Summary of Significant Accounting Policies - Property and Equipment Useful Lives (Details)	12 Months Ended
	Dec. 31, 2019
Furniture and Fixtures | Minimum
Property and equipment
Property and equipment estimated useful life	5 years
Furniture and Fixtures | Maximum
Property and equipment
Property and equipment estimated useful life	7 years
Computer hardware | Minimum
Property and equipment
Property and equipment estimated useful life	3 years
Computer hardware | Maximum
Property and equipment
Property and equipment estimated useful life	5 years
Software | Minimum
Property and equipment
Property and equipment estimated useful life	3 years
Software | Maximum
Property and equipment
Property and equipment estimated useful life	5 years