FAIR VALUE MEASUREMENTS (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Assets:
Marketable securities	$ 0		$ 11,577
Recurring basis
Assets:
Money market funds	135,314		306,604
Marketable securities			11,577
Cash equivalents	135,314		306,604
Total financial assets	135,314		318,181
Liabilities:
Acquisition-related contingent consideration	(381,037)		(455,082)
Available-for-sale equity securities
Assets:
Marketable securities	0		4,410
Available-for-sale equity securities | Recurring basis
Assets:
Marketable securities	0		4,410
Auction rate floating securities
Assets:
Marketable securities	0		7,167
Auction rate floating securities | Recurring basis
Assets:
Marketable securities	0		7,167
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring basis
Assets:
Money market funds	135,314		306,604
Marketable securities	0	[1]	4,410
Cash equivalents	135,314		306,604
Total financial assets	135,314		311,014
Liabilities:
Acquisition-related contingent consideration	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Available-for-sale equity securities | Recurring basis
Assets:
Marketable securities	0		4,410
Quoted Prices in Active Markets for Identical Assets (Level 1) | Auction rate floating securities | Recurring basis
Assets:
Marketable securities	0		0
Significant Other Observable Inputs (Level 2) | Recurring basis
Assets:
Money market funds	0		0
Marketable securities	0		0
Cash equivalents	0		0
Total financial assets	0		0
Liabilities:
Acquisition-related contingent consideration	0		0
Significant Other Observable Inputs (Level 2) | Available-for-sale equity securities | Recurring basis
Assets:
Marketable securities	0		0
Significant Other Observable Inputs (Level 2) | Auction rate floating securities | Recurring basis
Assets:
Marketable securities	0		0
Significant Unobservable Inputs (Level 3) | Recurring basis
Assets:
Money market funds	0		0
Marketable securities	0		7,167
Cash equivalents	0		0
Total financial assets	0		7,167
Liabilities:
Acquisition-related contingent consideration	(381,037)		(455,082)
Significant Unobservable Inputs (Level 3) | Available-for-sale equity securities | Recurring basis
Assets:
Marketable securities	0		0
Significant Unobservable Inputs (Level 3) | Auction rate floating securities | Recurring basis
Assets:
Marketable securities	$ 0		$ 7,167

[1] Marketable securities are classified within Prepaid expenses and other current assets and Other long-term assets, net in the consolidated balance sheets.