Stock-based Compensation and Equity Grants - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Jun. 30, 2021	Sep. 30, 2020
Number of Shares
Options outstanding, September 30, 2020 (in shares)	2,129,000
Exercised (in shares)	(63,000)
Granted (in shares)	245,000
Cancelled (in shares)	(35,000)
Options outstanding, June 30, 2021 (in shares)	2,276,000	2,129,000
Weighted Average Exercise Price
Options outstanding, September 30, 2020 (in dollars per share)	$ 6.14
Exercised (in dollars per share)	3.62
Granted (in dollars per share)	10.04
Cancelled (in dollars per share)	7.36
Options outstanding, June 30, 2021 (in dollars per share)	$ 0	$ 6.14
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term	7 years 4 months 24 days	7 years 4 months 24 days
Aggregate Intrinsic Value
Options outstanding at September 30, 2020	$ 6,593
Options outstanding at June 30, 2021	$ 15,385	$ 6,593