Redeemable Convertible Preferred Stock - Narrative (Details) - USD ($) |
4 Months Ended | 9 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|
Sep. 22, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2017 |
Jun. 30, 2017 |
Jun. 09, 2017 |
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| Temporary Equity [Line Items] | ||||||
| Payments of issuance costs | $ (29,284,000) | |||||
| Series A convertible preferred stock | ||||||
| Temporary Equity [Line Items] | ||||||
| Agreement to sell shares (in shares) | 480,000 | |||||
| Share price (in dollars per share) | $ 1,000 | |||||
| Agreement to sell shares | $ 480,000,000.0 | |||||
| Payments of issuance costs | $ (29,300,000) | $ (29,318,000) | $ (29,318,000) | |||
| Proceeds from issuance of redeemable convertible preferred stock | $ 450,700,000 | |||||
| Series A convertible preferred stock | Initial closing | ||||||
| Temporary Equity [Line Items] | ||||||
| Agreement to sell shares (in shares) | 172,500 | |||||
| Agreement to sell shares | $ 172,500,000 | |||||
| Series A convertible preferred stock | Second closing | ||||||
| Temporary Equity [Line Items] | ||||||
| Agreement to sell shares (in shares) | 307,500 | |||||
| Agreement to sell shares | $ 307,500,000 | |||||
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- Definition The cash outflow for cost incurred directly with the issuance of an equity security. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The cash inflow from issuance of preferred stocks identified as being convertible into another form of financial instrument, typically the entity's common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Per share or per unit amount of equity securities issued. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The number of securities classified as temporary equity that have been allocated to investors to buy. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Aggregate monetary value of a new issue of securities which have been allocated to investors to buy. When security is sold on a subscription basis, the issuer does not initially receive the total proceeds. In general, the issuer does not issue the security to the investor until it receives the entire proceeds. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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