Revenue from Contract with Customer - Additional Information (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue recognized included in contract liability balance at the beginning of the period	$ 3,900,000	$ 4,400,000
Impairment losses recognized in capitalized contract costs	0	0
Selling and marketing
Disaggregation of Revenue [Line Items]
Amortization of capitalized contract costs	800,000	600,000
Other current and non-current assets
Disaggregation of Revenue [Line Items]
Capitalized contract costs	$ 1,500,000	$ 1,500,000