Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2004	Dec. 31, 2002	Mar. 31, 2021
Business Acquisition [Line Items]
Purchase obligation			$ 4.5
Minimum
Business Acquisition [Line Items]
Remaining lease term			1 year
Maximum
Business Acquisition [Line Items]
Remaining lease term			9 years
Travel Zoo Com Corporation
Business Acquisition [Line Items]
Period for receiving shares under merger	2 years	2 years
Number of shares exchanged under merger (in shares)		1