Reconciliation of Actual Income Tax Expenses (Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Provision (benefit) for U.S federal income tax at statutory rate	$ (19,365)	$ (17,442)	$ 18,740
Effect of foreign income taxes	630	249	(629)
Manufacturers’/producers’ deduction			(1,496)
Research and experimentation tax credit	(686)	(400)	(208)
State income taxes, net of federal income tax benefit	4	2	45
Nondeductible expenses	149	488	205
Resolution of prior years’ tax matters		96	20
Adjustment to prior year manufacturers’/producers’ deduction	1,450
Correction of prior year income tax benefit	950
Contingency for uncertainty in income taxes		(121)
Change in valuation allowance	7,715
Other items	(210)	(65)	(45)
Income tax expense	$ (9,363)	$ (17,193)	$ 16,632
Effective tax rate	(14.10%)	(34.50%)	31.10%