Investments - Summary of Fair Values of Investments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	$ 16,502	$ 8,448
Total assets at fair value	18,054	8,448
Acquisition-related contingent consideration	1,601	3,051
Total liabilities at fair value	1,601	3,051
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	4,242	3,683
Long-term investments at fair value	1,101
Corporate debt securities | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	2,503	2,847
Long-term investments at fair value	451	0
Corporate debt securities | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	1,371	1,918
Long-term investments at fair value		0
Commercial paper | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	5,560	0
Commercial paper | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	2,826	0
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	4,242	3,683
Total assets at fair value	5,343	3,683
Acquisition-related contingent consideration	0	0
Total liabilities at fair value	0	0
Quoted Prices in Active Markets (Level 1) | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	4,242	3,683
Long-term investments at fair value	1,101
Quoted Prices in Active Markets (Level 1) | Corporate debt securities | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value	0	0
Quoted Prices in Active Markets (Level 1) | Corporate debt securities | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value		0
Quoted Prices in Active Markets (Level 1) | Commercial paper | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Quoted Prices in Active Markets (Level 1) | Commercial paper | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	12,260	4,765
Total assets at fair value	12,711	4,765
Acquisition-related contingent consideration	0	0
Total liabilities at fair value	0	0
Significant Other Observable Inputs (Level 2) | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value	0
Significant Other Observable Inputs (Level 2) | Corporate debt securities | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	2,503	2,847
Long-term investments at fair value	451	0
Significant Other Observable Inputs (Level 2) | Corporate debt securities | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	1,371	1,918
Long-term investments at fair value		0
Significant Other Observable Inputs (Level 2) | Commercial paper | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	5,560	0
Significant Other Observable Inputs (Level 2) | Commercial paper | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	2,826	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Total assets at fair value	0	0
Acquisition-related contingent consideration	1,601	3,051
Total liabilities at fair value	1,601	3,051
Significant Unobservable Inputs (Level 3) | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Long-term investments at fair value		0
Significant Unobservable Inputs (Level 3) | Commercial paper | Financial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	0	0
Significant Unobservable Inputs (Level 3) | Commercial paper | Industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments at fair value	$ 0	$ 0