Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, checkDeposits in Billions		3 Months Ended			9 Months Ended
	Oct. 01, 2019 USD ($)	Jun. 30, 2020 USD ($) institution checkDeposits patent $ / shares	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment patent institution checkDeposits $ / shares	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($) $ / shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of financial institutions signed agreements to deploy mobile deposit (more than) | institution		7,500			7,500
Number of check deposits processed (more than) | checkDeposits		4			4
Number of patents granted | patent		64			64
Number of pending patent applications | patent		19			19
Net gain (loss) resulting from foreign exchange translation		$ 1,135,000		$ 814,000	$ 1,324,000	$ (1,213,000)
Other than temporary impairments recognized on investments		0		0	0	0
Write-offs of allowance for doubtful accounts					100,000	100,000
Allowance for doubtful accounts receivable		200,000			200,000		$ 200,000
Capitalized software development costs		$ 0		$ 0	0	0
Amortization expense of capitalized software development costs					0	0
Capitalized software development costs for internal use					100,000	200,000
Amortization expense from capitalized software development costs for internal use					$ 300,000	300,000
Number of operating segments | segment					1
Number of reporting units | segment					1
Goodwill impairment			$ 0
Common stock, par value (in dollars per share) | $ / shares		$ 0.001			$ 0.001		$ 0.001
Impairment charges related to intangible assets					$ 0	$ 0
Trading-day average stock price period					20 days
Accumulated other comprehensive loss		$ 2,581,000			$ 2,581,000		$ 4,061,000
Operating lease liabilities	$ 8,200,000	7,325,000			7,325,000
Operating ROU assets	$ 6,800,000	$ 5,683,000			$ 5,683,000
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member					us-gaap:AccountingStandardsUpdate201409Member
ICAR | Spanish Government Agencies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest rate on loan agreement		0.00%			0.00%
Amount outstanding under loan agreement		$ 700,000			$ 700,000		600,000
ICAR | Spanish Government Agencies | Other current liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amount outstanding under loan agreement		100,000			100,000		200,000
ICAR | Spanish Government Agencies | Other non-current liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amount outstanding under loan agreement		$ 600,000			$ 600,000		$ 400,000
Minimum | ICAR | Spanish Government Agencies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Term of loan agreement					5 years
Maximum | ICAR | Spanish Government Agencies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Term of loan agreement					12 years