Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) - Assets Measured at Fair Value on a Recurring Basis [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	$ 5,022	$ 15,027
Liabilities measured at fair value	823	817
Available-for-sale securities/investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	2,007	9,719
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	5,022	15,027
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale securities/investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	2,007	9,719
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Liabilities measured at fair value	823	817
Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	3,015	5,308
Cash equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	3,015	5,308
Contingent consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Liabilities measured at fair value	823	817
Contingent consideration [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Liabilities measured at fair value	$ 823	$ 817