Segment Information - Revenue from External Customers Attributed to Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 315,349	$ 220,350	$ 851,439	$ 651,077
Asia/Pacific/Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	151,086	99,415	395,138	307,969
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	55,062	30,228	137,945	76,435
TAIWAN, PROVINCE OF CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	29,844	15,266	73,350	91,993
KOREA, REPUBLIC OF
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	28,994	22,369	77,982	46,296
Asia Pacific, Other than China, Taiwan, and Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	37,186	31,552	105,861	93,245
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	110,454	79,882	313,830	246,000
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	108,344	79,032	290,883	243,883
North America, Other than United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	2,110	850	22,947	2,117
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 53,809	$ 41,053	$ 142,471	$ 97,108