Net Loss per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net loss	$ (7,495)	$ (5,260)	$ (4,131)	$ (3,581)	$ (4,838)	$ (3,562)	$ (5,024)	$ (2,133)	$ (20,467)	$ (15,557)	$ (9,890)
Weighted-average common shares outstanding, basic and diluted (in shares)									4,221,893	573,181	531,430
Net loss per share, basic and diluted (in dollars per share)	$ (0.51)	$ (5.46)	$ (7.15)	$ (6.22)	$ (8.42)	$ (6.21)	$ (8.75)	$ (3.74)	$ (4.85)	$ (27.14)	$ (18.61)