Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net income (loss)		$ 1,123	$ 7,592	$ (4,457)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		7,263	7,312	6,431
Stock-based compensation		5,453	5,077	4,807
Payment of contingent consideration obligations in excess of acquisition-date value		(608)	(2,041)
Contingent consideration (gain) expense			(161)	675
Acquired in-process research and development			890	7,888
Deferred taxes	[1]	(1,139)	(1,088)	(2,277)
Losses (gains) on strategic investments		479	(7)	(177)
Provision for bad debts		73	160	85
Noncash lease expense		246
Impairment losses on intangible assets			259
Unrealized foreign exchange gain				(148)
Other		5	(9)	45
Change in operating assets and liabilities
Accounts receivable and contract asset	[1]	3,461	(1,630)	(1,773)
Inventories		(1,377)	(543)	(513)
Prepaids and other		410	(2,131)	(1,584)
Accounts payable		(483)	(765)	155
Accrued liabilities		1,847	(2,187)	5,086
Income taxes	[1]	(1,558)	822	(842)
Deferred revenue	[1]	(1,185)	(3,512)	20,651
Net cash provided by operating activities		14,010	8,038	34,052
Investing Activities:
Purchases of property and equipment		(3,671)	(5,998)	(9,092)
Cash proceeds from sale of property and equipment			10
Purchases of available-for-sale securities		(59,917)	(44,973)	(81,536)
Sales and maturities of available-for-sale securities		54,522	61,458	71,951
Acquisition of in-process research and development (Note 11)			(750)	(5,000)
Cash received from strategic investments			7	177
Net cash (used in) provided by investing activities		(9,066)	9,754	(23,500)
Financing Activities:
Issuance of common stock		1,615	723	2,089
Payments for taxes related to net share settlement of equity awards		(2,534)	(2,688)	(4,557)
Payment of deferred financing costs		(137)
Payment of contingent consideration obligations		(2,592)	(9,064)	(925)
Payments for acquisition of in-process research and development (Note 11)		(1,000)
Net cash used in financing activities		(4,648)	(11,029)	(3,393)
Effect of exchange rate changes on cash		128	(70)	(25)
Net change in cash and cash equivalents		424	6,693	7,134
Cash and Cash Equivalents:
Beginning of year		30,361	23,668	16,534
End of year		30,785	30,361	23,668
Supplemental Information:
Cash paid for income taxes		30	193	914
Noncash financing and investing activities:
Acquisition of property and equipment and intangible assets, net of refundable credits in other current assets and liabilities		1,306	202	632
Right-of-use assets and property and equipment obtained in exchange for new operating lease liabilities		$ 1,181
Acquisition of in-process research and development in other long-term liabilities			140	2,888
Accrual of employee taxes on common stock exercises			$ 104	130
Acquisition of property and equipment in long-term deferred rent				$ 1,200

[1] For the fiscal year ended September 30, 2018, amounts presented are net of impact from adoption of ASC Topic 606.