Nature of Operations and Summary of Significant Accounting Policies - Cumulative Effect of Adoption of ASC 606 on Consolidated Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Oct. 01, 2018
Assets
Accounts receivable, net	$ 14,938				$ 16,821								$ 14,938	$ 16,821
Contract assets	2,350												2,350			$ 169
Deferred income taxes, net	16,596				15,356								16,596	15,356		15,089
Other non-current assets	2,347				2,147								2,347	2,147		2,654
Liabilities
Deferred revenue, current portion	5,612				4,792								5,612	4,792		4,281
Deferred revenue, non-current portion	736				485								736	485		485
Equity [Abstract]
Accumulated deficit	(20,806)				(21,002)								(20,806)	(21,002)		$ (20,082)
Revenue
Revenue	25,018	$ 21,906	$ 19,983	$ 17,683	21,037	$ 16,109	$ 14,277	$ 12,136	$ 12,904	$ 11,798	$ 11,419	$ 9,269	84,590	63,559	$ 45,390
Operating expenses
Selling and marketing													27,405	21,700	14,484
Software and hardware
Revenue
Revenue													46,845	40,698	29,647
Service and other
Revenue
Revenue													37,745	22,861	$ 15,743
Adjustments Due to the Adoption of ASC 606 | ASC 606
Assets
Accounts receivable, net	414												414
Contract assets	(2,350)				169								(2,350)	169
Deferred income taxes, net	822				(267)								822	(267)
Other non-current assets	(596)				507								(596)	507
Liabilities
Deferred revenue, current portion	1,124				(511)								1,124	(511)
Deferred revenue, non-current portion	0				0								0	0
Equity [Abstract]
Accumulated deficit	(2,834)				920								(2,834)	920
Revenue
Revenue													(2,454)
Operating expenses
Selling and marketing													15
Adjustments Due to the Adoption of ASC 606 | ASC 606 | Software and hardware
Revenue
Revenue													(2,454)
Adjustments Due to the Adoption of ASC 606 | ASC 606 | Service and other
Revenue
Revenue													0
Balances without adoption of ASC 606
Assets
Accounts receivable, net	15,352												15,352
Contract assets	0				0								0	0
Deferred income taxes, net	17,418				15,356								17,418	15,356
Other non-current assets	1,751				2,147								1,751	2,147
Liabilities
Deferred revenue, current portion	6,736				4,792								6,736	4,792
Deferred revenue, non-current portion	736				485								736	485
Equity [Abstract]
Accumulated deficit	$ (23,640)				$ (21,002)								(23,640)	$ (21,002)
Revenue
Revenue													82,136
Operating expenses
Selling and marketing													27,420
Balances without adoption of ASC 606 | Software and hardware
Revenue
Revenue													44,391
Balances without adoption of ASC 606 | Service and other
Revenue
Revenue													$ 37,745