Other Balance Sheet Amounts

The Company holds restricted cash as collateral for credit cards. At March 31, 2016 and December 31, 2015, restricted cash included in prepaid expenses and other current assets was $0.3 million, respectively.

Investments in marketable securities as of March 31, 2016 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

	(in thousands)
Available-for-sale - short-term:
U.S. Treasury, government and agency debt securities	$	15,449	$	2	$	(1	)	$	15,450
Corporate debt securities	6,397		—		—			6,397
Total	$	21,846	$	2	$	(1	)	$	21,847
Available-for-sale - long-term:
U.S. Treasury, government and agency debt securities	$	8,539	$	—	$	(5	)	$	8,534

As of March 31, 2016, the Company's available-for-sale securities had a weighted remaining contractual maturity of 0.7 years. For the three months ended March 31, 2016 the gross realized gains and gross realized losses were not significant and there were no unrealized holding gains (losses) reclassified out of accumulated other comprehensive income (loss) into the consolidated statements of operations for the sale of available-for-sale investments.

Investments in marketable securities as of December 31, 2015 consisted of the following:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

	(in thousands)
Available-for-sale - short-term:
U.S. Treasury, government and agency debt securities	$	10,485	$	—	$	(22	)	$	10,463
Corporate debt securities	12,786		—		—			12,786
Total	$	23,271	$	—	$	(22	)	$	23,249
Available-for-sale - long-term:
U.S. Treasury, government and agency debt securities	$	13,529	$	—	$	(46	)	$	13,483

The amortized cost and fair value of the Company's marketable securities at March 31, 2016, by contractual years-to-maturity are as follows:



	Amortized Cost		Fair Value

	(in thousands)
Due in less than 1 year	$	21,846	$	21,847
Due within 1-2 years	8,539		8,534
Total	$	30,385	$	30,381

Accounts payable and accrued expenses included the following:



	March 31, 2016		December 31, 2015

	(in thousands)
Accounts payable—seller	$	166,085	$	228,850
Accounts payable—trade	8,492		6,962
Accrued employee-related payables	10,822		12,155
Total	$	185,399	$	247,967

At March 31, 2016 and December 31, 2015, accounts payable—seller are recorded net of $0.7 million, respectively, due from sellers for services provided by the Company to sellers, where the Company has the right of offset.