Revenue Recognition (Tables)

12 Months Ended

Sep. 30, 2020

Revenue From Contract With Customer [Abstract]

Summary of Revenues Classified by Major Geographic Region

Revenues, classified by the major geographic region in which our customers are located, for the fiscal years ended September 30, 2020, 2019 and 2018 (dollars in thousands):

	September 30,
	2020		2019		2018
	(ASC 606)		(ASC 606)		(ASC 605)
Revenues:
United States	$	128,381	$	131,877	$	109,564
Other Americas		16		1,044		1,492
Germany		100,674		78,258		64,417
Other Europe, Middle East and Africa		25,394		20,478		16,755
Japan		50,936		44,472		57,303
Other Asia-Pacific		24,245		27,186		27,453
Total net revenues (1)	$	329,646	$	303,315	$	276,984

(1) As a result of our adoption of ASC 606 effective October 1, 2018 using the modified retrospective method, prior period amounts have not been adjusted to conform with ASC 606 and therefore may not be comparable.

Summary of Significant Changes in Contract Assets and Deferred Revenue

The table below shows significant changes in contract assets (dollars in thousands):

	Contract assets
Balance as of October 1, 2018	$	6,470
Revenues recognized but not billed		42,661
Amounts reclassified to accounts receivable, net		(39,912	)
Balance as of September 30, 2019	$	9,219
Revenues recognized but not billed		52,682
Amounts reclassified to accounts receivable, net		(31,624	)
Balance as of September 30, 2020	$	30,277

The table below shows significant changes in deferred revenue (dollars in thousands):

	Deferred revenue
Balance as of October 1, 2018	$	335,252
Amounts billed but not recognized		117,201
Revenue recognized		(99,169	)
Balance as of September 30, 2019	$	353,284
Amounts billed but not recognized		96,126
Revenue recognized		(124,317	)
Balance as of September 30, 2020	$	325,093

Deferred revenue consisted of the following (dollars in thousands):

	September 30,
	2020		2019
Current Liabilities:
Unearned revenue	$	112,520	$	88,233
Total	$	112,520	$	88,233
Non-current Liabilities:
Unearned revenue		212,573		265,051
Total	$	212,573	$	265,051

Summary of Estimated Revenue Expected to be Recognized in Future Related to Performance Obligations Unsatisfied or Partially Unsatisfied

The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied at September 30, 2020 (dollars in thousands):

	Within One Year		Two to Five Years		Greater than Five Years		Total
Total revenue	$	148,936	$	189,538	$	49,010	$	387,484