The Company invests in available-for-sale debt securities consisting of money market funds, certificates of deposit, U.S. Treasury securities and U.S. government sponsored enterprise securities. Available-for-sale debt securities are classified as part of either cash and cash equivalents or short-term investments in the condensed balance sheets. Available-for-sale debt securities with maturities of three months or less from the date of purchase have been classified as cash equivalents, and were $10.6 million and $17.2 million as of March 31, 2019 and December 31, 2018 respectively. Available-for-sale debt securities with maturities of more than three months from the date of purchase have been classified as short-term investments, and were as follows (in thousands):

	Amortized Cost		Unrealized Gain		Unrealized Loss			Market Value
March 31, 2019:
U.S. Treasury securities	$	70,654	$	23	$	(6	)	$	70,671
	$	70,654	$	23	$	(6	)	$	70,671
December 31, 2018:
U.S. Treasury securities	$	63,674	$	1	$	(24	)	$	63,651
	$	63,674	$	1	$	(24	)	$	63,651

As of March 31, 2019, the Company had 12 securities in a gross unrealized loss position, all which have been in such position for less than twelve months. At each reporting date, the Company performs an evaluation of impairment to determine if the unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, and the Company’s intent and ability to hold the investment until recovery of its amortized cost basis. Otonomy intends and has the ability, to hold its investments in unrealized loss positions until their amortized cost basis has been recovered. The Company determined there were no other-than-temporary declines in the value of any available-for-sale securities as of March 31, 2019. All the Company’s available-for-sale debt securities mature within one year.

The Company obtains the fair value of its available-for-sale debt securities from a professional pricing service. The fair values of available-for-sale debt securities are validated by comparing the fair values reported by the professional pricing service to quoted market prices or to fair values obtained from the custodian bank.