Cash and Cash Equivalents

6 Months Ended

Jun. 30, 2018

The carrying values of the Company's cash and cash equivalents are as follows:



	As of June 30,		As of December 31,
	2018		2017
	(in thousands)
	(unaudited)
Cash	$	103,690	$	70,459
Cash equivalents	41,769		193,315
Restricted cash - letters of credit	3,827		3,872
Total cash and cash equivalents	$	149,286	$	267,646

The carrying value of the Company's cash equivalents approximates fair value. See "Note 4 — Fair Value of Financial Instruments".

Letters of credit are secured by cash held on deposit.