Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (4,083)	$ 8,087	$ (6,895)	$ 7,813
Other comprehensive (loss) income:
Net changes related to available-for-sale securities, net of tax	(6)	(7)	(11)	(7)
Foreign currency translation adjustments	(1,503)	(1,768)	(3,150)	64
Other comprehensive (loss) income	(1,509)	(1,775)	(3,161)	57
Comprehensive (loss) income	$ (5,592)	$ 6,312	$ (10,056)	$ 7,870