Net Operating Loss and Tax Credit Carryovers (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Internal Revenue Service (IRS)
Income Tax [Line Items]
Net operating loss	$ 35,399
Net operating loss, Expiration Year	2032
State and Local Jurisdiction
Income Tax [Line Items]
Net operating loss	95,780
Net operating loss, Expiration Year	2017-2027
Minimum Tax Credits
Income Tax [Line Items]
Net operating loss	22,314
Net operating loss, Expiration Year	Indefinite
General Business Tax Credit Carryforward
Income Tax [Line Items]
Net operating loss	$ 406
Net operating loss, Expiration Year	2027-2028