Balance Sheet Components Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Notes To Financial Statements [Abstract]
Capitalized commissions	$ 7,681	$ 5,515
Other long-term assets	5,831	4,821
Security deposits	3,721	3,557
Loan receivable	0	30,000
Total other assets	$ 17,233	$ 43,893