Commitments and Contingencies - Reorganization (Details) - Employee Severance [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2019	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Severance costs		$ 4,600
Severance costs	$ 3,300	7,871
Restructuring Reserve [Roll Forward]
Beginning balance	0	0
Expense	$ 3,300	7,871
Cash Payments		(3,180)
Ending balance		4,691
Sales and marketing
Restructuring Cost and Reserve [Line Items]
Severance costs		400
Technology and development
Restructuring Cost and Reserve [Line Items]
Severance costs		900
General and administrative
Restructuring Cost and Reserve [Line Items]
Severance costs		$ 3,300