Net Loss Per Share Available to Common Stockholders - Calculation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net loss available to common stockholders		$ (7,549)	$ (3,053)	$ (24,220)	$ (11,884)
Denominator:
Weighted average number of shares, basic and diluted	[1]	5,651	5,503	5,625	5,456
Net loss per share available to common stockholders
Basic and diluted net loss per common share available to common stockholders	[1]	$ (1.34)	$ (0.55)	$ (4.31)	$ (2.18)

[1] All share and per share amounts of our common stock for all periods presented have been retroactively adjusted to reflect the one-for-seven reverse stock split of the Company’s issued and outstanding common stock, which took effect on October 5, 2017 (Note 1).