Investments (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-Sale Investments

The following tables summarize the Company’s available-for-sale investments at September 30, 2018 and December 31, 2017 (in thousands):

	September 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposit	$	12,481	$	—	$	—		$	12,481
U.S. Treasury securities	34,390		—		(122		)	34,268
U.S. Agency securities	8,017		—		(66		)	7,951
Commercial paper	18,456		—		—			18,456
Asset-backed securities	11,968		—		(1		)	11,967
Corporate notes and bonds	33,916		2		(59		)	33,859
Total	$	119,228	$	2	$	(248	)	$	118,982

	December 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposit	$	13,441	$	—	$	—		$	13,441
U.S. Treasury securities	14,787		—		(71		)	14,716
U.S. Agency securities	8,510		—		(51		)	8,459
Commercial paper	9,171		—		—			9,171
Asset-backed securities	3,026		—		(1		)	3,025
Corporate notes and bonds	31,906		—		(70		)	31,836
Total	$	80,841	$	—	$	(193	)	$	80,648

Schedule of Available-For-Sale Investment Maturities

The following table summarizes the maturities of the Company’s available-for-sale securities at September 30, 2018 and December 31, 2017 (in thousands):

	September 30, 2018				December 31, 2017
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than 1 year	$	93,971	$	93,825	$	55,801	$	55,735
Due in 1-3 years	25,257		25,157		25,040		24,913
Total	$	119,228	$	118,982	$	80,841	$	80,648