CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 203,011	$ 210,061	$ 184,213
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	27,409	24,815	19,968
Amortization of intangibles	15,993	17,459	21,994
Amortization of premium and discount on investments, net	(11,603)	(6,461)	(373)
Impairment of minority investments	0	6,962	0
Stock-based compensation to employees	22,335	28,380	34,871
Stock-based compensation to Board of Directors and Scientific Advisory Board	1,774	1,566	1,404
Deferred income tax (benefit) expense	(3,766)	(26,946)	1,748
Retirement plan expense, net of benefit payments	3,129	5,276	8,875
Decrease (increase) in assets:
Accounts receivable	(47,186)	14,975	(25,378)
Inventory	7,425	(49,060)	(42,569)
Other current assets	(41,574)	(24,843)	(202)
Other assets	4,450	25,971	(32,369)
Increase (decrease) in liabilities:
Accounts payable and accrued expenses	4,047	3,338	1,902
Other current liabilities	(21,481)	20,917	2,105
Deferred revenue	(4,159)	(93,203)	(5,220)
Other liabilities	(5,027)	(32,392)	20,136
Net cash provided by operating activities	154,777	126,815	191,105
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(59,792)	(42,497)	(43,161)
Purchase of intangibles	(66,563)	(4,709)	(394)
Purchases of investments	(531,103)	(701,993)	(642,180)
Proceeds from sale and maturity of investments	574,165	468,456	227,984
Net cash used in investing activities	(83,293)	(280,743)	(457,751)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	2,012	1,570	1,507
Payment of withholding taxes related to stock-based compensation to employees	(8,206)	(9,209)	(14,949)
Cash dividends paid	(66,735)	(56,996)	(37,931)
Net cash used in financing activities	(72,929)	(64,635)	(51,373)
DECREASE IN CASH AND CASH EQUIVALENTS	(1,445)	(218,563)	(318,019)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	93,430	311,993	630,012
CASH AND CASH EQUIVALENTS, END OF YEAR	$ 91,985	$ 93,430	$ 311,993