Balance Sheets - USD ($)	Mar. 31, 2018	Mar. 31, 2017
ASSETS
Cash and cash equivalents	$ 4,755,082	$ 8,199,364
Marketable securities, short-term	20,765,809	19,591,833
Accounts receivable, net of allowance for uncollectible accounts of $15,000	2,888,779	3,436,802
Inventories	3,650,439	3,358,298
Prepaid expenses and other assets	635,160	607,283
Total current assets	32,695,269	35,193,580
Fixed assets
Machinery and equipment	9,395,987	9,007,455
Leasehold improvements	1,749,284	1,644,419
	11,145,271	10,651,874
Less accumulated depreciation and amortization	9,819,888	9,238,626
Net fixed assets	1,325,383	1,413,248
Deferred tax assets	572,655	357,055
Marketable securities, long-term	52,838,158	56,810,923
Total assets	87,431,465	93,774,806
LIABILITIES AND SHAREHOLDERS’ EQUITY
Accounts payable	414,970	376,275
Accrued payroll and other	574,755	576,313
Deferred revenue		142,733
Total current liabilities	989,725	1,095,321
Shareholders’ equity
Common stock, $0.01 par value, 6,000,000 shares authorized; 4,842,010 issued and outstanding as of March 31, 2018 and 4,841,010 issued and outstanding as of March 31, 2017	48,420	48,410
Additional paid-in capital	19,599,298	19,507,348
Accumulated other comprehensive loss	(915,635)	(38,298)
Retained earnings	67,709,657	73,162,025
Total shareholders’ equity	86,441,740	92,679,485
Total liabilities and shareholders’ equity	$ 87,431,465	$ 93,774,806