Revenue Recognition - Summary of Revenues Classified by Major Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended					6 Months Ended		12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Revenues:
Total net revenues	$ 98,662	$ 93,643	$ 75,197	$ 86,823	$ 77,705	$ 192,305	$ 164,528	$ 330,967
United States
Revenues:
Total net revenues	36,781			36,742		68,875	71,938
Other Americas
Revenues:
Total net revenues	25					68	8
Germany
Revenues:
Total net revenues	24,667			20,102		56,711	40,319
Other Europe, Middle East and Africa
Revenues:
Total net revenues	13,196			8,628		16,665	13,225
Japan
Revenues:
Total net revenues	13,779			15,518		26,452	26,929
Other Asia-Pacific
Revenues:
Total net revenues	$ 10,214			$ 5,833		$ 23,534	$ 12,109