UNAUDITED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Current assets
Allowance for doubtful accounts	$ 1,260	$ 1,224
Stockholders' equity
Common stock: authorized (in shares)	200,000,000	200,000,000
Common stock: par value (in dollars per share)	$ 0.001	$ 0.001
Common stock: issued (in shares)	33,797,792	33,489,181
Treasury stock at cost, shares (in shares)	9,725,587	9,041,678