Cash, Cash Equivalents and Short-Term Investments (Tables)

3 Months Ended

Mar. 31, 2019

Cash and Cash Equivalents [Abstract]

Schedule of Cash, Cash Equivalents and Short-Term Investments

The amortized cost, unrealized gains and losses and estimated fair value of the Company's cash, cash equivalents and short-term investments as of March 31, 2019 and December 31, 2018 consisted of the following:



	As of March 31, 2019
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value

Cash	$	109.8	$	—	$	—		$	109.8
Cash equivalents:
Money market funds	226.9		—		—			226.9
Commercial paper	19.5		—		—			19.5
Corporate notes and obligations	3.0		—		—			3.0
Total cash and cash equivalents	$	359.2	$	—	$	—		$	359.2
Investments
Corporate notes and obligations	244.7		0.6		—			245.3
U.S. Treasury securities	193.0		—		(0.1		)	192.9
Certificates of deposit	52.2		—		—			52.2
U.S. agency obligations	38.5		—		—			38.5
Commercial Paper	27.1		—		—			27.1
Total short-term investments	555.5		0.6		(0.1		)	556.0
Total	$	914.7	$	0.6	$	(0.1	)	$	915.2



	As of December 31, 2018
	Amortized cost		Unrealized gain		Unrealized loss			Estimated fair value

Cash	$	103.0	$	—	$	—		$	103.0
Cash equivalents
Money market funds	355.5		—		—			355.5
U.S. Treasury securities	33.4		—		—			$	33.4
Commercial paper	27.4		—		—			27.4
Total cash and cash equivalents	$	519.3	$	—	$	—		$	519.3
Short-term investments
Corporate notes and obligations	269.6		0.1		(0.5		)	269.2
U.S. Treasury securities	176.0		—		(0.1		)	175.9
Certificates of deposit	70.6		—		—			70.6
U.S. agency obligations	37.1		—		—			37.1
Commercial paper	17.2		—		—			17.2
Total short-term investments	570.5		0.1		(0.6		)	570.0
Total	$	1,089.8	$	0.1	$	(0.6	)	$	1,089.3

Contractual Maturities of Short Term Investments

The following table presents the contractual maturities of the Company’s short-term investments as of March 31, 2019:



	As of March 31, 2019
	Amortized cost		Estimated fair value

Due within one year	$	337.9	$	338.1
Due between one to three years	217.6		217.9
Total	$	555.5	$	556.0