CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 03, 2015	Mar. 28, 2014
Cash flows from operating activities:
Net loss	$ (2,657)us-gaap_NetIncomeLoss	$ (5,410)us-gaap_NetIncomeLoss
Adjustments to reconcile net loss to net cash provided by operating activities:
Amortization of intangibles	1,907us-gaap_AmortizationOfIntangibleAssets	6,666us-gaap_AmortizationOfIntangibleAssets
Depreciation	3,493us-gaap_Depreciation	4,227us-gaap_Depreciation
Stock-based compensation	4,134us-gaap_ShareBasedCompensation	3,807us-gaap_ShareBasedCompensation
Loss on impairment of long-term investment	2,505	0
Deferred income taxes, net	0us-gaap_DeferredIncomeTaxExpenseBenefit	3,510us-gaap_DeferredIncomeTaxExpenseBenefit
Provision for excess and obsolete inventories	454us-gaap_InventoryWriteDown	722us-gaap_InventoryWriteDown
Allowance for doubtful accounts, returns and discounts	(367)us-gaap_ProvisionForDoubtfulAccounts	(536)us-gaap_ProvisionForDoubtfulAccounts
Excess tax benefits from stock-based compensation	(120)	(185)
Other non-cash adjustments, net	154us-gaap_OtherNoncashIncomeExpense	462us-gaap_OtherNoncashIncomeExpense
Changes in assets and liabilities:
Accounts receivable	(1,353)	(1,927)
Inventories	775us-gaap_IncreaseDecreaseInInventories	5,900us-gaap_IncreaseDecreaseInInventories
Prepaid expenses and other assets	(13,062)	(6,671)
Accounts payable	3,380	(2,533)
Deferred revenue	10,105	6,382
Income taxes payable	(501)	278
Accrued and other liabilities	(6,819)	(3,447)
Net cash provided by operating activities	2,028	11,245
Cash flows from investing activities:
Purchases of investments	0us-gaap_PaymentsToAcquireInvestments	(14,084)us-gaap_PaymentsToAcquireInvestments
Proceeds from maturities of investments	9,497	15,382
Purchases of property and equipment	(3,651)	(3,431)
Purchases of long-term investments	85	0
Net cash provided by (used in) investing activities	5,761	(2,133)
Cash flows from financing activities:
Payments for repurchase of common stock	(5,182)	(29,075)
Proceeds from (repurchases of) common stock issued to employees	4,032	(1,377)
Excess tax benefits from stock-based compensation	120	185
Net cash used in financing activities	(1,030)	(30,267)
Effect of exchange rate changes on cash and cash equivalents	(135)	18
Net increase (decrease) in cash and cash equivalents	6,624	(21,137)
Cash and cash equivalents at beginning of period	73,032	90,329
Cash and cash equivalents at end of period	$ 79,656	$ 69,192

Name:	us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.