Fair Value Measurements - Summary of Financial Assets that are Measured at Fair Value and Indicates the Fair Value Hierarchy of the Valuation Inputs (Details) - USD ($)	Sep. 30, 2020	Sep. 30, 2019
Assets:
Cash and cash equivalents		$ 0
Marketable securities		$ 0
Total assets	$ 113,099,000
Money Market Funds
Assets:
Cash and cash equivalents	101,437,000
Commercial Paper
Assets:
Marketable securities	9,883,000
Corporate Bonds
Assets:
Marketable securities	1,779,000
Level 1
Assets:
Total assets	101,437,000
Level 1 | Money Market Funds
Assets:
Cash and cash equivalents	101,437,000
Level 2
Assets:
Total assets	11,662,000
Level 2 | Commercial Paper
Assets:
Marketable securities	9,883,000
Level 2 | Corporate Bonds
Assets:
Marketable securities	$ 1,779,000