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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Sum of investments and unrestricted cash as of the balance sheet date.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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Fair Value Measurements - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash and cash equivalents
Cash	$ 27,186,000us-gaap_Cash	$ 28,436,000us-gaap_Cash
Restricted Cash and Cash Equivalents	525,000	0
Money market funds	62,244,000us-gaap_MoneyMarketFundsAtCarryingValue	62,261,000us-gaap_MoneyMarketFundsAtCarryingValue
Total cash and cash equivalents	89,955,000	90,697,000	77,407,000	77,376,000
Long-term restricted cash	2,600,000us-gaap_LongTermInvestments	2,599,000us-gaap_LongTermInvestments
Total cash and cash equivalents and investments	92,555,000us-gaap_InvestmentsAndCash	93,296,000us-gaap_InvestmentsAndCash
Fair Value, Inputs, Level 1
Cash and cash equivalents
Long-term restricted cash	2,600,000
Cash and cash equivalents	$ 90,000,000