Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 30,390	$ 29,256	$ 29,905	$ 26,111	$ 27,120	$ 24,989	$ 16,934	$ 16,559	$ 115,662	$ 85,602
Gross margin	7,253	6,385	6,401	5,811	6,229	5,456	3,224	2,917	25,850	17,826
Income from operations	2,149	1,753	1,839	889	1,325	1,668	689	382	6,630	4,064
Other income (expense), net	(340)	(269)	(255)	(364)	(542)	(374)	(127)	(575)	(1,228)	(823)
Income before income taxes	1,809	1,484	1,584	525	783	1,294	562	(193)	5,402	2,446
Income tax expense (benefit), net	769	539	605	201	(1,604)	518	225	(77)	2,114	(938)
Net income	$ 1,040	$ 945	$ 979	$ 324	$ 2,387	$ 776	$ 337	$ (116)	$ 3,288	$ 3,384
Net income (loss) per share - basic (in dollars per share)	$ 0.09	$ 0.08	$ 0.09	$ 0.03	$ 0.23	$ 0.08	$ 0.03	$ (0.01)	$ 0.29	$ 0.34
Net income (loss) per share - diluted (in dollars per share)	$ 0.08	$ 0.08	$ 0.08	$ 0.03	$ 0.20	$ 0.07	$ 0.03	$ (0.01)	$ 0.27	$ 0.30