Summary of Significant Accounting Policies and Select Balance Sheet Information - Amortized Cost, Unrealized Holding Gains (Losses) and Fair Value of Available for Sale Securities (Details) - USD ($)	Sep. 30, 2016	Sep. 30, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 22,019,000
Unrealized Losses	(65,000)
Fair Value	21,954,000	$ 0
Commercial paper and corporate bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	22,019,000
Unrealized Losses	(65,000)
Fair Value	$ 21,954,000