Summary of Significant Accounting Policies and Select Balance Sheet Information - Additional Information (Detail 1)	12 Months Ended
	Sep. 30, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Summary Of Significant Accounting Policies [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	five years
Remaining performance obligation, expected timing of satisfaction, percentage	76.00%
Revenue remaining performance obligation expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-10-01
Summary Of Significant Accounting Policies [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	four years
Remaining performance obligation, expected timing of satisfaction, percentage	24.00%