CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 39,984	$ 36,976
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	38,149	21,100
Gains from sale of investments	(55)	0
Share-based compensation expense	25,279	25,724
Operating lease right-of-use assets expense	3,082	1,546
Deferred income tax benefit	(9,438)	(3,267)
Changes in operating assets and liabilities, exclusive of effects of    acquired companies:
Accounts receivable	20,637	49,317
Income tax receivable	19,512	4,533
Prepaid expenses and other current assets	(5,481)	(9,261)
Accounts payable	6,294	(2,292)
Operating lease liabilities	(3,071)	(1,639)
Accrued liabilities	(30,642)	(8,965)
Deferred revenue	(56,551)	(42,069)
Increase in other long-term liabilities	5,842	0
Net cash provided by operating activities	53,541	71,703
Cash flows from investing activities:
Additions to property and equipment	(4,579)	(6,564)
Purchase of marketable security investments	(4,592)	(52,755)
Proceeds and maturities from marketable security investments	22,672	35,031
Investment in software	(7,947)	(3,476)
Cost of acquisitions, net of cash acquired	(116,698)	(12,049)
Other	(29)	119
Net cash used by investing activities	(111,173)	(39,694)
Cash flows from financing activities:
Net borrowings on revolving credit facility	0	0
Payment on term loans	(20,000)	0
Proceeds from issuance of convertible senior notes	0	600,000
Payment of debt issuance costs	0	(6,020)
Proceeds from exercise of stock options	8,045	18,102
Contributions from employee stock purchase plan	3,678	3,038
Net cash (used) provided by financing activities	(8,277)	615,120
Net (decrease) increase in cash and cash equivalents	(65,909)	647,129
Cash and cash equivalents at beginning of period	309,171	603,623
Cash and cash equivalents at end of period	$ 243,262	$ 1,250,752