Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Revenue:
Royalties and license fees	$ 7,383	$ 7,329	$ 14,658	$ 14,794
Product sales	5,651	5,165	11,498	10,565
Research and development	1,381	1,110	2,464	2,128
Total revenue	14,415	13,604	28,620	27,487
Operating costs and expenses:
Product costs	1,955	1,696	3,857	3,700
Research and development	4,403	4,134	7,979	7,833
Selling, general and administrative	4,125	4,294	7,818	8,145
Total operating costs and expenses	10,483	10,124	19,654	19,678
Operating income	3,932	3,480	8,966	7,809
Other income:
Investment income, net	56	66	113	152
Gain on sale of strategic investment				681
Other income, net	543	125	536	125
Other income, net	599	191	649	958
Income before income taxes	4,531	3,671	9,615	8,767
Income tax provision	(1,480)	(1,212)	(2,950)	(2,678)
Net income	$ 3,051	$ 2,459	$ 6,665	$ 6,089
Basic net income per share	$ 0.24	$ 0.18	$ 0.51	$ 0.45
Diluted net income per share	$ 0.23	$ 0.18	$ 0.50	$ 0.44
Weighted average number of shares outstanding:
Basic	12,944	13,538	13,092	13,658
Diluted	13,207	13,824	13,365	13,925