Statements of Income (Unaudited) - USD ($)	3 Months Ended						9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Revenue	$ 6,290,809			$ 6,533,362			$ 20,267,433	$ 15,503,409
Cost of sales	1,385,006			1,075,048			4,698,720	2,852,757
Gross profit	4,905,803			5,458,314			15,568,713	12,650,652
Expenses
Research and development	596,492			702,216			2,112,630	2,399,164
Selling, general, and administrative	272,159			311,356			1,221,893	1,024,549
Total expenses	868,651			1,013,572			3,334,523	3,423,713
Income from operations	4,037,152			4,444,742			12,234,190	9,226,939
Interest income	283,940			365,498			868,519	1,166,102
Income before taxes	4,321,092			4,810,240			13,102,709	10,393,041
Provision for income taxes	855,685			884,531			2,411,228	1,833,127
Net income	$ 3,465,407	$ 3,646,507	$ 3,579,566	$ 3,925,709	$ 2,222,340	$ 2,411,865	$ 10,691,481	$ 8,559,914
Net income per share – basic (in dollars per share)	$ 0.72			$ 0.81			$ 2.21	$ 1.77
Net income per share – diluted (in dollars per share)	0.72			0.81			2.21	1.77
Cash dividends declared per common share (in dollars per share)	$ 1.00			$ 1.00			$ 3.00	$ 3.00
Weighted average shares outstanding
Weighted average common shares outstanding – basic (in shares)	4,833,604			4,833,232			4,833,356	4,834,324
Diluted (in shares)	4,835,770			4,833,261			4,835,781	4,834,411
Product [Member]
Revenue	$ 5,916,790			$ 6,332,349			$ 19,500,567	$ 14,850,157
Contract Research and Development [Member]
Revenue	$ 374,019			$ 201,013			$ 766,866	$ 653,252