Other Balance Sheet Items Other balance Sheet items (Other long-term assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Prepaid registry fees, noncurent	$ 7,997	$ 7,753
Nontrade Receivables, Noncurrent	969	6,927
Operating Lease, Right-of-Use Asset	11,277	9,133
Restricted Cash and Investments, Noncurrent	9,407	9,405
Prepaid Expense and Other Assets, Noncurrent	8,308	6,594
Total other long-term assets	$ 37,958	$ 39,812
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets