Reconciliation of Actual Income Tax Expenses (Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Benefit for U.S federal income tax at statutory rate	$ (4,849)	$ (18,940)	$ (19,365)
Effect of foreign income taxes	(47)	124	630
Research and experimentation tax credit	(320)	(248)	(686)
State income taxes, net of federal income tax benefit	(23)		4
Nondeductible expenses	33	164	149
Resolution of prior years’ tax matters	(657)	2	2,400
Change in valuation allowance	(4,237)	20,087	7,715
Impact on deferred taxes due to change in tax rate	8,116	(6)	(124)
Difference in U.S. tax rate from assumed rate	511
Foreign income taxes	11	506
Disallowance of stock compensation adjustments in excess of book	895	1,074
Other items	(13)	(80)	(86)
Income tax expense	$ (580)	$ 2,683	$ (9,363)
Effective tax rate	2.90%	(5.00%)	16.90%