Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 37,729	$ 30,518	$ 9,756
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	51,350	51,511	58,362
Loss on disposal of fixed assets	133	512	35
Gain related to contingent liability	0	0	(600)
Share-based compensation expense	28,885	21,857	19,500
Income tax benefits from employee stock plans	0	11	1,703
Deferred income taxes	(5,705)	(31,365)	(5,111)
Amortization of debt financing fees	2,292	1,590	1,590
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable and unbilled receivables	(6,192)	(40,598)	9,932
Inventories	(6,763)	(26,840)	(3,362)
Prepaid expenses	(308)	(4,920)	(386)
Other current assets	1,170	(2,074)	(1,093)
Investment in sales-type leases	(1,680)	6,625	(9,639)
Prepaid commissions	(4,711)	(3,966)	(7,150)
Other long-term assets	(7,077)	(1,373)	(5,133)
Accounts payable	(9,154)	19,709	(4,963)
Accrued compensation	14,419	519	(2,052)
Accrued liabilities	8,223	4,383	(3,287)
Deferred revenues	3,020	(2,334)	(1,938)
Other long-term liabilities	(1,665)	1,069	(6,264)
Net cash provided by operating activities	103,966	24,834	49,900
Investing Activities
Purchase of intangible assets, intellectual property, and patents	0	(160)	(1,372)
Software development for external use	(30,677)	(15,040)	(14,348)
Purchases of property and equipment	(23,697)	(15,341)	(13,445)
Business acquisitions, net of cash acquired	0	(4,446)	(312,158)
Net cash used in investing activities	(54,374)	(34,987)	(341,323)
Financing Activities
Proceeds from debt, net	0	56,894	287,051
Repayment of debt and revolving credit facility	(77,000)	(102,500)	(34,500)
Payment for contingent consideration	0	(2,400)	(3,000)
Proceeds from issuances under share-based compensation plans	30,611	30,121	17,691
Employees’ taxes paid related to restricted stock units	(6,775)	(5,892)	(3,490)
At the market offering, net of offering costs	39,567	13,900	0
Net cash provided by (used in) financing activities	(13,597)	(9,877)	263,752
Effect of exchange rate changes on cash and cash equivalents	(1,227)	(2,034)	(58)
Net increase (decrease) in cash and cash equivalents	34,768	(22,064)	(27,729)
Cash and cash equivalents at beginning of period	32,424	54,488	82,217
Cash and cash equivalents at end of period	67,192	32,424	54,488
Supplemental cash flow information
Cash paid for interest	7,487	6,550	5,344
Cash paid for taxes, net of refunds	3,489	7,780	11,091
Supplemental disclosure of non-cash investing activities
Non-cash activity business acquisition	0	3,400	0
Unpaid property and equipment purchases	1,123	1,691	246
Transfers between inventory and property and equipment, net	$ 2,032	$ 0	$ 0