NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - ADDITIONAL INFORMATION (Detail)	12 Months Ended
	Sep. 30, 2017 USD ($) patent segment institution	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Accounting Policies [Abstract]
Number of financial institutions signed agreements to deploy mobile deposit | institution	5,900
Number of top U.S. retail banks that deployed mobile deposit | institution	50
Number of patents granted | patent	35
Number of patent applications pending | patent	16
Currency translation adjustment	$ 208,000	$ (46,000)	$ 0
Number of operating segments | segment	1
Number of reporting units | segment	1
Impairment of goodwill and intangibles	$ 0
Other-than-temporary impairment charges recognized	0	0	0
Allowance for doubtful accounts	0	0	0
Allowance for doubtful accounts receivable	$ 31,000	35,000
Deferred software maintenance fees amortization period	1 year
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Depreciation	$ 322,000	790,000	433,000
Total repairs and maintenance expenses	200,000	200,000	100,000
Impairment charges	0	0	0
Software development costs capitalized	0	0
Amortization expense from capitalized software costs or purchased technology	0	0	0
Software development costs capitalized for internal use software	$ 0	0	0
Tax benefit is measured based on the largest benefit	Greater than 50%
Advertising costs	$ 300,000	200,000	$ 200,000
Accumulated other comprehensive loss	$ (147,000)	$ 42,000
Minimum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives	3 years
Maximum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives	5 years