SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Allowance for sales returns
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Period	$ 751	$ 763	$ 788
Charged to Costs and Expenses	4,475	4,033	4,151
Deductions	4,458	4,045	4,176
Balance at End of Period	768	751	763
Allowance for doubtful accounts
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Period	333	471	864
Charged to Costs and Expenses	60	45	(250)
Deductions	109	183	143
Balance at End of Period	284	333	471
Allowance for deferred tax assets
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Period	1,881	1,981	1,653
Charged to Costs and Expenses	222	(100)	328
Balance at End of Period	$ 2,103	$ 1,881	$ 1,981