Nature of Operations and Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounting Policies [Abstract]
Net income (loss)	$ 1,348	$ (99)	$ 2,816	$ (4,006)
Weighted-average shares outstanding - basic (in shares)	41,483	39,936	41,251	39,034
Common stock equivalents (in shares)	945	0	988	0
Weighted-average shares outstanding - diluted (in shares)	42,428	39,936	42,239	39,034
Net income (loss) per share:
Basic (in dollars per share)	$ 0.03	$ (0.00)	$ 0.07	$ (0.10)
Diluted (in dollars per share)	$ 0.03	$ (0.00)	$ 0.07	$ (0.10)