Shareholders' Equity - Reconciliation of Beginning and Ending Balances in Shareholders' Equity (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Dec. 31, 2018 |
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| Class Of Stock [Line Items] | |||||
| Shareholders' equity, Beginning Balance | $ 71,622 | $ 39,494 | $ 39,494 | ||
| Exercise of share options | 59 | ||||
| Conversion of preferred shares to ordinary shares | 74 | ||||
| Share-based compensation expense | 1,113 | 404 | |||
| Issuance of warrants | 139 | ||||
| Net loss | $ (27,638) | $ (15,747) | (48,218) | (27,893) | (77,056) |
| Shareholders' equity, Ending Balance | $ 24,576 | $ 118,530 | $ 24,576 | 118,530 | $ 71,622 |
| Series B Convertible Preferred Shares | |||||
| Class Of Stock [Line Items] | |||||
| Issuance of shares | 32,159 | ||||
| Common Stock | |||||
| Class Of Stock [Line Items] | |||||
| Issuance of shares | $ 74,153 | ||||
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- Definition Class of warrant or right number of securities called by warrants or rights amount. 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 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/disclosureRef
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- Definition The gross value of stock issued during the period upon the conversion of convertible securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Value of stock (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of stock value of such awards forfeited. Stock issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Value of stock issued as a result of the exercise of stock options. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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