Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income (loss)	$ 2,621	$ 1,335	$ (2,305)	$ 5,023
Denominator:
Denominator for basic net income (loss) per common share — weighted average shares outstanding	27,177,000	26,522,000	27,002,000	26,390,000
Effect of dilutive securities:
Stock options and restricted stock units	587,000	434,000	0	720,000
Denominator for diluted net income (loss) per common share — adjusted weighted average shares	27,764,000	26,956,000	27,002,000	27,110,000
Basic net income (loss) per common share:
Net income (loss), basic (USD per share)	$ 0.10	$ 0.05	$ (0.09)	$ 0.19
Diluted net income (loss) per common share
Net income (loss), diluted (USD per share)	$ 0.09	$ 0.05	$ (0.09)	$ 0.19
Potentially dilutive securities excluded from computation of earnings per share	770,178	1,910,081	977,828	1,169,422
Excluded incremental common shares related to common stock options and restricted stock units			440,002