Marketable Securities

3 Months Ended

Mar. 31, 2018

Investments, Debt and Equity Securities [Abstract]

During the quarter ended March 31, 2018, our marketable securities consisted of United States Treasury notes and common stock. The United States Treasury notes are classified as available-for-sale and mature in 2019. Available-for-sale securities are presented on our condensed consolidated balance sheets at fair value. Changes in values of the United States Treasury notes are recognized in accumulated other comprehensive loss.

On January 1, 2018 we adopted ASU 2016-01 (see Note 2) and reclassified a $1.9 million unrealized gain from cumulative other comprehensive loss to cumulative net income on our condensed consolidated balance sheet. Changes in values of common stock are recognized in interest and other income, net on the condensed consolidated statements of operations. In March 2018, we sold all common stock we held and recognized a loss of $5.0 million in interest and other income, net during the three months ended March 31, 2018.

Below is a summary of our marketable securities as of March 31, 2018 and December 31, 2017 (in thousands):



	March 31, 2018							December 31, 2017
	Amortized Cost		Unrealized Loss			Estimated Fair Value		Cost or Amortized Cost		Unrealized Gain, Net		Estimated Fair Value
Marketable securities	$	249,646	$	(1,767	)	$	247,879	$	276,567	$	361	$	276,928

The unrealized losses on our United States Treasury notes were caused by interest rate increases. The contractual terms of those investments do not permit the issuer to settle the securities at a price less than the amortized cost bases of the investments. Because we do not intend to sell the investments and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases, which may be maturity, we do not consider those investments to be other-than-temporarily impaired at March 31, 2018.