Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, institution in Thousands, deposit in Billions	3 Months Ended			6 Months Ended
	Mar. 31, 2020 USD ($) patent deposit institution $ / shares	Sep. 30, 2019 USD ($) $ / shares	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) patent institution segment deposit $ / shares	Mar. 31, 2019 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	7			7
Number of check deposits processed (more than) | deposit	3			3
Number of patents granted | patent	63			63
Number of pending patent applications | patent	19			19
Net (loss) gain resulting from foreign exchange translation	$ (1,064,000)		$ (1,203,000)	$ 189,000	$ (2,027,000)
Other-than-temporary impairments recognized on investments	0		0	0	0
Write-offs of allowance for doubtful accounts				0	100,000
Allowance for doubtful accounts receivable	400,000	$ 200,000		400,000
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	100,000
Amortization expense from capitalized software development costs for internal use			$ 200,000	$ 200,000
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	$ 3,814,000	$ 4,061,000		$ 3,814,000
Operating lease liabilities	7,512,000			7,512,000
Operating ROU assets	$ 5,999,000			$ 5,999,000
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%			0.00%
Amount outstanding under loan agreement	$ 500,000	600,000		$ 500,000
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		100,000
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		$ 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