Cash Equivalents and Investments (Tables)

9 Months Ended

Sep. 30, 2018

Investments Debt And Equity Securities [Abstract]

Amortized Cost and Fair Value of Cash Equivalents and Available for Sale Investments

The amortized cost and fair value of cash equivalents and available for sale investments at September 30, 2018 and December 31, 2017 were as follows (in thousands):

	September 30, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	26,353	$	—	$	—		$	26,353
U.S. Treasury securities		79,489		-		(97	)		79,392
Agency bonds		27,675		—		(9	)		27,666
Commercial paper		62,872		-		(16	)		62,856
Corporate obligations		13,883		—		(4	)		13,879
	$	210,272	$	-	$	(126	)	$	210,146

	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents	$	111,501	$	—	$	—		$	111,501
Short-term investments	$	143,895	$	—	$	(210	)	$	143,685
Long-term investments	$	16,538	$	—	$	(20	)	$	16,518