cash (used in) provided by financing activities	(80,000)	722,528
Net increase in cash and restricted cash	1,273,544	60,600
	5,496,325	5,134,739
Taxes paid	0	4,962
	6,769,869	5,195,339
Cash	3,485,275	3,126,195
Restricted cash	2,011,050	2,008,544
Cash	4,758,819	3,185,796
Restricted cash	$ 2,011,050	$ 2,009,543