CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net Income (Loss)	$ 13,306	$ 10,265
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	20,169	15,356
Depreciation	9,971	9,388
Amortization of intangible assets	31,436	26,045
Non-cash interest expense and amortization of convertible debt issuance costs	5,324	5,025
Excess tax benefits from stock-based compensation, Operating Activities	0	(927)
Deferred income taxes	(4,108)	(4,157)
(Gain) loss from disposal of property, plant and equipment	169	(29)
Effect of Exchange Rate on assumed cash liability from acquisition	0	985
Change in operating assets and liabilities, net of impact of acquisitions:
Accounts receivable	(23,656)	333
Prepaid expenses and other assets	6,824	(3,143)
Inventories	617	(744)
Accounts payable	(2,795)	2,302
Accrued salaries and benefits and other liabilities	(2,658)	(4,772)
Deferred revenue	3,248	7,532
Net cash provided by operating activities	57,847	61,489
Cash flows from investing activities:
Purchases of property, plant and equipment	(5,444)	(4,750)
Acquisition of intangible assets	(120)	0
Purchases of marketable securities	0	54,869
Maturities of marketable securities	32,048	85,746
Proceeds from sale of marketable securities	4,450	50,546
Proceeds from sale of property, plant, and equipment	28	0
Acquisitions of businesses, net of cash acquired	0	(202,523)
Net cash provided by (used in) investing activities	30,962	(125,850)
Cash flows from financing activities:
Excess tax benefits from stock-based compensation, Financing Activities	0	927
Proceeds received from issuance of common stock under employee stock plans	10,792	12,277
Principal payments against lease financing obligation	(625)	(476)
Payments Related to Tax Withholding for Share-based Compensation	(3,525)	(1,861)
Payments for Repurchase of Common Stock	(50,036)	0
Net cash provided by (used in) financing activities	(43,394)	10,867
Effect of Exchange Rate on Cash and Cash Equivalents	1,636	(791)
Net increase (decrease) in cash and cash equivalents	47,051	(54,285)
Cash and cash equivalents at beginning of period	135,294	143,764
Cash and cash equivalents at end of period	182,345	89,479
Non-cash investing and financing activities during the period:
Assumed cash liability from acquisition	0	10,779
Property, plant and equipment received and accrued in accounts payable and other liabilities	$ 1,294	$ 1,344