Income Taxes - Schedule Of Tax Effects To Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Net operating loss carry-forwards	$ 54,842	$ 12,269
Accrued compensation and benefits	13,162	13,478
Stock-based compensation	13,010	7,144
Deferred revenue	40,577	35,247
Lease liabilities	19,656	17,313
Other accruals and reserves	17,384	15,786
Tax credit carryforwards	15,807	13,783
Depreciation	620	592
Total deferred tax assets before deferred liabilities	175,058	115,612
Valuation allowance	(32,587)	(23,495)
Deferred tax assets, net of valuation allowance	142,471	92,117
Purchased intangibles	(46,491)	(10,560)
Depreciation	(34,757)	(39,910)
Deferred Tax Liabilities, Deferred Expense, Other Capitalized Costs	(11,924)	(10,656)
Deferred Tax Liabilities, Deferred Expense, Reserves and Accruals	(4,728)	(3,603)
Total deferred tax liabilities	(97,900)	(64,729)
Net deferred tax assets	$ 44,571	$ 27,388