Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 22,616	$ 22,241
Operating costs and expenses:
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Product costs	$ 3,203	$ 3,523
Research and development	12,142	11,486
Selling, general and administrative	6,943	5,949
Acquired intangible asset amortization	594	606
Contingent consideration gain		(35)
Total operating costs and expenses	22,882	21,529
Operating (loss) income	(266)	712
Other income:
Investment income, net	250	316
Interest expense	(40)	(37)
Foreign exchange (loss) gain	(47)	136
Other	1	7
Other income	164	422
(Loss) income before income taxes	(102)	1,134
Income tax benefit	250	176
Net income	$ 148	$ 1,310
Basic net income per share:	$ 0.01	$ 0.10
Diluted net income per share:	$ 0.01	$ 0.09
Weighted average number of shares outstanding:
Basic	13,469	13,367
Diluted	13,769	13,827
Product Sales [Member]
Revenue:
Total revenue	$ 9,974	$ 9,751
Royalties and License Fees [Member]
Revenue:
Total revenue	10,148	10,096
Research, Development and Other [Member]
Revenue:
Total revenue	$ 2,494	$ 2,394