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
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Net income (loss)	$ 560	$ (3,191)
Weighted-average shares outstanding - basic (in shares)	40,615	38,247
Common stock equivalents (in shares)	1,213	0
Weighted-average shares outstanding - diluted (in shares)	41,828	38,247
Net income (loss) per share:
Basic (in dollars per share)	$ 0.01	$ (0.08)
Diluted (in dollars per share)	$ 0.01	$ (0.08)