Restructuring Plans - Schedule of Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Restructuring And Related Activities [Abstract]
Balance at beginning of the year				$ 102	$ 40
Severance expense, net of adjustments	$ 15	$ 71	$ 217	86	217	$ 1,110
Cash payments				(171)	(155)
Balance at the end of the year	$ 17			$ 17	$ 102	$ 40