Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income	$ 15,817	$ 39,243
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	43,903	39,525
Loss on disposal of property and equipment	0	436
Share-based compensation expense	33,034	25,175
Deferred income taxes	(3,643)	4,023
Amortization of operating lease right-of-use assets	7,692	7,917
Amortization of debt issuance costs	754	1,718
Amortization of discount on convertible senior notes	249	0
Changes in operating assets and liabilities:
Accounts receivable and unbilled receivables	29,653	(7,716)
Inventories	4,570	(7,015)
Prepaid expenses	(6,272)	(1,341)
Other current assets	(6,617)	974
Investment in sales-type leases	(3,273)	(5,120)
Prepaid commissions	2,213	909
Other long-term assets	(4,023)	3,944
Accounts payable	(8,659)	10,316
Accrued compensation	(8,377)	(8,161)
Accrued liabilities	3,281	5,262
Deferred revenues	8,827	3,900
Operating lease liabilities	(7,764)	(7,887)
Other long-term liabilities	8,057	4,086
Net cash provided by operating activities	109,422	110,188
Investing Activities
Software development for external use	(25,909)	(34,129)
Purchases of property and equipment	(17,265)	(12,632)
Net cash used in investing activities	(43,174)	(46,761)
Financing Activities
Proceeds from revolving credit facility	150,000	0
Repayment of debt and revolving credit facility	(200,000)	(60,000)
Payments for debt issuance costs for revolving credit facility	(550)	0
Proceeds from issuance of convertible senior notes, net of issuance costs	559,665	0
Purchase of convertible note hedge	(100,625)	0
Proceeds from sale of warrants	51,290	0
At the market equity offering, net of offering costs	0	37,806
Proceeds from issuances under stock-based compensation plans	33,226	35,029
Employees’ taxes paid related to restricted stock units	(4,101)	(5,790)
Stock repurchases	(53,035)	0
Net cash provided by financing activities	435,870	7,045
Effect of exchange rate changes on cash and cash equivalents	(157)	(387)
Net increase in cash and cash equivalents	501,961	70,085
Cash and cash equivalents at beginning of period	127,210	67,192
Cash and cash equivalents at end of period	629,171	137,277
Supplemental disclosure of non-cash activities
Unpaid purchases of property and equipment	319	756
Transfers between inventory and property and equipment, net	0	1,549
Transfers from prepaid expenses to property and equipment	0	3,313
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 1,559	$ 957