Leases - Summary of Operating Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Assets:
Operating lease assets, net	$ 3,732	$ 5,217
Liabilities:
Current operating lease liabilities	1,640	2,352
Long-term operating lease liabilities	2,554	3,434
Total lease liabilities	$ 4,194	$ 5,786