Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 1,466	$ (2,682)	$ 4,038	$ (2,704)
Other comprehensive income (loss):
Unrealized holding gains (losses) on available-for-sale securities, net of tax	13		57	(41)
Foreign currency translation adjustments	520	(2,231)	(798)	(394)
Other comprehensive income (loss)	533	(2,231)	(741)	(435)
Comprehensive income (loss)	$ 1,999	$ (4,913)	$ 3,297	$ (3,139)