Redeemable Convertible Preferred Stock - Additional Information (Details) $ / shares in Units, $ in Thousands |
1 Months Ended | 3 Months Ended | 9 Months Ended | |||||
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Oct. 01, 2018 |
Aug. 31, 2017
$ / shares
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Jul. 31, 2018
USD ($)
$ / shares
shares
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Sep. 30, 2018
USD ($)
Director
$ / shares
shares
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Sep. 30, 2017
USD ($)
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Dec. 31, 2017
$ / shares
shares
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Temporary Equity [Line Items] | ||||||||
Funding through sale of stock | $ | $ 84,739 | $ 0 | ||||||
Temporary equity, description | At the election of the holders of a majority of the then-outstanding shares of preferred stock, voting together as a single class on an as-converted to common stock basis, the Company will redeem all outstanding shares of preferred stock in three equal annual installments commencing May 24, 2023, by paying in cash an amount per share equal to the original issuance prices of $0.59 per share of Series A redeemable convertible preferred stock, $0.8822 per share of Series B redeemable convertible preferred stock, $0.4797 per share of Series C redeemable convertible preferred stock, $0.5996 per share of Series C-2 redeemable convertible preferred stock, $0.5996 per share of Series D redeemable convertible preferred stock, $0.6596 per share of Series D-2 redeemable convertible preferred stock, and $0.2674 per share of Series E redeemable convertible preferred stock, plus 8% of the applicable original issuance prices per annum calculated from the original issuance date of each share of preferred stock. | |||||||
Preferred stock redemption commencing period | May 24, 2023 | |||||||
Percentage of issuance price calculated per annum added to original issuance price to determine redemption price | 8.00% | |||||||
Number of directors common shareholders are entitled to elect | Director | 1 | |||||||
Voting rights per share | one vote per share | |||||||
Series E Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Funding through sale of stock | $ | $ 85,400 | |||||||
Sale and issuance of shares | shares | 319,305,718 | |||||||
Redeemable convertible preferred stock, par value | $ 0.2674 | |||||||
Original issuance price, per share | $ 0.2674 | |||||||
Dividends declared per share rate | $ 0.0214 | |||||||
Number of directors preferred shareholders are entitled to elect | Director | 1 | |||||||
Redeemable conversion price per share | $ 0.2674 | |||||||
Preferred stock, conversion basis | 1-for-0.0275 | |||||||
Exercise price per share | $ 0.2674 | $ 0.2674 | ||||||
Series E Redeemable Convertible Preferred Stock | Oxford Finance LLC and Silicon Valley Bank | Loan and Security Agreement | ||||||||
Temporary Equity [Line Items] | ||||||||
Issuance of warrants to purchase shares | shares | 1,682,871 | |||||||
Exercise price per share | $ 0.2674 | |||||||
Term of warrant exercisable | 10 years | |||||||
Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Sale and issuance of shares | shares | 493,615,703 | 173,750,421 | ||||||
Redeemable convertible preferred stock, par value | $ 0.001 | $ 0.001 | ||||||
Temporary Equity liquidation percentage of voting power | Unless the holders of a majority of the then-outstanding shares of preferred stock, voting together as a single class on an as-converted to common stock basis, elect otherwise, any of the following events shall be treated as a liquidation: (i) any consolidation, merger, acquisition, or any other corporate reorganization in which the stockholders of the Company immediately prior to such event own less than 50% of the voting power of the surviving or successor entity or its parent immediately after such event; (ii) any transaction or series of related transactions in which in excess of 50% of the Company’s voting power is transferred; or (iii) any sale, lease, transfer, exclusive license, or other disposition of all or substantially all of the assets of the Company. | |||||||
Series A Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | $ 0.5900 | 0.5900 | ||||||
Dividends declared per share rate | $ 0.0472 | |||||||
Number of directors preferred shareholders are entitled to elect | Director | 1 | |||||||
Redeemable conversion price per share | $ 0.3756 | |||||||
Preferred stock, conversion basis | 1-for-0.0433 | |||||||
Series B Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | 0.8822 | 0.8822 | ||||||
Dividends declared per share rate | $ 0.07056 | |||||||
Number of directors preferred shareholders are entitled to elect | Director | 1 | |||||||
Redeemable conversion price per share | $ 0.4203 | |||||||
Preferred stock, conversion basis | 1-for-0.0578 | |||||||
Exercise price per share | 0.8822 | 0.8822 | ||||||
Series C Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | 0.4797 | 0.4797 | ||||||
Dividends declared per share rate | $ 0.03838 | |||||||
Number of directors preferred shareholders are entitled to elect | Director | 2 | |||||||
Redeemable conversion price per share | $ 0.3573 | |||||||
Preferred stock, conversion basis | 1-for-0.0370 | |||||||
Exercise price per share | [1] | 0.4797 | 0.4797 | |||||
Series C-2 Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | 0.5996 | 0.5996 | ||||||
Dividends declared per share rate | 0.048 | |||||||
Redeemable conversion price per share | 0.4081 | |||||||
Preferred stock, conversion basis | 1-for-0.0405 | |||||||
Series D Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | 0.5996 | 0.5996 | ||||||
Dividends declared per share rate | 0.048 | |||||||
Redeemable conversion price per share | 0.4081 | |||||||
Preferred stock, conversion basis | 1-for-0.0405 | |||||||
Series D-2 Redeemable Convertible Preferred Stock | ||||||||
Temporary Equity [Line Items] | ||||||||
Original issuance price, per share | 0.6596 | 0.6596 | ||||||
Dividends declared per share rate | 0.0528 | |||||||
Redeemable conversion price per share | 0.4336 | |||||||
Preferred stock, conversion basis | 1-for-0.0419 | |||||||
Exercise price per share | $ 0.6596 | $ 0.6596 | ||||||
Series D-2 Redeemable Convertible Preferred Stock | Oxford Finance LLC and Silicon Valley Bank | Loan and Security Agreement | ||||||||
Temporary Equity [Line Items] | ||||||||
Issuance of warrants to purchase shares | shares | 682,230 | |||||||
Exercise price per share | $ 0.6596 | |||||||
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