Organization and Summary of Significant Accounting Policies - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Short-term unbilled receivables - included in accounts receivable and unbilled receivables	$ 9,191	$ 4,590
Other long-term assets	74,613	49,316
Total contract assets	25,672	14,065
Short-term deferred revenues	81,835	78,774
Long-term deferred revenues	10,582	10,623
Total contract liabilities	92,417	89,397
Long-term Contract with Customer
Disaggregation of Revenue [Line Items]
Other long-term assets	$ 16,481	$ 9,475