Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Adoption of ASU 2016-09 (Details) - USD ($) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Jan. 01, 2017 |
Dec. 31, 2016 |
|
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||
Cumulative adjustment to accumulated deficit upon adoption of ASU 2016-09 | $ 98,000 | ||
Excess tax benefit amount booked to income tax provision | 5,300,000 | ||
Income taxes payable, non-current | $ 0 | $ 98,000 | |
Accounting Standards Update 2016-09 | |||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||
Cumulative adjustment to accumulated deficit upon adoption of ASU 2016-09 | $ 98,000 | ||
Income taxes payable, non-current | $ (98,000) |