Quarterly Financial Data (unaudited) - Quarterly Financial Data Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenue	$ 9,455	$ 9,817	$ 9,612	$ 9,091	$ 9,056	$ 10,556	$ 8,106	$ 8,741	$ 37,975	$ 36,459
Gross margin	7,102	7,235	7,273	6,380	6,450	7,088	6,216	6,070	27,990	25,824
Income (loss) from operations	(493)	(452)	(214)	(1,117)	(908)	(885)	(1,072)	(1,227)	(2,276)	(4,092)
Net income (loss)	$ (847)	$ (552)	$ (711)	$ (1,207)	$ (1,222)	$ (921)	$ (1,350)	$ (1,032)	$ (3,317)	$ (4,525)
Basic and diluted net income (loss) per share	$ (0.19)	$ (0.13)	$ (0.16)	$ (0.28)	$ (0.28)	$ (0.21)	$ (0.31)	$ (0.24)