Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 242,023	$ 164,375	$ 108,839
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	28,699	19,186	14,867
Amortization of premium on available-for-sale securities	4,674	2,979	729
Gain on deferred compensation plan investments	(4,563)	(4,592)	(3,806)
Deferred taxes, net	(2,772)	(1,627)	(577)
Stock-based compensation expense	123,479	85,551	78,699
Other	110	(1,072)	(259)
Changes in operating assets and liabilities:
Accounts receivable	(37,976)	(14,123)	2,512
Inventories	(102,323)	(29,503)	8,865
Other assets	(15,311)	(3,003)	(10,204)
Accounts payable	32,926	10,410	3,048
Accrued compensation and related benefits	16,536	18,524	7,496
Income tax liabilities	11,771	747	(1,355)
Other accrued liabilities	22,737	19,951	7,449
Net cash provided by operating activities	320,010	267,803	216,303
Cash flows from investing activities:
Purchases of property and equipment	(94,445)	(55,639)	(95,806)
Sales of property and equipment	25	29	9,268
Purchases of short-term investments	(394,886)	(334,947)	(212,562)
Maturities and sales of short-term investments	113,255	357,092	135,801
Purchases of long-term investments	0	(3,316)	0
Sales of long-term investments	500	300	250
Contributions to deferred compensation plan, net	(2,542)	(2,696)	(3,082)
Purchases of intangible assets	(793)	0	(981)
Net cash used in investing activities	(378,886)	(39,177)	(167,112)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(2,834)	(5,357)	(683)
Proceeds from common stock issued under the employee equity incentive plan	17,322	18,767	16,650
Proceeds from common stock issued under the employee stock purchase plan	4,670	3,819	3,277
Dividends and dividend equivalents paid	(109,364)	(88,786)	(67,294)
Net cash used in financing activities	(90,206)	(71,557)	(48,050)
Effect of change in exchange rates	3,400	4,926	(883)
Net increase (decrease) in cash, cash equivalents and restricted cash	(145,682)	161,995	258
Cash, cash equivalents and restricted cash, beginning of period	335,071	173,076	172,818
Cash, cash equivalents and restricted cash, end of period	189,389	335,071	173,076
Supplemental disclosures for cash flow information:
Cash paid for taxes	21,148	1,405	10,700
Non-cash investing and financing activities:
Liability accrued for property and equipment purchases	17,877	7,839	7,803
Liability accrued for dividends and dividend equivalents	$ 33,059	$ 27,507	$ 21,955