CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (7,184)	$ (3,811)	$ (8,234)	$ (13,093)
Other comprehensive income (loss):
Change in unrealized gains (losses) on available-for-sale securities, net of tax	(3)		(3)
Foreign currency translation adjustments	66	(1,017)	263	(451)
Total other comprehensive income (loss)	63	(1,017)	260	(451)
Total comprehensive loss	$ (7,121)	$ (4,828)	$ (7,974)	$ (13,544)