Summary of Significant Accounting Policies and Select Balance Sheet Information - Denominator for Computation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income (loss) available to common shareholders	$ 1,123	$ 7,592	$ (4,457)
Basic weighted average shares outstanding	13,552	13,389	13,157
Dilutive effect of outstanding stock options, non-vested restricted stock, and non-vested restricted stock units	260	390
Diluted weighted average shares outstanding	13,812	13,779	13,157