Summary of Significant Accounting Policies - Stock-Based Compensation Expense (Details)
|12 Months Ended|
Dec. 31, 2019
|Accounting Policies [Abstract]|
|Compensation expense recognized period||6 years|
Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef