Revenue - Impact of Adoption on Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 7,502	$ 8,895
Cost of revenues	1,842	2,425
Gross margin	5,660	6,470
Selling and marketing (operating expenses)	3,943	4,110
Loss from operations	(1,654)	(966)
Loss before income taxes	(1,800)	(1,067)
Net income (loss)	(1,788)	320
Net loss attributable to common stockholders	$ (1,841)	$ 248
Loss per common share - basic (in usd per share)	$ (0.36)	$ 0.06
Loss per common share – diluted (in usd per share)	$ (0.36)	$ 0.06
Amounts without ASC 606 impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 7,628
Cost of revenues	1,842
Gross margin	5,786
Selling and marketing (operating expenses)	3,873
Loss from operations	(1,458)
Loss before income taxes	(1,604)
Net income (loss)	(1,592)
Net loss attributable to common stockholders	$ (1,645)
Loss per common share - basic (in usd per share)	$ (0.32)
Loss per common share – diluted (in usd per share)	$ (0.32)
Accounting Standards Update 2014-09 | ASC 606 adoption impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 126
Cost of revenues	0
Gross margin	126
Selling and marketing (operating expenses)	(70)
Loss from operations	196
Loss before income taxes	196
Net income (loss)	196
Net loss attributable to common stockholders	$ 196
Loss per common share - basic (in usd per share)	$ 0.04
Loss per common share – diluted (in usd per share)	$ 0.04
Product and other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 1,751	$ 3,080
Cost of revenues	651	$ 1,280
Product and other | Amounts without ASC 606 impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	1,877
Cost of revenues	651
Product and other | Accounting Standards Update 2014-09 | ASC 606 adoption impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	126
Cost of revenues	$ 0