Net Loss per Share - Reconciliation of the Numerator and Denominator used in Computing Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net loss	$ (7,732)	$ (977)	$ (22,174)	$ (3,137)
Denominator:
Weighted-average shares outstanding	21,359	20,728	21,262	20,591
Weighted-average unvested shares subject to repurchase	(26)	(92)	(33)	(100)
Weighted-average shares outstanding — basic and diluted	21,333	20,636	21,229	20,491
Net loss per share — basic and diluted	$ (0.36)	$ (0.05)	$ (1.04)	$ (0.15)

Weighted average number basic shares outstanding adjustment.

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- Definition

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.

+ References

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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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- Definition

Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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- Definition

Number of shares of common stock subject to repurchase or cancellation determined by relating the portion of time within a reporting period that these shares have been outstanding to the total time in that period. Common stock subject to repurchase are outstanding common shares that are contingently returnable (that is, subject to recall).

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