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Net Loss Per Share - Anti-Dilutive Securities (Details) - $ / shares shares in Thousands | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share |  |
Anti-dilutive stock options not considered in computing diluted earnings per common share | 25,075 | 12,546
Unvested Stock |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share |  |
Anti-dilutive stock options not considered in computing diluted earnings per common share | 490 | 464
Shares excluded as performance conditions not yet satisfied | 10,800 | 26,400
Convertible Preferred Stock |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share |  |
Anti-dilutive stock options not considered in computing diluted earnings per common share | 11,127 |
Common Stock Warrants |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share |  |
Anti-dilutive stock options not considered in computing diluted earnings per common share | 1,376 |
IPO Warrants |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share |  |
Anti-dilutive stock options not considered in computing diluted earnings per common share | 12,082 | 12,082
Exercise price (per share) | $ 11.50 |
Redemption price (per share) | $ 0.01 |
Number of days of prior notice require to redeem | 30 days |
Sale price of stock (per share) | $ 17.50 |
Number of trading days considered for share price | 20 days |
Total number of trading days considered | 30 days |

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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