FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured and Carried at Fair Value

The tables below present information about the Company’s financial assets and liabilities that are measured and carried at fair value and indicate the level within the fair value hierarchy of the valuation techniques it utilizes to determine such fair value:

	Fair Value Measurement as of March 31, 2014
	Total		Level 1		Level 2		Level 3
	(in thousands)
Cash equivalents	$	8,162	$	912	$	7,250	$	—
Commercial paper		24,890		—		24,890
Government and government agency bonds		88,745		—		88,745		—
Corporate bonds		62,456		—		62,456		—
Certificates of deposit		7,897		7,897		—		—
Total assets	$	192,150	$	8,809	$	183,341	$	—

	Fair Value Measurement as of December 31, 2013
	Total		Level 1		Level 2		Level 3
	(in thousands)
Cash equivalents	$	185,000	$	185,000	$	—	$	—
Certificates of deposit		7,897		7,897		—		—
Total assets	$	192,897	$	192,897	$	—	$	—

	Fair Value Measurement as of March 31, 2014
	Total		Level 1		Level 2		Level 3
	(in thousands)
Warrants	$	9,213	$	—	$	—	$	9,213
Total liabilities	$	9,213	$	—	$	—	$	9,213

	Fair Value Measurement as of December 31, 2013
	Total		Level 1		Level 2		Level 3
	(in thousands)
Warrants	$	9,006	$	—	$	—	$	9,006
Total liabilities	$	9,006	$	—	$	—	$	9,006