FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2012

FAIR VALUE MEASUREMENTS

Schedule of fair value measurements of financial assets and liabilities

The fair value measurements of our financial assets and liabilities are identified at the following levels within the fair value hierarchy (in thousands):

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
At September 30, 2012
Financial assets carried at fair value:
Money market funds	$	—	$	1,041		—	$	1,041
Commercial paper		—		26,747		—		26,747
Corporate notes		—		7,921		—		7,921
U.S. government and U.S government agency notes		—		89,245		—		89,245
Equity securities		31		—		—		31
Total	$	31	$	124,954		—	$	124,985
Financial liabilities carried at fair value:
Deferred acquisition consideration		—		—	$	16,911	$	16,911
Warrant liability		—		—		316		316
Total		—		—	$	17,227	$	17,227
At December 31, 2011
Financial assets carried at fair value:
Money market funds	$	—	$	4,469		—	$	4,469
Commercial paper		—		31,394		—		31,394
Corporate notes		—		1,435		—		1,435
U.S. government and U.S government agency notes		—		72,913		—		72,913
Equity securities		1,819		—		—		1,819
Total	$	1,819	$	110,211		—	$	112,030
Financial liabilities carried at fair value:
Deferred acquisition consideration		—		—	$	28,977	$	28,977
Warrant liability		—		—		187		187
Total		—		—	$	29,164	$	29,164

Schedule of reconciliations of financial liabilities measured at fair value using significant unobservable inputs

The following table provides reconciliations of financial liabilities measured at fair value using significant unobservable inputs (Level 3)(in thousands):

	Deferred Acquisition Consideration			Warrant Liability
Balances at December 31, 2011	$	28,977		$	187
Installments payment of deferred consideration		(12,272	)		—
Change in fair value		206			129
Balances at September 30, 2012	$	16,911		$	316

Schedule of fair value of warrants estimated using Black-Scholes option-pricing model based on assumptions

	Fair Value
	September 30, 2012			December 31, 2011
Risk-free interest rate		1.21	%		1.32	%
Dividend yield		—			—
Expected volatility		63.48	%		69.18	%
Expected life (in years)		5.00			5.75