Revenue - Impact of Adoption on Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	$ (1,486)	$ (1,449)	$ (3,274)	$ (1,129)
Capitalized commissions			105	0
Prepaid expenses and other current assets			(25)	381
Accounts payable and accrued liabilities			89	700
Other long-term liabilities			(33)	(101)
Unearned revenue			(1,704)	(2,789)
Net cash used in operating activities			(3,251)	$ (548)
Amounts without ASC 606 impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	(1,431)		(3,023)
Capitalized commissions			0
Prepaid expenses and other current assets			(25)
Unearned revenue			(1,850)
Net cash used in operating activities			(3,251)
Accounting Standards Update 2014-09 | ASC 606 adoption impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	$ 55		251
Capitalized commissions			(105)
Prepaid expenses and other current assets			0
Unearned revenue			(146)
Net cash used in operating activities			$ 0