Geographic, Product and Industry Information - Summary of Revenue by Geographic Region (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenue	$ 90,100	$ 54,385	$ 25,427
United States [Member]
Segment Reporting Information [Line Items]
Revenue	58,080	35,936	17,662
EMEA [Member]
Segment Reporting Information [Line Items]
Revenue	25,821	14,692	6,557
APAC [Member]
Segment Reporting Information [Line Items]
Revenue	5,115	2,761	1,001
Americas [Member]
Segment Reporting Information [Line Items]
Revenue	$ 1,084	$ 996	$ 207