Marketable Securities

3 Months Ended

Mar. 31, 2018

Investments, Debt and Equity Securities [Abstract]

3	Marketable Securities

The Company’s marketable securities within cash equivalents and investments included in the consolidated balance sheets are detailed as follows (in thousands):


	March 31, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
U.S. Treasury securities	$	426,999	$	1	$	(1,968	)	$	425,032
Foreign government securities		6,987		—		(40	)		6,947
Corporate debt securities		1,297,659		328		(5,109	)		1,292,878
Time deposits		301,279		—		(2	)		301,277
Equity securities		77		70		—			147

Total	$	2,033,001	$	399	$	(7,119	)	$	2,026,281

Amounts included in:
Cash equivalents	$	190,931	$	1	$	(2	)	$	190,930
Investments		1,842,070		398		(7,117	)		1,835,351

Total	$	2,033,001	$	399	$	(7,119	)	$	2,026,281


	December 31, 2017
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
U.S. Treasury securities	$	593,599	$	82	$	(1,693	)	$	591,988
Foreign government securities		6,982		—		(30	)		6,952
Corporate debt securities		1,977,329		897		(3,066	)		1,975,160
Time deposits		371,515		—		(4	)		371,511
Equity securities		77		70		—			147

Total	$	2,949,502	$	1,049	$	(4,793	)	$	2,945,758

Amounts included in:
Cash equivalents	$	194,377	$	—	$	(1	)	$	194,376
Investments		2,755,125		1,049		(4,792	)		2,751,382

Total	$	2,949,502	$	1,049	$	(4,793	)	$	2,945,758

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


	March 31, 2018		December 31, 2017
Due in one year or less	$	1,226,896	$	1,722,553
Due after one year through three years		497,961		851,547

Total	$	1,724,857	$	2,574,100