Balance Sheet Information (Tables)

9 Months Ended

Sep. 30, 2012

Balance Sheet Information

Schedule of available-for-sale securities

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

	September 30, 2012
	Amortized Cost		Gains in Accumulated Other Comprehensive Income		Losses in Accumulated Other Comprehensive Income			Estimated Fair Value
Treasury bills	$	117,872	$	54	$	—		$	117,926
Government Agency Securities	39,559		4		(1		)	39,562
FDIC guaranteed corporate debt	28,198		6		—			28,204
Total available-for-sale securities	$	185,629	$	64	$	(1	)	$	185,692

	December 31, 2011
	Amortized Cost		Gains in Accumulated Other Comprehensive Income		Losses in Accumulated Other Comprehensive Income			Estimated Fair Value
Treasury bills	$	70,147	$	46	$	(1	)	$	70,192
Government agency securities	88,585		62		(6		)	88,641
FDIC guaranteed corporate debt	114,640		125		(7		)	114,758
Total available-for-sale securities	$	273,372	$	233	$	(14	)	$	273,591

Summary of fair value of short-term investments that have been in an unrealized loss position for less than 12 months

The tables below show the fair value of short-term investments that have been in an unrealized loss position for less than 12 months (in thousands):

	September 30, 2012
	Less than 12 months					Total
	Fair value		Gross Unrealized Losses			Fair value		Gross Unrealized Losses
Government agency securities	$	18,519	$	(1	)	$	18,519	$	(1	)
Total	$	18,519	$	(1	)	$	18,519	$	(1	)

	December 31, 2011
	Less than 12 months					Total
	Fair value		Gross Unrealized Losses			Fair value		Gross Unrealized Losses
Government agency securities	$	20,497	$	(6	)	$	20,497	$	(6	)
FDIC guaranteed corporate debt	8,033		(7		)	8,033		(7		)
Treasury bills	5,024		(1		)	5,024		(1		)
Total	$	33,554	$	(14	)	$	33,554	$	(14	)

Schedule of contractual maturities of available-for-sale debt securities

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

	Estimated Fair Value
Due in one year or less	$	107,269
Due in 1–2 years	78,423
Total investments in debt securities	$	185,692

Schedule of inventories

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

	September 30,		December 31,
	2012		2011
Materials	$	44,475	$	57,169
Work in process	23,780		20,118
Finished goods	6,105		36,147
	$	74,360	$	113,434

Schedule of changes in warranty liability

Changes in our warranty liability during the period are as follows (in thousands):

	September 30,
	2012			2011
Balance as of the beginning of period	$	8,731		$	8,266
Warranties issued during the period	2,486			5,988
Settlements made during the period	(6,389		)	(6,523		)
Changes in estimate during the period	1,418			1,259
Balance as of the end of period	$	6,246		$	8,990