Marketable Securities

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

During the year ended December 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.

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 consolidated balance sheet. In March 2018, we sold all common stock we held for total proceeds of $23.9 million and recognized a loss of $5.0 million in interest and other income, net during the year ended December 31, 2018.

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



	December 31,
	2018							2017
	Amortized Cost		Unrealized Loss			Estimated Fair Value		Cost or Amortized Cost		Unrealized Gain, Net		Estimated Fair Value
Marketable securities	$	249,944	$	(342	)	$	249,602	$	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 December 31, 2018.