Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue
Revenue	$ 10,717,824	$ 6,823,462	$ 18,054,231	$ 13,976,625
Cost of sales	2,402,781	1,544,134	4,054,628	3,313,715
Gross profit	8,315,043	5,279,328	13,999,603	10,662,910
Expenses
Research and development	669,978	707,997	1,271,896	1,516,139
Selling, general, and administrative	435,625	483,116	806,946	949,734
Total expenses	1,105,603	1,191,113	2,078,842	2,465,873
Income from operations	7,209,440	4,088,215	11,920,761	8,197,037
Interest income	351,375	294,858	634,436	584,578
Income before taxes	7,560,815	4,383,073	12,555,197	8,781,615
Provision for income taxes	1,470,442	736,566	2,324,707	1,555,542
Net income	$ 6,090,373	$ 3,646,507	$ 10,230,490	$ 7,226,073
Net income per share – basic (in dollars per share)	$ 1.26	$ 0.75	$ 2.12	$ 1.50
Net income per share – diluted (in dollars per share)	1.26	0.75	2.12	1.49
Cash dividends declared per common share (in dollars per share)	$ 1.00	$ 1.00	$ 2.00	$ 2.00
Weighted average shares outstanding
Basic (in shares)	4,830,826	4,833,232	4,830,826	4,833,232
Diluted (in shares)	4,830,956	4,836,603	4,830,927	4,836,621
Product [Member]
Revenue
Revenue	$ 10,514,539	$ 6,630,012	$ 17,587,500	$ 13,583,778
Contract Research and Development [Member]
Revenue
Revenue	$ 203,285	$ 193,450	$ 466,731	$ 392,847