Cash Equivalents and Investments (Tables)

9 Months Ended

Sep. 30, 2018

Investments Debt And Equity Securities [Abstract]

Summary of Available-for-sale Securities

The following table summarizes the available‑for‑sale securities (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
September 30, 2018 (unaudited)
Money market funds	$	9,850	$	—	$	—		$	9,850
Corporate notes		31,749		—		(55	)		31,694
Commercial paper		83,744		—		—			83,744
Asset backed securities		12,226		—		(28	)		12,198
Government notes		12,448		—		(18	)		12,430
Total	$	150,017	$	—	$	(101	)	$	149,916

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2017:
Money market funds	$	8,685	$	—	$	—		$	8,685
Corporate notes		46,133		—		(35	)		46,098
Government notes		6,191		—		(16	)		6,175
Total	$	61,009	$	—	$	(51	)	$	60,958