Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Total revenue	$ 23,873	$ 26,883	$ 81,165	$ 72,321
Operating costs and expenses:
Type of Cost, Good or Service [Extensible List]	Product Sales [Member]	Product Sales [Member]	Product Sales [Member]	Product Sales [Member]
Product costs	$ 5,105	$ 4,443	$ 13,018	$ 11,415
Research and development	12,246	13,324	36,003	37,401
Selling, general and administrative	7,885	7,416	22,815	21,092
Acquired intangible asset amortization	560	536	1,676	1,671
Acquisition transaction, integration and other costs	461		461
Total operating costs and expenses	26,257	25,719	73,973	71,579
Operating (loss) income	(2,384)	1,164	7,192	742
Other (expense) income:
Investment income, net	26	124	95	584
Interest expense	(59)	(29)	(178)	(99)
Foreign exchange loss	(94)	(48)	(201)	(125)
Impairment loss on strategic investment and other				(478)
Other (expense) income	(127)	47	(284)	(118)
(Loss) income before income taxes	(2,511)	1,211	6,908	624
Income tax (provision) benefit	(776)	1,248	(2,382)	3,445
Net (loss) income	$ (3,287)	$ 2,459	$ 4,526	$ 4,069
Basic net (loss) income per share	$ (0.24)	$ 0.18	$ 0.33	$ 0.30
Diluted net (loss) income per share	$ (0.24)	$ 0.18	$ 0.32	$ 0.30
Weighted average number of shares outstanding:
Basic	13,837	13,601	13,740	13,577
Diluted	13,837	13,786	13,959	13,775
Product Sales [Member]
Revenue:
Total revenue	$ 12,084	$ 11,987	$ 33,969	$ 33,731
Royalties and License Fees [Member]
Revenue:
Total revenue	8,796	12,398	38,182	30,767
Research, Development and Other [Member]
Revenue:
Total revenue	$ 2,993	$ 2,498	$ 9,014	$ 7,823