Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Accounts receivable:
Allowance for doubtful accounts	$ 95	$ 22
Shareholders’ equity:
Common stock, par value (in usd per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	34,368,000	33,938,000
Common stock, shares outstanding (in shares)	27,458,000	27,028,000
Treasury stock, shares held (in shares)	6,910,000	6,910,000