Cash and Investments (Tables)

6 Months Ended

Jun. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-Sale Securities

The following tables summarize cash and cash equivalents, investments, and restricted cash and investments by balance sheet line item as of June 30, 2017 and December 31, 2016 (in thousands):



	June 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and cash equivalents	$	135,212	$	—	$	—		$	135,212
Short-term investments	214,172		15		(143		)	214,044
Long-term investments	26,404		26		(17		)	26,413
Long-term restricted cash and investments	4,650		—		—			4,650
Total cash and investments	$	380,438	$	41	$	(160	)	$	380,319



	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and cash equivalents	$	151,686	$	—	$	—		$	151,686
Short-term investments	268,234		13		(130		)	268,117
Long-term investments	55,792		1		(192		)	55,601
Long-term restricted cash and investments	4,150		—		—			4,150
Total cash and investments	$	479,862	$	14	$	(322	)	$	479,554

Summary of Cash Equivalents and Investments by Security Type

The following tables summarize our cash equivalents and investments by security type as of June 30, 2017 and December 31, 2016. The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):



	June 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Money market funds	$	48,253	$	—	$	—		$	48,253
Commercial paper	303,877		41		(132		)	303,786
Corporate bonds	550		—		—			550
U.S. Treasury and government sponsored enterprises	15,664		—		(28		)	15,636
Total investments	$	368,344	$	41	$	(160	)	$	368,225



	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Money market funds	$	71,457	$	—	$	—		$	71,457
Commercial paper	165,375		—		—			165,375
Corporate bonds	152,712		3		(308		)	152,407
U.S. Treasury and government sponsored enterprises	70,730		11		(14		)	70,727
Total investments	$	460,274	$	14	$	(322	)	$	459,966

Summary of Available-for-Sale Securities by Contractual Maturity

The following table summarizes the fair value of securities classified as available-for-sale by contractual maturity as of June 30, 2017 (in thousands):



	Mature within One Year		After One Year through Two Years		Fair Value
Money market funds	$	48,253	$	—	$	48,253
Commercial paper	281,572		22,214		303,786
Corporate bonds	—		550		550
U.S. Treasury and government sponsored enterprises	13,986		1,650		15,636
Total investments	$	343,811	$	24,414	$	368,225