Leases - Lease Costs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Total operating lease costs	$ 2,144
Cost of revenue
Lessee, Lease, Description [Line Items]
Total operating lease costs	200
Sales and marketing
Lessee, Lease, Description [Line Items]
Total operating lease costs	439
Technology and development
Lessee, Lease, Description [Line Items]
Total operating lease costs	871
General and administrative
Lessee, Lease, Description [Line Items]
Total operating lease costs	$ 634