Statements of Income (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenue
Product sales	$ 5,557,299	$ 6,410,512	$ 12,580,573	$ 12,604,388
Contract research and development	1,041,334	1,398,648	2,231,822	2,446,066
Total revenue	6,598,633	7,809,160	14,812,395	15,050,454
Cost of sales	2,277,926	2,604,926	4,873,518	4,680,730
Gross profit	4,320,707	5,204,234	9,938,877	10,369,724
Expenses
Selling, general , and administrative	606,847	634,547	1,222,677	1,262,933
Research and development	611,595	309,873	1,106,471	651,536
Total expenses	1,218,442	944,420	2,329,148	1,914,469
Income from operations	3,102,265	4,259,814	7,609,729	8,455,255
Interest income	597,363	497,731	1,162,892	973,461
Income before taxes	3,699,628	4,757,545	8,772,621	9,428,716
Provision for income taxes	1,144,535	1,551,535	2,778,300	3,121,609
Net income	$ 2,555,093	$ 3,206,010	$ 5,994,321	$ 6,307,107
Net income per share - basic	$ 0.53	$ 0.68	$ 1.26	$ 1.34
Net income per share - diluted	$ 0.52	$ 0.66	$ 1.22	$ 1.30
Weighted average shares outstanding
Basic	4,776,198	4,700,583	4,776,198	4,700,583
Diluted	4,896,525	4,860,237	4,896,525	4,860,237