Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of fair value of assets and liabilities measured on recurring basis

The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	September 30, 2017
	Level 1		Level 2		Total
Assets:
Money market funds	$	129,790	$	—	$	129,790
U.S. government agencies	—		50,707		50,707
Corporate debt securities	—		375,891		375,891
Derivative assets	—		1,307		1,307
Total	$	129,790	$	427,905	$	557,695
Liabilities:
Derivative liabilities	$	—	$	11,826	$	11,826

	December 31, 2016
	Level 1		Level 2		Total
Assets:
Money market funds	$	50,125	$	—	$	50,125
U.S. government agencies	—		86,526		86,526
Corporate debt securities	—		390,286		390,286
Derivative assets	—		10,625		10,625
Total	$	50,125	$	487,437	$	537,562
Liabilities:
Derivative liabilities	$	—	$	3,780	$	3,780