Nature of Operations and Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Net income	$ 2,985	$ 1,348	$ 6,171	$ 2,816
Weighted-average shares outstanding - basic (in shares)	43,773	41,483	43,145	41,251
Common stock equivalents (in shares)	1,421	945	1,501	988
Weighted-average shares outstanding - diluted (in shares)	45,194	42,428	44,646	42,239
Net income per share:
Basic (in dollars per share)	$ 0.07	$ 0.03	$ 0.14	$ 0.07
Diluted (in dollars per share)	$ 0.07	$ 0.03	$ 0.14	$ 0.07