Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Line Items]

Schedule Of Deferred Revenue And Customer Advances

	2011		2010
	(in thousands)
Customer advances	$	70,001	$	132,559
Maintenance, training and extended warranty		33,953		36,626
Undelivered elements		7,939		5,858
Acceptance		318		2,083
Total deferred revenue and customer advances	$	112,211	$	177,126

Schedule Of Product Warranty

	Amount
	(in thousands)
Balance at December 31, 2008	$	7,552
Accruals for warranties issued during the period		7,950
Accruals related to pre-existing warranties		(769	)
Settlements made during the period		(8,298	)
Balance at December 31, 2009		6,435
Accruals for warranties issued during the period		17,084
Accruals related to pre-existing warranties		(1,338	)
Settlements made during the period		(12,295	)
Balance at December 31, 2010		9,886
Acquisition		327
Accruals for warranties issued during the period		13,167
Accruals related to pre-existing warranties		(2,689	)
Settlements made during the period		(12,538	)
Balance at December 31, 2011	$	8,153

Schedule Of Extended Product Warranty

	Amount
	(in thousands)
Balance at December 31, 2008	$	6,604
Deferral of new extended warranty revenue		2,552
Recognition of extended warranty deferred revenue		(4,694	)
Balance at December 31, 2009		4,462
Deferral of new extended warranty revenue		7,696
Recognition of extended warranty deferred revenue		(3,186	)
Balance at December 31, 2010		8,972
Acquisition		3,151
Deferral of new extended warranty revenue		8,659
Recognition of extended warranty deferred revenue		(8,040	)
Balance at December 31, 2011	$	12,742

Schedule Of Property, Plant And Equipment

Buildings	40 years
Building improvements	5 to 10 years
Leasehold improvements	Lesser of lease term or useful life
Furniture and fixtures	10 years
Test systems manufactured internally	6 years
Machinery and equipment	3 to 5 years
Software	3 to 5 years

Schedule Of Stock Compensation Plan Activity

	2011		2010		2009
	(in thousands)
Cost of revenue	$	7,097	$	6,536	$	4,138
Engineering and development		10,001		9,209		7,648
Selling and administrative		15,239		14,032		12,568
Stock-based compensation		32,337		29,777		24,354
Income tax benefit		—		—		(1,049	)
Total stock-based compensation expense after income taxes	$	32,337	$	29,777	$	23,305

Stock Options [Member]

Accounting Policies [Line Items]

Schedule Of Fair Value Of Stock Options Estimated Using Weighted Average Assumptions

	2011			2010			2009
Expected life (years)		4.00			4.75			4.75
Interest rate		1.5	%		2.4	%		1.6	%
Volatility-historical		52.1	%		48.8	%		44.9	%
Dividend yield		0.0	%		0.0	%		0.0	%

Stock Purchase Rights [Member]

Accounting Policies [Line Items]

Schedule Of Fair Value Of Stock Options Estimated Using Weighted Average Assumptions

	2011			2010			2009
Expected life (years)		0.5			0.5			0.5
Interest rate		0.1	%		0.2	%		0.3	%
Volatility-historical		41.0	%		48.0	%		73.6	%
Dividend yield		0.0	%		0.0	%		0.0	%