Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands |
9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Numerator | ||||
| Net loss | $ (46,811) | $ (17,915) | $ (26,979) | $ (6,210) |
| Accretion of redeemable convertible preferred stock | (4,470) | (2,383) | (3,204) | (3,330) |
| Net loss attributable to common stockholders | $ (51,281) | $ (20,298) | $ (30,183) | $ (9,540) |
| Denominator | ||||
| Weighted-average common shares outstanding | 8,820,609 | 2,068,164 | 2,205,577 | 1,631,660 |
| Less: Weighted-average shares subject to repurchase | (180,431) | (110,568) | (137,243) | (214,928) |
| Denominator for basic and diluted net loss per share attributable to common stockholders | 8,640,178 | 1,957,596 | 2,068,334 | 1,416,732 |
| Basic and diluted net loss per share attributable to common stockholders | $ (5.94) | $ (10.37) | $ (14.59) | $ (6.73) |
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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. No definition available.
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- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of accelerated share repurchase agreements. An accelerated share repurchase program is a combination of transactions that permits an entity to purchase a targeted number of shares immediately with the final purchase price of those shares determined by an average market price over a fixed period of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of decrease to net income for accretion of temporary equity to its redemption value to derive net income apportioned to common stockholders. No definition available.
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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). No definition available.
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- References No definition available.
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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