Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
OPERATING ACTIVITIES:
Net income	$ 479,936	$ 178,084
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other	16,782	12,705
Stock-based compensation expense	7,432	5,828
Amortization of deferred financing costs	101	101
Accretion of interest on deferred consideration	982	1,451
Net change in operating lease right-of-use assets and liabilities	9,351	794
Change in deferred tax assets and liabilities	(89)	446
Changes in assets and liabilities:
Accounts receivable	(191,452)	427,052
Inventories	17,355	(61,134)
Prepaid expenses and other current and non-current assets	(7,291)	(13,811)
Accounts payable	52,592	(3,860)
Accrued payroll and related expenses	(10,944)	(16,054)
Income taxes payable	138,384	41,386
Other current and non-current liabilities	(12,167)	12,469
Net cash provided by operating activities:	500,972	585,457
INVESTING ACTIVITIES:
Acquisitions of property, equipment, investments and intangibles	(22,402)	(78,291)
Proceeds from government assistance allocated to fixed assets	0	13,722
Purchases of marketable securities	(15,937)	0
Proceeds from sale of marketable securities	13,669	0
Net cash used for investing activities:	(24,670)	(64,569)
FINANCING ACTIVITIES:
Proceeds from issuance of common stock	3,527	4,373
Payments on finance lease obligation	(91)	(62)
Payments of tax withholdings related to vesting of stock-based awards	(6,815)	(33,929)
Principal payments of acquisition contingent consideration	(29)	(30)
Net cash used for financing activities:	(3,408)	(29,648)
Effect of exchange rates on cash	(109)	(129)
Net increase in cash and cash equivalents	472,785	491,111
Cash and cash equivalents, beginning of period	802,751	489,941
Cash and cash equivalents, end of period	1,275,536	981,052
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Purchase of property, equipment and intangibles by incurring current liabilities	13,714	7,284
Capital expenditures to be reimbursed under a government contract	0	12,622
Reduction of other current liabilities upon issuance of restricted share units	$ 2,850	$ 2,001