CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income (loss)	$ 37,027	$ (10,937)	$ 8,779
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Amortization of intangibles	27,329	29,204	30,420
Depreciation	16,641	15,195	13,867
Stock-based compensation	16,089	18,926	20,913
Gain on sale of discontinued operations, net of tax	(14,663)	0	0
Loss on impairment of fixed assets	149	0	0
Net (gain) loss on disposal of fixed assets	95	(36)	671
Deferred income taxes	(8,537)	(4,969)	(361)
Provision for doubtful accounts and sales returns	960	3,602	3,235
Provision for excess and obsolete inventories	3,475	3,377	3,936
Excess tax benefits from stock-based compensation	(141)	(121)	(1,955)
Other non-cash adjustments, net	2,098	1,006	801
Changes in assets and liabilities:
Accounts receivable	9,908	20,368	(11,477)
Inventories	13,290	3,003	(16,588)
Prepaid expenses and other assets	1,807	(2,684)	7,924
Accounts payable	(3,363)	(5,201)	4,750
Deferred revenues	(1,922)	1,334	(13,470)
Income taxes payable	(40,546)	1,535	(6,843)
Accrued and other liabilities	(5,937)	(2,789)	575
Net cash provided by operating activities	53,759	70,813	45,177
Cash flows from investing activities:
Purchases of investments	(78,764)	(133,778)	(107,544)
Proceeds from maturities of investments	63,034	57,484	28,733
Proceeds from sales of investments	37,890	41,354	30,999
Purchases of property and equipment	(14,581)	(12,609)	(17,269)
Proceeds from sale of discontinued operations, net of selling costs	43,515	0	0
Other acquisitions	0	0	(250)
Net cash provided by (used in) investing activities	51,094	(47,549)	(65,331)
Cash flows from financing activities:
Proceeds from issuance of common stock, net	5,186	4,819	12,701
Payments for repurchase of common stock	(116,529)	(22,639)	0
Excess tax benefits from stock-based compensation	141	121	1,955
Net cash (used in) provided by financing activities	(111,202)	(17,699)	14,656
Effect of exchange rate changes on cash and cash equivalents	8	122	(52)
Net increase (decrease) in cash and cash equivalents	(6,341)	5,687	(5,550)
Cash and cash equivalents at beginning of period	96,670	90,983	96,533
Cash and cash equivalents at end of period	90,329	96,670	90,983
Supplemental disclosures of cash flow information:
Income tax payments, net	4,341	5,051	7,597
Supplemental schedule of non-cash investing activity:
Net increase in accrued purchases of property and equipment	$ 321	$ 113	$ 0