Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value of Financial Assets and Liabilities Measured on Recurring Basis

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

	June 30, 2018
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	27,208	$	—	$	—	$	27,208
Corporate notes and commercial paper	—			247,081		—		247,081
U.S. Treasury bills and government agency securities		—		163,121		—		163,121
Total financial assets	$	27,208	$	410,202	$	—	$	437,410
Financial Liabilities:
Embedded derivatives liabilities	$	—	$	—	$	7,286	$	7,286

	December 31, 2017
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	31,836	$	—	$	—	$	31,836
Corporate notes and commercial paper		—		313,164		—		313,164
U.S. Treasury bills and government agency securities		—		170,458		—		170,458
Total financial assets	$	31,836	$	483,622	$	—	$	515,458
Financial Liabilities:
Embedded derivatives liabilities	$	—	$	—	$	8,854	$	8,854

Summary of Changes in Estimated Fair Value of Embedded Derivative Liabilities Measured on Recurring Basis

The following table sets forth a summary of the changes in the estimated fair value of our embedded derivative liabilities, which were measured at fair value on a recurring basis (in thousands):

Balance as of December 31, 2017	$	8,854
Net decrease in fair value included in interest and other income (expense), net		(1,568	)
Balance as of June 30, 2018	$	7,286