Stock-based Compensation - RSU Activity (Details) - RSU shares in Thousands  | 
9 Months Ended | 
|---|---|
| 
 Sep. 30, 2019  
$ / shares  
shares 
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| Number of Shares | |
| Beginning Balance (in shares) | shares | 278 | 
| Granted (in shares) | shares | 560 | 
| Vested (in shares) | shares | (622) | 
| Forfeited (in shares) | shares | (79) | 
| Ending Balance (in shares) | shares | 137 | 
| Weighted- Average Grant Date Fair Value | |
| Beginning Balance (in dollars per share) | $ / shares | $ 1.83 | 
| Granted (in dollars per share) | $ / shares | 1.64 | 
| Vested (in dollars per share) | $ / shares | 1.66 | 
| Forfeited (in dollars per share) | $ / shares | 1.96 | 
| Ending Balance (in dollars per share) | $ / shares | $ 1.76 | 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition Gross number of share options (or share units) granted during the period. No definition available. 
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Number of non-vested options outstanding. No definition available. 
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- Definition Number of non-vested options forfeited. No definition available. 
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- Definition Weighted average grant-date fair value of non-vested options forfeited. No definition available. 
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- Definition Weighted average grant-date fair value of non-vested options outstanding. No definition available. 
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- Definition Number of options vested. No definition available. 
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- Definition Weighted average grant-date fair value of options vested. No definition available. 
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- Details 
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