Revenue Recognition - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2019	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Cost of revenue reognized from deferred contract cost	$ 0	$ 8,000
Deferred Revenue
Disaggregation Of Revenue [Line Items]
Deferred contract liabilities	100,000	100,000	$ 200,000
Prepaid Expenses and Other Current Assets
Disaggregation Of Revenue [Line Items]
Deferred contract costs	$ 35,000	$ 35,000	$ 27,000