Stock-based Compensation, Equity Grants, and Warrants - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2020	Sep. 30, 2019
Number of Shares
Outstanding at the beginning of the period (in shares)	2,134
Granted (in shares)	250
Exercised (in shares)	(505)
Outstanding at the end of the period (in shares)	1,879	2,134
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 4.36
Granted (in dollars per share)	4.17
Exercised (in dollars per share)	1.04
Outstanding at the end of the period (in dollars per share)	$ 4.60	$ 4.36
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term	6 years 7 months 24 days	5 years 10 months 24 days
Aggregate Intrinsic Value
Outstanding at the beginning of the period (in dollars)	$ 4,815
Outstanding at the end of the period (in dollars)	$ 2,878	$ 4,815