Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments Debt And Equity Securities [Abstract]

Summary of Available for Sale Securities Held

The following table summarizes the available-for-sale securities held at December 31, 2016 and 2015 (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2016
Description:
U.S. government agency securities and treasuries	$	79,411	$	—	$	(9	)	$	79,402
Total	$	79,411	$	—	$	(9	)	$	79,402

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2015
Description:
U.S. government agency securities and treasuries	$	114,724	$	—	$	(178	)	$	114,546
Total	$	114,724	$	—	$	(178	)	$	114,546

Estimated Market Value of Marketable Securities by Maturity

The estimated market value of marketable securities by maturity date is as follows (in thousands):

	December 31,2016		December 31,2015
Due in one year or less	$	79,402	$	89,607
Due after one year through two years		—		24,939
Total	$	79,402	$	114,546