Nature of Operations and Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Net loss	$ (5,736)	$ (607)
Weighted-average common shares and share equivalents outstanding - basic and diluted (in shares)	34,207	32,377
Net loss per share – basic and diluted (in dollars per share)	$ (0.17)	$ (0.02)