Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 27,122	$ 7,278
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8,226	5,677
Purchase accounting adjustments to goodwill	0	(23)
Loss on disposal and impairment of property and equipment, net	290	0
Loss on disposal and abandonment of intangible assets	2,103	0
Bond premium amortization	34	594
Stock-based compensation	15,302	11,423
Deferred income taxes	(2,326)	(4,155)
Unrecognized tax benefits	99	(134)
Change in assets and liabilities:
Accounts and notes receivable and contract assets	(51,172)	(26,027)
Inventory	9,033	(19,074)
Prepaid expenses and other assets	(12,081)	(11,252)
Accounts payable, accrued and other liabilities	4,306	3,382
Deferred revenue	31,700	26,460
Net cash provided by (used in) operating activities	32,636	(5,851)
Cash flows from investing activities:
Purchases of investments	(4,331)	(19,950)
Proceeds from maturity/call of investments	10,658	49,633
Purchases of property and equipment	(6,880)	(9,072)
Purchases of intangible assets	(460)	(431)
Business acquisitions	(4,990)	(10,629)
Net cash provided by (used in) investing activities	(6,003)	9,551
Cash flows from financing activities:
Net proceeds from equity offering	233,993	0
Proceeds from options exercised	713	1,255
Income and payroll tax payments for net-settled stock awards	(11,973)	(2,830)
Payment of contingent consideration for a business acquisition	(575)	0
Net cash provided by (used in) financing activities	222,158	(1,575)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(381)	703
Net increase in cash, cash equivalents and restricted cash	248,410	2,828
Cash, cash equivalents and restricted cash, beginning of period	78,438	43,969
Cash, cash equivalents and restricted cash, end of period	326,848	46,797
Supplemental disclosures:
Cash and cash equivalents	324,371	43,471
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	78,438	43,969
Cash paid for income taxes, net of refunds	7,957	12,206
Non-cash transactions
Property and equipment purchases in accounts payable and accrued liabilities	1,114	556
Non-cash purchase consideration related to business combinations	$ 12,508	$ 1,007