Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (19,242)	$ (146)
Other comprehensive income (loss):
Change in unrealized gains on available-for-sale securities, net of tax		82
Foreign currency translation adjustments	(941)	(220)
Other comprehensive loss	(941)	(138)
Total comprehensive loss	$ (20,183)	$ (284)