Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Summary of Assets and Liabilities Carried at Fair Value

A summary of the assets and liabilities carried at fair value in accordance with the hierarchy defined above is as follows (in thousands):

	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
September 30, 2018 (unaudited)
Assets:
Money market funds	$	9,850	$	—	$	—	$	9,850
Corporate notes		—		31,694		—		31,694
Commercial paper		—		83,744		—		83,744
Asset backed securities		—		12,198		—		12,198
Government notes		—		12,430		—		12,430
Total assets	$	9,850	$	140,066		—	$	149,916

	Fair Value Measurements Using
	Level 1		Level 2		Level 3		Total
December 31, 2017:
Assets:
Money market funds	$	8,685	$	—	$	—	$	8,685
Corporate notes		5,103		40,995		—		46,098
Government notes		6,175		—		—		6,175
Total assets	$	19,963	$	40,995	$	—	$	60,958