Balance Sheets (Current Period Unaudited) - USD ($)		Dec. 31, 2020	Mar. 31, 2020
Current assets
Cash and cash equivalents		$ 13,988,308	$ 8,065,594	[1]
Marketable securities, short-term		11,115,094	19,084,814	[1]
Accounts receivable, net of allowance for uncollectible accounts of $15,000		3,161,308	2,694,018	[1]
Inventories		3,842,477	3,884,450	[1]
Prepaid expenses and other assets		570,018	655,835	[1]
Total current assets		32,677,205	34,384,711	[1]
Fixed assets
Machinery and equipment		9,280,062	9,280,062	[1]
Leasehold improvements		1,810,872	1,797,245	[1]
Property, Plant and Equipment, Gross, Ending Balance		11,090,934	11,077,307	[1]
Less accumulated depreciation and amortization		10,724,866	10,494,840	[1]
Net fixed assets		366,068	582,467	[1]
Deferred tax assets			108,119	[1]
Marketable securities, long-term		40,656,967	43,606,495	[1]
Right-of-use asset – operating lease		720,618	816,358	[1]
Total assets		74,420,858	79,498,150	[1]
Current liabilities
Accounts payable		136,673	186,993	[1]
Accrued payroll and other		505,428	482,074	[1]
Operating lease		106,843	127,134	[1]
Total current liabilities		748,944	796,201	[1]
Deferred tax liabilities		89,420		[1]
Operating lease		613,775	706,600	[1]
Total liabilities	[1]	1,452,139	1,502,801
Shareholders’ equity
Common stock, $0.01 par value, 6,000,000 shares authorized; 4,833,232 issued and outstanding as of December 31, 2020 and 4,835,038 as of March 31, 2020		48,332	48,350	[1]
Additional paid-in capital		19,333,852	19,383,956	[1]
Accumulated other comprehensive income		1,483,409	516,523	[1]
Retained earnings		52,103,126	58,046,520	[1]
Total shareholders’ equity		72,968,719	77,995,349	[1]
Total liabilities and shareholders’ equity		$ 74,420,858	$ 79,498,150	[1]

[1] The March 31, 2020 Balance Sheet is derived from the audited financial statements contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2020.