Stock-Based Compensation - Stock option activity (Details) - Stock options - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Number of Shares
Balance, Beginning (in shares)	3,762,143	1,389,999
Granted (in shares)	12,461,645	2,641,621
Forfeited or expired (in shares)	(113,773)	(269,477)
Balance, Ending (in shares)	16,110,015	3,762,143
Vested and exercisable (in shares)	3,683,874
Vested and expected to vest (in shares)	16,110,015
Weighted Average Exercise Price
Balance, Beginning (in dollars per share)	$ 2.01	$ 3.46
Granted (in dollars per share)	1.29	1.33
Forfeited or expired (in dollars per share)		2.78
Forfeited (in dollars per share)	0.76
Balance, Ending (in dollars per share)	1.46	$ 2.01
Vested and exercisable (in dollars per share)	1.65
Vested and expected to vest (in dollars per share)	$ 1.46
Other option information
Balance-Remaining contractual term	9 years
Vested and exercisable-Remaining contractual term	8 years 6 months
Vested and expected to vest-Remaining contractual term	9 years
Aggregate intrinsic value, Vest and expected	$ 14,303,576
Aggregate intrinsic value, Vest and exercisable	$ 3,218,406