Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue
Product sales	$ 6,387,080	$ 6,814,384	$ 13,269,753	$ 12,665,598
Contract research and development	609,154	488,155	1,334,147	1,344,713
Total revenue	6,996,234	7,302,539	14,603,900	14,010,311
Cost of sales	1,353,169	1,740,814	3,151,535	3,125,992
Gross profit	5,643,065	5,561,725	11,452,365	10,884,319
Expenses
Selling, general, and administrative	348,363	343,688	747,724	733,603
Research and development	1,030,504	768,188	1,936,229	1,526,556
Total expenses	1,378,867	1,111,876	2,683,953	2,260,159
Income from operations	4,264,198	4,449,849	8,768,412	8,624,160
Interest income	387,860	430,983	749,638	868,717
Income before taxes	4,652,058	4,880,832	9,518,050	9,492,877
Provision for income taxes	1,491,023	1,575,635	3,059,400	3,055,135
Net income	$ 3,161,035	$ 3,305,197	$ 6,458,650	$ 6,437,742
Net income per share – basic (in dollars per share)	$ 0.65	$ 0.68	$ 1.33	$ 1.33
Net income per share – diluted (in dollars per share)	0.65	0.68	1.33	1.33
Cash dividends declared per common share (in dollars per share)	$ 1	$ 1	$ 2	$ 2
Weighted average shares outstanding
Basic (in shares)	4,841,010	4,835,564	4,841,010	4,835,289
Diluted (in shares)	4,845,632	4,837,819	4,845,907	4,837,293