Statements of Income (Unaudited) - USD ($)	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Revenue	$ 7,336,407	$ 7,153,163
Cost of sales	1,651,847	1,769,581
Gross profit	5,684,560	5,383,582
Expenses
Research and development	601,918	808,142
Selling, general, and administrative	371,320	466,618
Total expenses	973,238	1,274,760
Income from operations	4,711,322	4,108,822
Interest income	283,059	289,720
Income before taxes	4,994,381	4,398,542
Provision for income taxes	854,265	818,976
Net income	$ 4,140,116	$ 3,579,566
Net income per share – basic (in dollars per share)	$ 0.86	$ 0.74
Net income per share – diluted (in dollars per share)	0.86	0.74
Cash dividends declared per common share (in dollars per share)	$ 1.00	$ 1.00
Weighted average shares outstanding
Weighted average common shares outstanding – basic (in shares)	4,830,826	4,833,232
Diluted (in shares)	4,830,871	4,836,821
Product [Member]
Revenue	$ 7,072,961	$ 6,953,766
Contract Research and Development [Member]
Revenue	$ 263,446	$ 199,397