Income Tax Expense (benefit) Differed from Amounts Computed by Applying Statutory Federal Income Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Income tax provision at statutory rate	$ (6,021)	$ (3,717)	$ (4,341)
Nondeductible items	349	25	13
Change in tax credits	39	(202)	(251)
Change in valuation allowance	5,894	3,963	4,443
Other	(261)	(69)	136
Income Tax Expense (Benefit), Total

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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-Publisher FASB

-Name Accounting Standards Codification

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-Number 210

-Section 08

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-Name Accounting Standards Codification

-Glossary Income Tax Expense (or Benefit)

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-Name Accounting Standards Codification

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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The amount of the change in the period in the valuation allowance for a specified deferred tax asset.

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-Name Accounting Standards Codification

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