SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Available-for-sale Investments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 83,238
Gross Unrealized Gains	291
Gross Unrealized Losses	0
Estimated Fair Market Value	83,529
Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	23,111
Gross Unrealized Gains	32
Gross Unrealized Losses	0
Estimated Fair Market Value	23,143
Investments due in 4-12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	29,694
Gross Unrealized Gains	142
Gross Unrealized Losses	0
Estimated Fair Market Value	29,836
Investments due in more than 12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	30,433
Gross Unrealized Gains	117
Gross Unrealized Losses	0
Estimated Fair Market Value	30,550
Commercial paper [Member] \| Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	16,672
Gross Unrealized Gains	2
Gross Unrealized Losses	0
Estimated Fair Market Value	16,674
Corporate securities [Member] \| Investments due in less than 3 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	6,439
Gross Unrealized Gains	30
Gross Unrealized Losses	0
Estimated Fair Market Value	6,469
Corporate securities [Member] \| Investments due in 4-12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	19,694
Gross Unrealized Gains	141
Gross Unrealized Losses	0
Estimated Fair Market Value	19,835
Corporate securities [Member] \| Investments due in more than 12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	30,433
Gross Unrealized Gains	117
Gross Unrealized Losses	0
Estimated Fair Market Value	30,550
Certificates of Deposit [Member] \| Investments due in 4-12 months [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	10,000
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Estimated Fair Market Value	$ 10,001

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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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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