Statements of Income (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Revenue
Product sales	$ 5,394,758	$ 6,686,451	$ 17,975,331	$ 19,290,839
Contract research and development	763,768	1,277,057	2,995,590	3,723,123
Total revenue	6,158,526	7,963,508	20,970,921	23,013,962
Cost of sales	2,174,878	2,461,798	7,048,396	7,142,528
Gross profit	3,983,648	5,501,710	13,922,525	15,871,434
Expenses
Selling, general , and administrative	520,044	638,223	1,742,721	1,901,156
Research and development	718,688	330,681	1,825,159	982,217
Total expenses	1,238,732	968,904	3,567,880	2,883,373
Income from operations	2,744,916	4,532,806	10,354,645	12,988,061
Interest income	591,694	512,203	1,754,586	1,485,664
Income before taxes	3,336,610	5,045,009	12,109,231	14,473,725
Provision for income taxes	1,047,519	1,661,090	3,825,819	4,782,699
Net income	$ 2,289,091	$ 3,383,919	$ 8,283,412	$ 9,691,026
Net income per share - basic	$ 0.48	$ 0.71	$ 1.73	$ 2.06
Net income per share - diluted	$ 0.47	$ 0.70	$ 1.71	$ 2.00
Weighted average shares outstanding
Basic	4,807,859	4,743,643	4,786,790	4,714,989
Diluted	4,873,429	4,866,617	4,852,360	4,837,963