Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Total revenue	$ 26,883	$ 24,344	$ 72,321	$ 69,261
Operating costs and expenses:
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Product costs	$ 4,443	$ 3,364	$ 11,415	$ 9,980
Research and development	13,324	13,321	37,401	38,362
Selling, general and administrative	7,416	5,939	21,092	16,764
Acquired intangible asset amortization	536	599	1,671	1,809
Contingent consideration expense (gain)		104		(248)
Total operating costs and expenses	25,719	23,327	71,579	66,667
Operating income	1,164	1,017	742	2,594
Other income (expense):
Investment income, net	124	269	584	850
Interest expense	(29)	(38)	(99)	(112)
Foreign exchange (loss) gain	(48)	(42)	(125)	99
Impairment loss on strategic investment			(479)
Other			1	9
Other income (expense)	47	189	(118)	846
Income before income taxes	1,211	1,206	624	3,440
Income tax benefit	1,248	260	3,445	598
Net income	$ 2,459	$ 1,466	$ 4,069	$ 4,038
Basic net income per share	$ 0.18	$ 0.11	$ 0.30	$ 0.30
Diluted net income per share	$ 0.18	$ 0.11	$ 0.30	$ 0.29
Weighted average number of shares outstanding:
Basic	13,601	13,394	13,577	13,384
Diluted	13,786	13,726	13,775	13,776
Product Sales [Member]
Revenue:
Total revenue	$ 11,987	$ 9,870	$ 33,731	$ 29,508
Royalties and License Fees [Member]
Revenue:
Total revenue	12,398	11,624	30,767	31,652
Research, Development and Other [Member]
Revenue:
Total revenue	$ 2,498	$ 2,850	$ 7,823	$ 8,101