Revenue - Impact of Adoption on Statement of Cash Flows (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, 2019	Sep. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss	$ (179)	$ (159)	$ (1,486)	$ (1,788)	$ (10,017)	$ (1,020)	$ (1,449)	$ 320	$ (3,612)	$ (12,166)
Capitalized commissions									123
Prepaid expenses and other current assets									15	132
Accounts payable and accrued liabilities									(204)	268
Other long-term liabilities									(68)	(169)
Unearned revenue									(900)	(920)
Net cash used in operating activities									(736)	$ (638)
Amounts without ASC 606 impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss									(3,344)
Capitalized commissions									0
Unearned revenue									(1,045)
Net cash used in operating activities									(736)
Accounting Standards Update 2014-09 | ASC 606 adoption impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net loss									268
Capitalized commissions									(123)
Unearned revenue									(145)
Net cash used in operating activities									$ 0