FAIR VALUE MEASUREMENTS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Included in cash and cash equivalents
Amortized Cost	$ 5,542	$ 18,796
Gross Unrealized Losses		(1)
Estimated Fair Value	5,542	18,795
Restricted cash
Amortized Cost	795	794
Estimated Fair Value	795	794
Marketable securities
Amortized Cost	61,979	73,431
Gross Unrealized Gains	17	48
Gross Unrealized Losses	(30)	(7)
Estimated Fair Value	61,966	73,472
Money market funds
Included in cash and cash equivalents
Amortized Cost	5,542	15,660
Estimated Fair Value	5,542	15,660
Certificates of deposit
Restricted cash
Amortized Cost	795	794
Estimated Fair Value	795	794
Government-sponsored enterprise securities
Marketable securities
Amortized Cost	6,440	8,618
Gross Unrealized Gains	1	5
Estimated Fair Value	6,441	8,623
Commercial paper
Marketable securities
Amortized Cost	20,236	20,623
Gross Unrealized Gains	11	21
Estimated Fair Value	20,247	20,644
Corporate notes
Included in cash and cash equivalents
Amortized Cost		3,136
Gross Unrealized Losses		(1)
Estimated Fair Value		3,135
Marketable securities
Amortized Cost	35,303	44,190
Gross Unrealized Gains	5	22
Gross Unrealized Losses	(30)	(7)
Estimated Fair Value	$ 35,278	$ 44,205

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Amount of gross unrealized gains from available-for-sale securities as of the reporting date.

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Amount of gross unrealized losses from available-for-sale securities as of the reporting date.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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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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Amount of 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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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 short-term 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. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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The aggregate value of all restricted investments.

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