Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 76,402	$ 77,630
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,817	9,058
Gain on disposal and sale of property and equipment, net	(282)	0
Amortization of premium on available-for-sale securities	384	1,122
Gain on deferred compensation plan investments	(2,630)	(949)
Deferred taxes, net	(18)	3,169
Stock-based compensation expense	60,019	45,765
Changes in operating assets and liabilities:
Accounts receivable	(3,048)	(22,752)
Inventories	754	(37,496)
Other assets	(5,849)	(665)
Accounts payable	7,173	5,978
Accrued compensation and related benefits	10,328	7,838
Other accrued liabilities	7,453	4,635
Income tax liabilities	(6,186)	528
Net cash provided by operating activities	155,317	93,861
Cash flows from investing activities:
Purchases of property and equipment	(87,129)	(18,057)
Acquisition of in-place leases	(981)	0
Purchases of short-term investments	(106,409)	(86,021)
Proceeds from maturities and sales of short-term investments	98,814	83,679
Proceeds from sales of long-term investments	125	0
Proceeds from sales of property and equipment	9,268	0
Contributions to deferred compensation plan, net	(1,797)	(1,396)
Net cash used in investing activities	(88,109)	(21,795)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(204)	0
Proceeds from common stock issued under employee equity incentive plans	14,561	9,684
Proceeds from common stock issued under employee stock purchase plan	3,277	3,028
Dividends and dividend equivalents paid	(48,641)	(34,381)
Net cash used in financing activities	(31,007)	(21,669)
Effect of change in exchange rates	(2,516)	(2,062)
Net increase in cash, cash equivalents and restricted cash	33,685	48,335
Cash, cash equivalents and restricted cash, beginning of period	172,818	82,874
Cash, cash equivalents and restricted cash, end of period	206,503	131,209
Supplemental disclosures for cash flow information:
Cash paid for taxes	9,472	6,388
Non-cash investing and financing activities:
Liability accrued for property and equipment purchases	4,969	1,563
Liability accrued for dividends and dividend equivalents	$ 20,866	$ 15,397