Stock-based Compensation and Equity Grants - Stock Options Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Number of Shares
Outstanding at beginning of period (in shares)	1,994	2,226
Granted (in shares)	217	400
Exercised or canceled (in shares)	(77)	(632)
Outstanding at end of period (in shares)	2,134	1,994	2,226
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 3.83	$ 1.40
Granted (in dollars per share)	6.33	5.94
Exercised or canceled (in dollars per share)	3.70	1.28
Outstanding at end of period (in dollars per share)	$ 4.31	$ 3.83	$ 1.40
Weighted Average Remaining Contractual Term
Options outstanding at the of period (in years)	6 years 3 months 18 days	6 years 4 months 24 days	5 years 9 months 18 days
Aggregate Intrinsic Value
Options outstanding at the end of period (in dollars)	$ 6,949	$ 8,489	$ 7,581