Cash, Cash Equivalents and Available for Sale Securities

The Company considers all highly liquid investments purchased with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents included cash of $241.5 million and $114.1 million at September 30, 2011 and December 31, 2010, respectively. Cash and cash equivalents at September 30, 2011 and December 31, 2010 also included investments of $16.5 million and $12.2 million, respectively, in money market funds and commercial paper with original maturities of less than three months.

At September 30, 2011 and December 31, 2010, the Company held available for sale securities with a fair value totaling $49.7 million and $120.3 million, respectively. These available for sale securities included various U.S. government agency notes, U.S. treasury notes and corporate debt securities. At September 30, 2011, all of the $49.7 million of available for sale securities were due within one year. At December 31, 2010, approximately $115.2 million of available for sale securities were due within one year. The remaining $5.1 million were due within two years.

Available for sale securities, including carrying value and estimated fair values, are summarized as follows:



	As of September 30, 2011									As of December 31, 2010
	Cost		Fair Value		Carrying Value		Unrealized Gain			Cost		Fair Value		Carrying Value		Unrealized Gain
	(in thousands)
U.S. government agency notes	$	14,917	$	14,919	$	14,919	$	2		$	55,222	$	55,222	$	55,222	$	—
U.S. treasury notes	3,054		3,056		3,056		2			—		—		—		—
Corporate debt securities	31,765		31,764		31,764		(1		)	65,055		65,058		65,058		3
Total	$	49,736	$	49,739	$	49,739	$	3		$	120,277	$	120,280	$	120,280	$	3

Restricted Cash

The Company had restricted cash of $4.6 million and $5.8 million at September 30, 2011 and December 31, 2010, respectively, which is included in restricted cash on the consolidated balance sheets. On October 11, 2007, the Company entered into a lease for new office space in Parsippany, New Jersey. The Company relocated its principal executive offices to the new space in the first quarter of 2009. Restricted cash of $4.1 million and $5.5 million at September 30, 2011 and December 31, 2010, respectively, collateralized outstanding letters of credit associated with this lease. The funds are invested in certificates of deposit. The letter of credit permits draws by the landlord to cure defaults by the Company. The amount of the letter of credit is subject to reduction upon the achievement of certain regulatory and operational milestones relating to the Company's products. However, in no event will the amount of the letter of credit be reduced below approximately $1.0 million. In addition, as a result of the acquisition of Targanta in 2009, the Company had at September 30, 2011 and December 31, 2010 restricted cash of $0.2 million and $0.3 million, respectively, in the form of a guaranteed investment certificate collateralizing an available credit facility. The Company also had at September 30, 2011 restricted cash of $0.3 million related to certain foreign tender requirements.