Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								8 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, 2014	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net loss	$ (10,563)	$ (7,482)	$ (6,900)	$ (6,689)	$ (5,245)	$ (3,019)	$ (3,040)	$ (1,093)	$ (9,539)	$ (31,634)	$ (12,397)
Weighted average common units outstanding, basic and diluted									826
Weighted average shares outstanding, basic and diluted	34,507	34,316	19,121	676	548	294	1,284	1,284	826	22,222	243
Net loss per common unit, basic and diluted									$ (11.55)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.31)	$ (0.22)	$ (0.36)	$ (9.89)	$ (9.57)	$ (10.27)	$ (2.37)	$ (0.85)	$ (11.55)	$ (1.42)	$ (51.02)