Revenue Recognition - Summary of Revenues Classified by Major Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Total net revenues	$ 77,459	$ 72,484
United States
Revenues:
Total net revenues	35,041	38,064
Other Americas
Revenues:
Total net revenues	8	354
Germany
Revenues:
Total net revenues	20,217	13,716
Other Europe, Middle East and Africa
Revenues:
Total net revenues	4,597	4,784
Japan
Revenues:
Total net revenues	11,411	9,753
Other Asia-Pacific
Revenues:
Total net revenues	$ 6,185	$ 5,813