Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 121,488	$ 76,402
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,785	10,817
(Gain) loss on disposal and sale of property and equipment, net	15	(282)
Amortization of premium on available-for-sale securities	1,984	384
Gain on deferred compensation plan investments	(1,420)	(2,630)
Deferred taxes, net	3,400	(18)
Stock-based compensation expense	62,581	60,019
Changes in operating assets and liabilities:
Accounts receivable	(40,826)	(3,048)
Inventories	(20,533)	754
Other assets	(6,376)	(5,849)
Accounts payable	19,811	7,173
Accrued compensation and related benefits	21,780	10,328
Income tax liabilities	(1,805)	(6,186)
Other accrued liabilities	14,271	7,453
Net cash provided by operating activities	188,155	155,317
Cash flows from investing activities:
Purchases of property and equipment	(44,158)	(87,129)
Acquisition of in-place leases	0	(981)
Purchases of short-term investments	(270,797)	(106,409)
Proceeds from maturities and sales of short-term investments	182,355	98,814
Proceeds from sales of long-term investments	250	125
Proceeds from sales of property and equipment	29	9,268
Contributions to deferred compensation plan, net	(1,116)	(1,797)
Net cash used in investing activities	(133,437)	(88,109)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(4,437)	(204)
Proceeds from common stock issued under the employee equity incentive plan	16,457	14,561
Proceeds from common stock issued under the employee stock purchase plan	3,819	3,277
Dividends and dividend equivalents paid	(65,477)	(48,641)
Net cash used in financing activities	(49,638)	(31,007)
Effect of change in exchange rates	1,432	(2,516)
Net increase in cash, cash equivalents and restricted cash	6,512	33,685
Cash, cash equivalents and restricted cash, beginning of period	173,076	172,818
Cash, cash equivalents and restricted cash, end of period	179,588	206,503
Supplemental disclosures for cash flow information:
Cash paid for taxes	1,036	9,472
Non-cash investing and financing activities:
Liability accrued for property and equipment purchases	9,355	4,969
Liability accrued for dividends and dividend equivalents	$ 26,429	$ 20,866