Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net income	$ 140,104	$ 134,085
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	51,342	53,038
Amortization of premium (discount) on marketable securities	4,446	1,763
Write-down for excess and obsolete inventories, net	5,890	5,570
Stock-based compensation expense	24,303	22,781
Allowance for doubtful accounts	(396)	883
Change in fair value of business acquisition liabilities	(2,043)	14,336
Change in deferred income taxes	(17,014)	(3,131)
(Gain)/loss on disposal of assets, net	241	383
Payment of business acquisition related liabilities	(2,021)
(Increase)/decrease in:
Accounts receivable	(46,200)	(19,928)
Inventories	(48,650)	(9,161)
Prepaid expenses and other assets	(6,866)	(794)
Increase/(decrease) in:
Accounts payable	10,407	2,521
Accrued expenses and other liabilities	1,660	7,500
Income taxes payable/receivable	(710)	(9,825)
Net cash provided by/(used in) operating activities	114,493	200,021
Cash flows from investing activities:
Purchases of marketable securities	(322,100)	(347,057)
Maturities of marketable securities	239,126	171,886
Sales of marketable securities	89,978	82,882
Purchases of property and equipment	(55,707)	(39,853)
Acquisition of businesses, net of cash acquired and purchases of intangible and other assets	(1,175)
Net cash provided by/(used in) investing activities	(49,878)	(132,142)
Cash flows from financing activities:
Payment of business acquisition liabilities	(5,288)	(4,763)
Proceeds from exercise of stock options	26,228	59,933
Repurchase of common stock	(144,493)
Net cash provided by/(used in) financing activities	(123,553)	55,170
Effect of foreign exchange rates on cash	92	(570)
Net increase/(decrease) in cash and cash equivalents	(58,846)	122,479
Cash and cash equivalents at beginning of period	193,069	239,397
Cash and cash equivalents at end of period	134,223	361,876
Supplemental disclosures of cash flow information:
Income taxes paid	58,301	39,450
Purchases of property and equipment included in accounts payable and accrued expenses	$ 5,341	$ 3,491