Fair Value Hierarchy for Financial Assets Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 9,237	[1]	$ 9,237	[1]
Assets, Fair Value Disclosure, Total	9,237		9,237
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	9,237	[1]	9,237	[1]
Assets, Fair Value Disclosure, Total	$ 9,237		$ 9,237

[1] Included in "Cash and cash equivalents" in the consolidated balance sheets as of March 31, 2012 and December 31, 2011 in addition to $21.6 million and $20.6 million, respectively, of cash. Unrealized gains and losses on money market funds were nominal due to the short-term nature of the investments.