Balance Sheet Information

6 Months Ended

Jun. 30, 2012

Balance Sheet Information

Balance Sheet Information

Note 4—Balance Sheet Information

Short-term Investments

Available-for-sale securities consist of the following (in thousands):

	June 30, 2012
	Amortized  Cost		Gains in  Accumulated  Other  Comprehensive  Income		Losses in  Accumulated  Other  Comprehensive  Income			Estimated  Fair Value
Government Agency Securities	$	43,742	$	23	$	—		$	43,765
FDIC insured corporate bonds	60,958		4		—			60,962
Treasury bills	117,106		—		(1		)	117,105
Total available-for-sale securities	$	221,806	$	27	$	(1	)	$	221,832

	December 31, 2011
	Amortized  Cost		Gains in  Accumulated  Other  Comprehensive  Income		Losses in  Accumulated  Other  Comprehensive  Income		Estimated  Fair Value
Government Agency Securities	$	88,585	$	119	$	—	$	88,704
FDIC insured corporate bonds	114,640		56		—		114,696
Treasury bills	70,147		44		—		70,191
Total available-for-sale securities	$	273,372	$	219	$	—	$	273,591

During the three and six months ended June 30, 2012, available-for-sale securities were sold for total proceeds of $55.9 million and $99.5 million, respectively. The gross realized gains and losses on these sales were minimal for the three and six months ended June 30, 2012. For purpose of determining gross realized gains and losses, the cost of securities sold is based on specific identification. Net unrealized holding losses on available-for-sale securities of $0.1 million and $0.2 million for the three and six months ended June 30, 2012, respectively, have been included in accumulated other comprehensive income. During the three and six months ended June 30, 2011, available-for-sale securities were sold for total proceeds of $252.0 million and $374.2 million, respectively. The gross realized gains on these sales were $0.2 million for the three and six months ended June 30, 2011. Net unrealized holding gains on available-for-sale securities amounting to $0.2 million for the three and six months ended June 30, 2011, have been included in accumulated other comprehensive income.

Contractual maturities of available-for-sale debt securities at June 30, 2012, are as follows (in thousands):

	Estimated Fair Value
Due in one year or less	$	30,751
Due in 1—2 years	191,081
Total investments in debt securities	$	221,832

Actual maturities may differ from contractual maturities because some borrowers have the right to call or prepay obligations with or without call or prepayment penalties.

Restricted Cash

As of June 30, 2012 and December 31, 2011, restricted cash consisted of $0.9 million and $0.6 million, respectively, which serves as collateral for bank guarantees that provide financial assurance that the Company will fulfill certain customer obligations. This cash is held in custody by the issuing bank, and is restricted as to withdrawal or use while the related bank guarantees are outstanding.

Accounts Receivable, net

Accounts receivable are shown net of the allowance for doubtful accounts of $0.5 million as of June 30, 2012 and December 31, 2011.

Inventories

Inventories are stated at the lower of cost (principally first-in, first-out) or market. Inventories consist of (in thousands):

	June 30,		December 31,
	2012		2011
Raw materials	$	54,992	$	57,169
Work in process	22,049		20,118
Finished goods	13,688		36,147
	$	90,729	$	113,434

Accrued Warranty

We estimate the costs that may be incurred under the warranty we provide and record a liability in the amount of such costs at the time the related revenue is recognized. Factors that affect our warranty liability include product failure rates, material usage and labor costs incurred in correcting product failures during the warranty period. We periodically assess the adequacy of our recognized warranty liability and adjust the amount as necessary. Changes in our warranty liability during the period are as follows (in thousands):

	June 30,
	2012			2011
Balance as of the beginning of period	$	9,778		$	9,238
Warranties issued during the period	1,502			5,843
Settlements made during the period	(3,821		)	(4,489		)
Balance as of the end of period	$	7,459		$	10,592