Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Total revenue	$ 22,297	$ 22,616
Operating costs and expenses:
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Product costs	$ 3,743	$ 3,203
Research and development	10,882	12,142
Selling, general and administrative	7,023	6,943
Acquired intangible asset amortization	556	594
Total operating costs and expenses	22,204	22,882
Operating income (loss)	93	(266)
Other (expense) income:
Investment income, net	41	250
Interest expense	(60)	(40)
Foreign exchange loss	(180)	(47)
Other		1
Other (expense) income	(199)	164
Loss before income taxes	(106)	(102)
Income tax (provision) benefit	(168)	250
Net (loss) income	$ (274)	$ 148
Basic net (loss) income per share	$ (0.02)	$ 0.01
Diluted net (loss) income per share	$ (0.02)	$ 0.01
Weighted average number of shares outstanding:
Basic	13,668	13,469
Diluted	13,668	13,769
Product Sales [Member]
Revenue:
Total revenue	$ 10,102	$ 9,974
Royalties and License Fees [Member]
Revenue:
Total revenue	9,334	10,148
Research, Development and Other [Member]
Revenue:
Total revenue	$ 2,861	$ 2,494