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Summary of Significant Accounting Policies - Recently Issued and Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2017 | Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Cumulative effect of adoption of ASU 2016-09 | $ 0 |
Accounting Standards Update 2016-09 |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Deferred tax assets related to stock-based compensation costs |  | $ 17,900
Additional Paid-in Capital |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Cumulative effect of adoption of ASU 2016-09 | $ 1,461 |

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