4. Cash and cash equivalents and marketable securities

Cash and cash equivalents and marketable securities consisted of the following:


	March 31,		December 31,
	2019		2018
Cash and cash equivalents:
Cash	$	4,611	$	11,689
Money market accounts		59,910		137,723
Marketable securities		4,495		—
Total cash and cash equivalents	$	69,016	$	149,412
Short-term marketable securities-available-for-sale:
Marketable securities	$	36,888	$	—
Total short-term marketable securities	$	36,888	$	—

All contractual maturities of marketable securities were less than one year at March 31, 2019. Marketable securities consist primarily of debt securities which include commercial paper and debt instruments including notes issued by foreign or domestic industrial and financial corporations and governments which pay in U.S. dollars and carry a rating of A or better. For the three months ended March 31, 2019 and 2018, interest income was $714 and $8, respectively, which is included in interest and other expense, net in the accompanying condensed consolidated statements of operations.