Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 531	$ 668
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	32,109,731	31,503,349
Common stock, shares outstanding (in shares)	32,109,731	31,503,349