Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Summary of Financial Assets, and Liabilities, Allocated into Level 1, Level 2, and Level 3 Measured on Recurring Basis

The following table sets forth the fair value of our financial assets and liabilities, allocated into Level 1, Level 2 and Level 3, that was measured on a recurring basis (in thousands):

	December 31, 2013
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	57,296	$	-	$	-	$	57,296
Corporate notes and commercial paper		-		182,472		-		182,472
U.S. government agency securities		-		75,289		-		75,289
Foreign currency forward contracts				372				372
Total financial assets	$	57,296	$	258,133	$	-	$	315,429
	December 31, 2012
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	43,303	$	-	$	-	$	43,303
Corporate notes and commercial paper		-		64,425		-		64,425
U.S. government agency securities		-		19,346		-		19,346
Foreign currency forward contracts		-		51		-		51
Total financial assets	$	43,303	$	83,822	$	-	$	127,125
Financial Liabilities:
Convertible preferred stock warrant liability	$	-	$	-	$	683	$	683

Summary of Changes in Estimated Fair Value

Level 3 liabilities include the convertible preferred stock warrant liability (see Note 10). The following table sets forth a summary of the changes in the estimated fair value of our convertible preferred stock warrants, which were measured at fair value on a recurring basis (in thousands):

Balance as of December 31, 2010	$	789
Recognized gain		(23	)
Balance as of December 31, 2011		766
Recognized gain		(83	)
Balance as of December 31, 2012		683
Recognized gain		(24	)
Balance as of December 31, 2013	$	-