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Stockholders' Equity - Pre-Funded Series D Warrant Exercises - Additional Information (Details) - USD ($) $ in Millions | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 21, 2018
Stockholders Equity Note [Line Items] |  |  |  |
Warrants exercised | 11,285 | 6,536 | 1 |
Pre-Funded Series D Warrants [Member] |  |  |  |
Stockholders Equity Note [Line Items] |  |  |  |
Warrants exercised |  | 5,379 |  |
Pre-Funded Series D Warrants [Member] | Maximum [Member] |  |  |  |
Stockholders Equity Note [Line Items] |  |  |  |
Maximum offering and selling of stock and securities that entity make to raise capital |  |  |  | $ 100.0

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- Definition The number of each class of warrants or rights exercised during the period. + References No definition available. + Details
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- Definition Securities issuable to raise capital authorized amount. + References No definition available. + Details
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- Details
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- Details
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