Balance Sheet Account Details

Short-Term Investments

The following is a summary of short-term investments (in thousands):



	September 29, 2013									December 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available-for-sale securities:
Debt securities in government sponsored entities	$	71,355	$	26	$	(38	)	$	71,343	$	314,638	$	251	$	(16	)	$	314,873
Corporate debt securities	234,587		327		(251		)	234,663		471,989		1,059		(187		)	472,861
U.S. Treasury securities	30,086		63		—			30,149		128,256		233		—			128,489
Total available-for-sale securities	$	336,028	$	416	$	(289	)	$	336,155	$	914,883	$	1,543	$	(203	)	$	916,223

As of September 29, 2013, the Company had 72 available-for-sale securities in a gross unrealized loss position, all of which had been in such position for less than 12 months. There were no impairments considered other-than-temporary as it is more likely than not the Company will hold the securities until maturity or until the cost basis is recovered.

The following table shows the fair values and the gross unrealized losses of the Company’s available-for-sale securities that were in an unrealized loss position as of September 29, 2013 and December 30, 2012, aggregated by investment category (in thousands):



	September 29, 2013					December 30, 2012
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Debt securities in government sponsored entities	$	26,272	$	(38	)	$	28,176	$	(16	)
Corporate debt securities	88,299		(251		)	130,224		(187		)
Total	$	114,571	$	(289	)	$	158,400	$	(203	)

Realized gains and losses are determined based on the specific identification method and are reported in interest income. Gross realized gains and losses on sales of available-for-sale securities were immaterial for all periods presented.

Contractual maturities of available-for-sale debt securities as of September 29, 2013 were as follows (in thousands):



	Estimated Fair Value
Due within one year	$	176,443
After one but within five years	159,712
Total	$	336,155

Cost-Method Investments

As of September 29, 2013 and December 30, 2012, the aggregate carrying amounts of the Company’s cost-method investments in non-publicly traded companies were $56.5 million and $56.3 million, respectively, which were included in other assets on the consolidated balance sheets. During the three months ended March 31, 2013, the Company sold a cost-method investment and recognized a $6.1 million gain. The Company assesses all cost-method investments for impairment quarterly. No impairment loss was recorded during the three and nine months ended September 29, 2013 or September 30, 2012. The Company does not reassess the fair value of cost-method investments if there are no identified events or changes in circumstances that may have a significant adverse effect on the fair value of the investments.

Headquarter Facility Exit Obligation

Changes in the Company’s facility exit obligation related to its former headquarters lease during the nine months ended September 29, 2013 are as follows (in thousands):



	Headquarter Facility Exit Obligation
Balance as of December 30, 2012	$	45,352
Adjustment to facility exit obligation	(1,948		)
Accretion of interest expense	1,716
Cash settlements	(7,974		)
Balance as of September 29, 2013	$	37,146

Facility exit obligation liability recorded upon vacating the Company’s former headquarters was adjusted for updates to assumptions based on terms of the facility sublease agreements entered during the nine months ended September 29, 2013.

Warranties

Changes in the Company’s reserve for product warranties during the nine months ended September 29, 2013 are as follows (in thousands):



	Warranty Reserve
Balance as of December 30, 2012	$	10,136
Additions charged to cost of revenue	13,929
Repairs and replacements	(12,748		)
Balance as of September 29, 2013	$	11,317

Inventory

Inventory consists of the following (in thousands):



	September 29, 2013		December 30, 2012
Raw materials	$	59,714	$	61,665
Work in process	74,146		75,675
Finished goods	26,006		21,378
Total inventory	$	159,866	$	158,718

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):



	September 29, 2013		December 30, 2012
Accrued compensation expenses	$	68,273	$	59,864
Deferred revenue, current portion	48,158		55,817
Accrued taxes payable	24,882		23,021
Customer deposits	14,676		13,765
Reserve for product warranties	11,317		10,136
Acquisition related contingent liability, current portion	6,426		9,490
Facility exit obligation, current portion	6,154		8,063
Accrued royalties	2,841		2,836
Unsettled short-term investment purchase	—		9,154
Other	17,250		9,731
Total accrued liabilities	$	199,977	$	201,877