Income and other Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Income tax benefit computed at U.S. federal statutory rate									$ 2,841	$ 896	$ (1,518)
State tax expense benefit, net of U.S. federal effect									414	(41)	(356)
Foreign tax rate differential									229	(94)	(269)
Effect due to change in tax rate									2,528	626	0
Windfall from stock based compensation									(150)	0	0
Other									126	(57)	108
State net operating loss carryforward adjustment									933	685	0
Change in valuation allowance									(6,758)	(2,001)	(156)
Income tax expense (benefit)	$ 32	$ 19	$ (8)	$ 120	$ (8)	$ 175	$ (155)	$ 2	$ 163	$ 14	$ (2,191)	$ (24,600)
Effective tax rate									1.90%	0.50%	49.10%