Restructuring and Other Costs, Net - Schedule of Accrual Activity Relating to Restructuring Reserves (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Restructuring Cost And Reserve [Line Items]
Balance as of September 30, 2023			$ 1,582
Restructuring and other costs, net	$ 4,551	$ 5,714	5,256	$ 9,903
Non-cash adjustments			(651)
Cash payments			(2,918)
Effect of foreign currency translation			4
Balance at March 31, 2024	3,273		3,273
Personnel
Restructuring Cost And Reserve [Line Items]
Balance as of September 30, 2023			549
Restructuring and other costs, net	4,404	3,371	4,519	6,420
Cash payments			(2,544)
Effect of foreign currency translation			4
Balance at March 31, 2024	2,528		2,528
Facilities
Restructuring Cost And Reserve [Line Items]
Balance as of September 30, 2023			1,033
Restructuring and other costs, net	147	150	292	343
Non-cash adjustments			(351)
Cash payments			(261)
Balance at March 31, 2024	713		713
Restructuring Subtotal
Restructuring Cost And Reserve [Line Items]
Balance as of September 30, 2023			1,582
Restructuring and other costs, net	4,551	3,521	4,811	6,763
Non-cash adjustments			(351)
Cash payments			(2,805)
Effect of foreign currency translation			4
Balance at March 31, 2024	3,241		3,241
Other
Restructuring Cost And Reserve [Line Items]
Restructuring and other costs, net		$ 2,193	445	$ 3,140
Non-cash adjustments			(300)
Cash payments			(113)
Balance at March 31, 2024	$ 32		$ 32