Net Loss per Share - Summary of Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ 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 attributable to common stockholders - basic and diluted					$ (20,125)	$ (20,379)	$ (19,667)	$ (22,006)	$ (95,817)	$ (82,177)	$ (83,072)
Weighted-average shares used to compute basic and diluted net loss per share	34,609	29,574	29,489	29,422	29,379	29,354	29,293	27,810	30,784	28,964	18,922
Basic and diluted net loss per common share	$ (0.64)	$ (0.92)	$ (0.75)	$ (0.82)	$ (0.69)	$ (0.69)	$ (0.67)	$ (0.79)	$ (3.11)	$ (2.84)	$ (4.39)

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

No definition available.

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Period Type:	duration