Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 169,352	$ 121,488
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	20,376	13,785
Amortization of premium on available-for-sale securities	3,231	1,984
Gain on deferred compensation plan investments	(2,640)	(1,420)
Deferred taxes, net	1,004	3,400
Stock-based compensation expense	92,282	62,581
Other	(8)	15
Changes in operating assets and liabilities:
Accounts receivable	(13,033)	(40,826)
Inventories	(50,968)	(20,533)
Other assets	(14,051)	(6,376)
Accounts payable	30,032	19,811
Accrued compensation and related benefits	30,030	21,780
Income tax liabilities	4,088	(1,805)
Other accrued liabilities	22,109	14,271
Net cash provided by operating activities	291,804	188,155
Cash flows from investing activities:
Purchases of property and equipment	(76,849)	(44,129)
Purchases of short-term investments	(354,171)	(270,797)
Proceeds from maturities and sales of short-term investments	94,192	182,355
Proceeds from sales of long-term investments	400	250
Contributions to deferred compensation plan, net	(1,917)	(1,116)
Purchases of intangible assets	(793)	0
Net cash used in investing activities	(339,138)	(133,437)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(2,049)	(4,437)
Proceeds from common stock issued under the employee equity incentive plan	15,147	16,457
Proceeds from common stock issued under the employee stock purchase plan	4,670	3,819
Dividends and dividend equivalents paid	(80,725)	(65,477)
Net cash used in financing activities	(62,957)	(49,638)
Effect of change in exchange rates	1,431	1,432
Net increase (decrease) in cash, cash equivalents and restricted cash	(108,860)	6,512
Cash, cash equivalents and restricted cash, beginning of period	335,071	173,076
Cash, cash equivalents and restricted cash, end of period	226,211	179,588
Supplemental disclosures for cash flow information:
Cash paid for taxes	16,217	1,036
Non-cash investing and financing activities:
Liability accrued for property and equipment purchases	7,144	9,355
Liability accrued for dividends and dividend equivalents	$ 31,911	$ 26,429