Components of Deferred Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred tax liabilities:
Intangibles	$ 2,385	$ 2,813
Deferred tax assets:
Net operating loss carryforwards	161,951	134,065
Federal and state tax credit carryovers	23,380	24,489
Depreciation	4,924	4,837
Stock-based compensation	3,420	3,122
Other	2,158	1,289
Total deferred tax assets	195,833	167,802
Deferred tax assets, net	193,448	164,989
Valuation allowance	(193,448)	(164,989)
Total deferred taxes