Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, deposit in Billions	3 Months Ended
	Dec. 31, 2019 USD ($) segment patent deposit institution $ / shares	Sep. 30, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Oct. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of financial institutions signed agreements to deploy mobile deposit (more than) | institution	6,500
Number of check deposits processed (more than) | deposit	3
Number of patents granted | patent	58
Number of pending patent applications | patent	24
Net gain (loss) resulting from foreign exchange translation	$ 1,253,000		$ (824,000)
Other-than-temporary impairments recognized on investments	0		0
Write-offs of allowance for doubtful accounts	0		0
Allowance for doubtful accounts receivable	300,000	$ 200,000
Capitalized software development costs	0		0
Amortization expense of capitalized software development costs	0		0
Capitalized software development costs for internal use	23,000		49,000
Amortization expense from capitalized software development costs for internal use	$ 100,000		100,000
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
Impairment charges related to intangible assets	$ 0		$ 0
Trading-day average stock price period	20 days
Accumulated other comprehensive loss	$ 2,806,000	$ 4,061,000
Operating lease liabilities	8,004,000
Operating ROU assets	$ 6,535,000
ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities				$ 8,200,000
Operating ROU assets				$ 6,800,000
ICAR | Spanish Government Agencies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest rate on loan agreement	0.00%
Amount outstanding under loan agreement	$ 500,000	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	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	$ 400,000	$ 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