Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2017

Investments Debt And Equity Securities [Abstract]

Summary of Available for Sale Securities Held

The following table summarizes the available-for-sale securities held at September 30, 2017 and December 31, 2016 (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
September 30, 2017
Description:
U.S. government agency securities and treasuries	$	—	$	—	$	—		$	—
Total	$	—	$	—	$	—		$	—
December 31, 2016
Description:
U.S. government agency securities and treasuries	$	79,411	$	—	$	(9	)	$	79,402
Total	$	79,411	$	—	$	(9	)	$	79,402

Estimated Market Value of Marketable Securities by Maturity

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

	September 30, 2017		December 31, 2016
Due in one year or less	$	—	$	79,402
Due after one year through two years		—		—
Total	$	—	$	79,402