Summary of Significant Accounting Policies and Select Balance Sheet Information - Impact of Adoption of ASC Topic 606 on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Assets
Contract assets - royalties and license fees	$ 8,210
Deferred income taxes	6,176		$ 6,304
Income tax receivable	558		1,152
Liabilities and Stockholders' Equity
Deferred revenue, current portion			9,646
Deferred revenue, less current portion			11,247
Retained earnings	110,705		$ 97,615
Adoption of ASC Topic 606 [Member]
Assets
Contract assets - royalties and license fees		$ 6,904
Deferred income taxes		5,089
Income tax receivable		762
Liabilities and Stockholders' Equity
Deferred revenue, current portion		9,628
Deferred revenue, less current portion		11,066
Retained earnings		103,113
Adjustments | Adoption of ASC Topic 606 [Member]
Assets
Contract assets - royalties and license fees		6,904
Deferred income taxes	1,200	(1,215)
Income tax receivable	$ 400	(390)
Liabilities and Stockholders' Equity
Deferred revenue, current portion		(18)
Deferred revenue, less current portion		(181)
Retained earnings		$ 5,498