Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2012

Fair Value of Financial Instruments [Abstract]

Financial assets and liabilities measured at fair value on a recurring basis

The following table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2012 and December 31, 2011:

	September 30, 2012		Quoted Price in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents – money market fund	$	230,069	$	230,069	$	—	$	—

	December 31, 2011		Quoted Price in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents – money market fund	$	59,860	$	59,860	$	—	$	—

Valuation of preferred stock

The change in the valuation of preferred stock warrants for the nine months ended September 30, 2011 is summarized below.

	Nine Months Ended September 30,
	2011
Fair value, beginning of year	$	12
Change in fair value		183
Fair value, end of period	$	195