Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current Deferred Tax Assets:
U.S. federal and state net operating loss carryforwards	$ 36,028,000	$ 6,020,000
Accruals, reserves and other	20,322,000	21,950,000
Valuation allowance	(4,937,000)	(3,622,000)
Current deferred tax assets, net	51,413,000	24,348,000
Noncurrent Deferred Tax Assets (Liabilities):
U.S. federal and state net operating loss carryforwards	8,448,000	28,394,000
Capitalized research and development costs	25,374,000	23,214,000
Tax credit and capital loss carryforwards	14,885,000	18,695,000
Intangible assets and other	2,159,000	517,000
Debt costs	(4,710,000)	(6,835,000)
Excess tax depreciation and other	(38,969,000)	(7,008,000)
Noncurrent deferred tax assets, gross	7,187,000	56,977,000
Valuation allowance	(4,456,000)	(9,171,000)
Noncurrent deferred tax assets, net	2,731,000	47,806,000
Total deferred tax assets, net	54,144,000	72,154,000
Current:
Federal	384,000	960,000	1,127,000
State	841,000	816,000	1,901,000
Foreign	115,000	0	0
Total current	1,340,000	1,776,000	3,028,000
Deferred:
Federal	29,558,000	21,247,000	16,407,000
State	(10,259,000)	(5,408,000)	(7,820,000)
Total deferred	19,299,000	15,839,000	8,587,000
Total income tax provision	20,639,000	17,615,000	11,615,000
Effective income tax rate reconciliation [Abstract]
U.S. federal statutory rate (in hundredths)	35.00%	35.00%	35.00%
State taxes (in hundredths)	3.30%	3.40%	3.40%
Extraterritorial income exclusion (in hundredths)	(8.70%)	0.00%	0.00%
Research and development credits (in hundredths)	(4.50%)	(11.40%)	(17.10%)
Other, net (in hundredths)	(1.70%)	0.10%	2.20%
Changes in valuation allowance, net (in hundredths)	0.00%	0.00%	0.60%
Effective rate (in hundredths)	23.40%	27.10%	24.10%
Reconciliation of unrecognized tax benefits [Roll Forward]
Unrecognized tax benefits at beginning of year	12,386,000	7,508,000	2,891,000
Additions based on tax positions related to the current year	2,325,000	4,372,000	3,430,000
Additions for tax positions of prior years	2,351,000	562,000	1,187,000
Settlements with taxing authorities and other	0	(56,000)	0
Reduction resulting from lapse of statute of limitation	(330,000)	0	0
Unrecognized tax benefits at end of year	16,732,000	12,386,000	7,508,000
Extraterritorial income exclusion	7,700,000
Income before income taxes from foreign income	400,000
U.S. Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	128,900,000
Expiration of net operating loss carryforwards	beginning 2022 through 2030
Capital Loss Carryforwards [Line Items]
Capital loss carryforwards	$ 800,000
Expiration of capital loss carryforwards	2015