Nature of Operations and Summary of Significant Accounting Policies - Narrative (Details)	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2022 USD ($) institution	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) segment institution	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Feb. 05, 2021 USD ($)
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of financial services organizations, leading marketplace and financial technology brands (more than) | institution	7,800					7,800
Foreign currency translation adjustment		$ (13,595,000)	$ (1,862,000)	$ (3,129,000)	$ (16,724,000)	$ (27,559,000)	$ (455,000)	$ 3,635,000
Unbilled receivables	$ 1,900,000					1,900,000	0
Restructuring costs		$ 1,807,000			1,807,000	1,800,000	0	(114,000)
Other-than-temporary impairment charges recognized in earnings						0	0	0
Write-offs of allowance for doubtful accounts						0	100,000	200,000
Allowance for doubtful accounts receivable	900,000					900,000	400,000
Depreciation and amortization of property and equipment				555,000	$ 1,064,000	1,401,000	1,439,000	1,504,000
Repairs and maintenance expenses						100,000	100,000	100,000
Impairment or long-lived assets						0	0	0
Capitalized software development costs	0					0	0	0
Amortization expense for capitalized software development costs						0	0	0
Capitalized software development costs for internal use	800,000					800,000	800,000	300,000
Amortization expense for capitalized software development costs for internal use						$ 400,000	300,000	400,000
Number of operating segments | segment						1
Number of reporting units | segment						1
Goodwill impairment	0
Impairment to intangible assets						$ 0	0	0
Trading-day average stock price period						20 days
Advertising costs						$ 1,100,000	1,200,000	$ 1,600,000
Embedded conversion derivative	0					0	48,208,000
Convertible Debt | Convertible Senior Unsecured Notes Due 2026
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Interest rate on loan agreements									0.75%
Fair value of notes			28,500,000	28,500,000
Convertible Debt | Convertible Senior Unsecured Notes Due 2026 | Embedded conversion derivative
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Embedded conversion derivative	$ 0		$ 28,500,000	$ 28,500,000		$ 0	48,208,000		$ 33,200,000
Spanish Government Agencies | ICAR
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Interest rate on loan agreements	0.00%					0.00%
Total amounts outstanding under loan agreements	$ 1,300,000					$ 1,300,000	800,000
Spanish Government Agencies | ICAR | Other Current Liabilities
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Current amount outstanding under loan agreements	100,000					100,000	100,000
Spanish Government Agencies | ICAR | Other Noncurrent Liabilities
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Non-current amount outstanding under loan agreements	$ 1,200,000					$ 1,200,000	$ 700,000
Minimum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives						3 years
Minimum | Spanish Government Agencies | ICAR
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Repayment period of loan agreements						5 years
Maximum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives						7 years
Maximum | Spanish Government Agencies | ICAR
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Repayment period of loan agreements						12 years