Revenue - Impact of Adoption on Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss)	$ (1,788)	$ 320
Capitalized commissions	70	0
Prepaid expenses and other current assets and other long-term assets	24	106
Accounts payable and accrued liabilities	(750)	(202)
Other long-term liabilities	(22)	(69)
Unearned revenue	(1,183)	(1,273)
Net cash used in operating activities	248	$ 231
Amounts without ASC 606 impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss)	(1,592)
Capitalized commissions	0
Unearned revenue	(1,309)
Net cash used in operating activities	248
Accounting Standards Update 2014-09 | ASC 606 adoption impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss)	196
Capitalized commissions	(70)
Unearned revenue	(126)
Net cash used in operating activities	$ 0