Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income	$ 77,849	$ 32,194	$ 61,338
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	72,990	61,067	53,559
Loss on disposal of property and equipment	433	267	445
Share-based compensation expense	53,160	44,697	34,049
Deferred income taxes	(3,272)	(6,546)	(1,339)
Amortization of operating lease right-of-use assets	11,941	10,528	10,562
Amortization of debt issuance costs	3,440	1,597	2,204
Amortization of discount on convertible senior notes	18,608	4,766	0
Changes in operating assets and liabilities:
Accounts receivable and unbilled receivables	(40,973)	36,842	(21,540)
Inventories	(25,695)	12,359	(8,123)
Prepaid expenses	(5,678)	(2,081)	2,909
Other current assets	2,801	(6,408)	(2,010)
Investment in sales-type leases	3,346	(2,882)	(3,699)
Prepaid commissions	(6,876)	(8,057)	(2,719)
Other long-term assets	(3,258)	(7,675)	4,528
Accounts payable	29,084	(6,300)	7,893
Accrued compensation	12,312	11,595	2,495
Accrued liabilities	34,859	4,374	3,045
Deferred revenues	24,179	7,620	5,445
Operating lease liabilities	(12,503)	(9,543)	(10,040)
Other long-term liabilities	(14,938)	7,456	6,006
Net cash provided by operating activities	231,809	185,870	145,008
Investing Activities
Software development for external use	(29,368)	(32,024)	(45,770)
Purchases of property and equipment	(28,967)	(22,842)	(15,894)
Business acquisitions, net of cash acquired	(354,163)	(225,000)	0
Net cash used in investing activities	(412,498)	(279,866)	(61,664)
Financing Activities
Proceeds from revolving credit facility	0	150,000	0
Repayment of debt and revolving credit facility	0	(200,000)	(90,000)
Payments for debt issuance costs for revolving credit facility	0	(550)	(2,321)
Proceeds from issuance of convertible senior notes, net of issuance costs	0	559,665	0
Purchase of convertible note hedge	0	(100,625)	0
Proceeds from sale of warrants	0	51,290	0
At the market equity offering, net of offering costs	0	0	37,806
Proceeds from issuances under stock-based compensation plans	67,348	54,270	40,706
Employees’ taxes paid related to restricted stock units	(16,286)	(8,738)	(9,670)
Stock repurchases	0	(53,035)	0
Change in customer funds, net	(3,699)	3,992	0
Net cash provided by (used in) financing activities	47,363	456,269	(23,479)
Effect of exchange rate changes on cash and cash equivalents	(974)	437	153
Net increase (decrease) in cash, cash equivalents, and restricted cash	(134,300)	362,710	60,018
Cash, cash equivalents, and restricted cash at beginning of period	489,920	127,210	67,192
Cash, cash equivalents, and restricted cash at end of period	355,620	489,920	127,210
Reconciliation of cash, cash equivalents, and restricted cash to the Consolidated Balance Sheets:
Cash and cash equivalents	349,051	485,928	127,210
Restricted cash	6,569	3,992	0
Cash, cash equivalents, and restricted cash at end of period	355,620	489,920	127,210
Supplemental cash flow information
Cash paid for interest	1,917	522	3,582
Income taxes paid (refunds received), net	(1,733)	10,343	7,761
Supplemental disclosure of non-cash activities
Unpaid purchases of property and equipment	883	405	913
Transfers between inventory and property and equipment, net	1,876	0	1,552
Transfers from prepaid expenses to property and equipment	0	0	3,313
Balance transfer from term loan to revolving credit facility	$ 0	$ 0	$ 80,000