Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Operating Activities
Net income	$ 68,446	$ 51,944
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation of property and equipment	11,781	11,068
Amortization of other intangible assets and other assets	33,322	20,531
Amortization of debt discount and debt issuance costs	9,578	6,984
Stock-based compensation expense	36,893	33,007
Deferred income taxes	(2,994)	(5,703)
Changes in operating assets and liabilities:
Accounts receivable	2,518	(1,587)
Inventories	5,066	(13,196)
Prepaid expenses and other assets	6,349	23,506
Accounts payable	8,675	1,746
Other current liabilities and income taxes	(23,814)	9,296
Deferred income, deferred revenue and returns liability	(2,816)	11,039
Other non-current liabilities	(7,878)	(7,269)
Net cash provided by operating activities	145,126	141,366
Investing Activities
Purchases of available-for-sale investments	(253,973)	(471,938)
Sales and maturities of available-for-sale investments	371,885	143,765
Purchases of property and equipment	(18,267)	(10,494)
Purchases of other assets	(9,088)	(2,622)
Acquisitions of business, net of cash acquired	(239,729)	(13,658)
Net cash used in investing activities	(149,172)	(354,947)
Financing Activities
Proceeds from issuance of long-term debt, net		389,468
Payments on debt		(72,500)
Repurchases of common stock	(24,272)
Payment of taxes withheld for vested stock awards	(18,927)	(14,870)
Proceeds from the issuance of common stock	6,585	6,836
Payment of acquisition-related contingent consideration	(3,380)
Net cash provided by (used in) financing activities	(39,994)	308,934
Increase (decrease) in cash and cash equivalents	(44,040)	95,353
Cash and cash equivalents at beginning of period	269,366	141,106
Cash and cash equivalents at end of period	$ 225,326	$ 236,459