Basis of Presentation and Significant Accounting Policies - Summary of Option Activity (Detail) - $ / shares	9 Months Ended	12 Months Ended
	Jun. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding Beginning Balance (in shares)	1,654,429
Options, Granted (in shares)	190,750
Options, Exercised (in shares)	(21,000)
Options, Forfeited (in shares)	(61,283)
Options, Outstanding Ending Balance (in shares)	1,762,896	1,654,429
Options, Exercisable Ending Balance (in shares)	1,400,497
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Outstanding Beginning Balance (in usd per share)	$ 5.62
Weighted Average Exercise Price, Granted (in usd per share)	1.29
Weighted Average Exercise Price, Exercised (in usd per share)	0.88
Weighted Average Exercise Price, Forfeited (in usd per share)	3.98
Weighted Average Exercise Price, Outstanding Ending Balance (in usd per share)	5.26	$ 5.62
Weighted Average Exercise Price, Exercisable Ending Balance	$ 6.27
Weighted Average Remaining Contractual Period in Years, Outstanding Ending Balance	4 years 7 months 24 days	4 years 10 months 24 days
Weighted Average Remaining Contractual Period in Years, Granted	9 years 4 months 24 days
Weighted Average Remaining Contractual Period in Years, Exercised	8 years 4 months 24 days
Weighted Average Remaining Contractual Period in Years, Forfeited	4 years 5 months 24 days
Weighted Average Remaining Contractual Period in Years, Exercisable Ending Balance	3 years 8 months 24 days