4. Cash, Cash Equivalents, Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2015

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Schedule of Cash, Cash Equivalents and Marketable Securities

Cash, cash equivalents, and marketable securities consisted of the following at March 31, 2015 and December 31, 2014 (in thousands):

	March 31, 2015		December 31, 2014
Cash and cash equivalents:
Cash	$	722,413	$	1,480,452
Cash equivalents:
Money market funds	57,495		1,602
Total cash and cash equivalents	779,908		1,482,054
Marketable securities:
Foreign debt	663,174		462,731
Time deposits	40,000		40,000
U.S. debt	—		2,800
U.S. government obligations	1,500		3,501
Total marketable securities	704,674		509,032
Total cash, cash equivalents, and marketable securities	$	1,484,582	$	1,991,086

Available-for-sale Securities

The following tables summarize the unrealized gains and losses related to our available-for-sale marketable securities, by major security type, as of March 31, 2015 and December 31, 2014 (in thousands):

	As of March 31, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Foreign debt	$	663,753	$	200	$	779	$	663,174
Time deposits	40,000		—		—		40,000
U.S. government obligations	1,500		—		—		1,500
Total	$	705,253	$	200	$	779	$	704,674

	As of December 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Foreign debt	$	463,466	$	18	$	753	$	462,731
Time deposits	40,000		—		—		40,000
U.S. debt	2,800		—		—		2,800
U.S. government obligations	3,500		1		—		3,501
Total	$	509,766	$	19	$	753	$	509,032

Available-for-sale Securities by Maturity

The contractual maturities of our marketable securities as of March 31, 2015 and December 31, 2014 were as follows (in thousands):

	As of March 31, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
One year or less	$	227,154	$	8	$	170	$	226,992
One year to two years	254,830		65		250		254,645
Two years to three years	223,269		127		359		223,037
Total	$	705,253	$	200	$	779	$	704,674

	As of December 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
One year or less	$	329,974	$	14	$	174	$	329,814
One year to two years	125,892		5		380		125,517
Two years to three years	53,900		—		199		53,701
Total	$	509,766	$	19	$	753	$	509,032

Available-for-sale Securities Continuous Unrealized Loss Position

The following tables show gross unrealized losses and estimated fair values for those marketable securities that were in an unrealized loss position as of March 31, 2015 and December 31, 2014, aggregated by major security type and the length of time the marketable securities have been in a continuous loss position (in thousands):

	As of March 31, 2015
	In Loss Position for Less Than 12 Months				In Loss Position for 12 Months or Greater				Total
	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
Foreign debt	$	421,117	$	779	$	—	$	—	$	421,117	$	779
Total	$	421,117	$	779	$	—	$	—	$	421,117	$	779

	As of December 31, 2014
	In Loss Position for Less Than 12 Months				In Loss Position for 12 Months or Greater				Total
	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
Foreign debt	$	391,840	$	740	$	41,060	$	13	$	432,900	$	753
Total	$	391,840	$	740	$	41,060	$	13	$	432,900	$	753