Reconciliation of Actual Income Tax Expenses (Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Benefit for U.S federal income tax at statutory rate	$ (18,940)	$ (19,365)	$ (17,442)
Effect of foreign income taxes	124	630	249
Research and experimentation tax credit	(248)	(686)	(400)
State income taxes, net of federal income tax benefit		4	2
Nondeductible expenses	164	149	488
Resolution of prior years’ tax matters	2	2,400	96
Contingency for uncertainty in income taxes			(121)
Change in valuation allowance	20,087	7,715
Foreign income taxes - tax credits	506
Disallowance of stock compensation adjustments in excess of book	1,074
Other items	(86)	(210)	(65)
Income tax expense	$ 2,683	$ (9,363)	$ (17,193)
Effective tax rate	(5.00%)	(16.90%)	34.50%