Selected Balance Sheet Data (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Accounts receivable, net:
Accounts receivable	$ 32,861	$ 31,365
Less allowance for doubtful accounts	476	341
Less reserve for future returns and pricing adjustments	2,093	2,169
Accounts receivable, net	30,292	28,855
Inventories:
Raw materials	24,622	24,050
Work in process	22	484
Finished goods	6,475	5,704
Inventories	$ 31,119	$ 30,238