Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($) Patents Institution	Sep. 30, 2016 USD ($) Patents Institution Reporting Segment	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of patents granted | Patents	27	27
Number of patent applications pending | Patents	16	16
Number of financial institutions signed agreements to deploy mobile deposit | Institution	5,400	5,400
Number of top U.S. retail banks that deployed mobile deposit | Institution	50	50
Foreign currency translation adjustment		$ 46,000	$ 0	$ 0
Impairment of goodwill and intangibles	$ 0
Number of reporting unit | Reporting		1
Other-than-temporary impairment charges recognized		$ 0	0	0
Allowance for doubtful accounts		0	0
Allowance for doubtful accounts receivable	35,000	$ 35,000	13,000
Deferred software maintenance fees amortization period		1 year
Depreciation and amortization of property and equipment total		$ 800,000	400,000	500,000
Fixed assets acquired under capital leases	2,743,000	2,743,000	2,505,000
Total repairs and maintenance expenses		200,000	100,000	100,000
Impairment charges		0	0	0
Software development costs capitalized	0	$ 0	0
Tax benefit is measured based on the largest benefit		Greater than 50%
Advertising costs		$ 200,000	200,000	100,000
Number of operating segment | Segment		1
Accumulated other comprehensive loss	42,000	$ 42,000	3,000
ASU No 2015-17 [Member] | Early adoption [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
New accounting guidance, no adjustment made to prior periods		true
Minimum [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives		3 years
Maximum [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives		5 years
Assets acquired under capital leases [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Fixed assets acquired under capital leases	100,000	$ 100,000	100,000
Equipment [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Fixed assets acquired under capital leases	1,476,000	1,476,000	1,281,000
Depreciation expense under capital lease		19,000	19,000	$ 19,000
Accumulated depreciation	$ 100,000	$ 100,000	$ 100,000