Fair Value of Company's Short-term Investments, Contingemt Earn-Out Liability and Foreign Currency Forward Contracts (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent Consideration	$ (10,912)	$ (9,940)
Total	(10,934)	(9,944)
Significant Other Observable (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	(22)	(4)
Significant Unobservable (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent Consideration	(10,912)	(9,940)
Total	(10,912)	(9,940)
Foreign Currency Forward Contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign Currency Forward Contract	(22)	(4)
Foreign Currency Forward Contracts | Significant Other Observable (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign Currency Forward Contract	$ (22)	$ (4)