Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2018

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):

	June 30, 2018
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds	$	153,241	$	—	$	—	$	153,241
U.S. government agencies	—		74,897		—		74,897
Corporate debt securities	—		217,806		—		217,806
Derivative assets	—		5,464		—		5,464
Total	$	153,241	$	298,167	$	—	$	451,408
Liabilities:
Derivative liabilities	$	—	$	736	$	—	$	736
Stock warrant liability	—		—		486		486
Total	$	—	$	736	$	486	$	1,222

	December 31, 2017
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds	$	193,066	$	—	$	—	$	193,066
U.S. government agencies	—		79,624		—		79,624
Corporate debt securities	—		291,582		—		291,582
Total	$	193,066	$	371,206	$	—	$	564,272
Liabilities:
Derivative liabilities	$	—	$	2,138	$	—	$	2,138
Stock warrant liability	—		—		208		208
Total	$	—	$	2,138	$	208	$	2,346