Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating lease cost	$ 598	$ 571	$ 1,835	$ 1,779
Less: sublease income	(175)	(156)	(532)	(393)
Variable lease cost	117	86	334	265
Short-term lease cost	365	148	853	496
Total lease cost	$ 905	$ 649	$ 2,490	$ 2,147