Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Financial Instruments Measured at Fair Value on Recurring Basis

The following table sets 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):

Balance as of December 31, 2017	Level 1		Level 2		Level 3		Total
Assets:
Money market funds (i)	$	30,278	$	—	$	—	$	30,278
Commercial paper (ii)		—		61,086		—		61,086
Corporate notes (ii)		—		165,381		—		165,381
Total assets	$	30,278	$	226,467	$	—	$	256,745

Balance as of December 31, 2016	Level 1		Level 2		Level 3		Total
Assets:
Money market funds (i)	$	35,510	$	—	$	—	$	35,510
Commercial paper (ii)		—		160,582		—		160,582
Corporate notes (ii)		—		74,369		—		74,369
Total assets	$	35,510	$	234,951	$	—	$	270,461

(i) Included in cash and cash equivalents on the consolidated balance sheets.

(ii) Included in short-term investments on the consolidated balance sheets