Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Summary of Available-for-sale Investments

The following tables summarize the Company’s available-for-sale investments at December 31, 2017 and 2016 (in thousands):

AVAILABLE-FOR-SALE INVESTMENTS
December 31, 2017
(in thousands)
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposit	$	13,441	$	—	$	—		$	13,441
US Treasury securities	14,787		—		(71		)	14,716
US 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

AVAILABLE-FOR-SALE INVESTMENTS
December 31, 2016
(in thousands)
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposit	$	7,257	$	—	$	—		$	7,257
US Treasury securities	8,553		1		(10		)	8,544
US Agency securities	4,514		—		(13		)	4,501
Asset-backed securities	5,554		3		—			5,557
Corporate notes and bonds	32,717		3		(60		)	32,660
Total	$	58,595	$	7	$	(83	)	$	58,519

Summary of Maturities of Available-for-sale Investments

The following table summarizes the maturities of the Company’s available-for-sale securities at December 31, 2017, and 2016 (in thousands):

AVAILABLE-FOR-SALE INVESTMENT MATURITIES
(in thousands)
	At December 31, 2017				At December 31, 2016
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than 1 year	$	55,801	$	55,735	$	45,391	$	45,344
Due in 1-5 years	25,040		24,913		13,204		13,175
Total	$	80,841	$	80,648	$	58,595	$	58,519