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 December 31, 2018 consisted of the following:



	Amortized cost		Unrealized gain		Unrealized loss			Estimated fair value

Cash	$	103.0	$	—	$	—		103.0
Cash equivalents
Money market funds	355.5		—		—			355.5
Commercial paper	27.4		—		—			27.4
U.S. Treasury securities	33.4		—		—			33.4
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

The Company's cash and cash equivalents at December 31, 2017 consisted of cash of $62.9 million and money market funds of $367.1 million. The Company did not have short-term investments as of December 31, 2017.

Included in cash and cash equivalents is cash in transit from payment processors for credit and debit card transactions of $11.9 million and $13.3 million as of December 31, 2018 and December 31, 2017, respectively.

All short-term investments were designated as available-for-sale securities as of December 31, 2018.

The following table presents the contractual maturities of the Company’s short-term investments as of December 31, 2018:



	Amortized cost		Estimated fair value

Due within one year	$	327.6	$	327.5
Due between one to three years	242.9		242.5
Total	$	570.5	$	570.0

As of December 31, 2018, the following short-term investments were in unrealized loss positions:



	Less than 12 months					12 months or greater				Total
	Fair value		Unrealized losses			Fair value		Unrealized losses		Fair value		Unrealized losses
Corporate notes and obligations	$	209.5	$	(0.5	)	$	—	$	—	$	209.5	$	(0.5	)
U.S. Treasury securities	127.8		(0.1		)	—		—		127.8		(0.1		)
Total	$	337.3	$	(0.6	)	$	—	$	—	$	337.3	$	(0.6	)

The Company had 202 short-term investments in unrealized loss positions as of December 31, 2018. There were no material gross unrealized losses from available-for-sale securities and no material realized gains or losses from available-for-sale securities that were reclassified out of accumulated other comprehensive income for the year ended December 31, 2018.

For investments in available-for-sale debt securities that have unrealized losses, the Company evaluates whether (i) it has the intention to sell any of these investments and (ii) whether it is not more likely than not that it will be required to sell any of these investments before recovery of the entire amortized cost basis. Based on this evaluation, the Company determined that there were no other-than-temporary impairments associated with short-term investments as of December 31, 2018.

The Company recorded $16.8 million, $3.0 million, and $0.9 million in interest income from its cash, cash equivalents and short-term investments for the years ended December 31, 2018, 2017 and 2016, respectively.