3. CASH, CASH EQUIVALENTS AND INVESTMENTS

Securities classified as cash and cash equivalents and short-term investments as of December 31, 2016 and December 31, 2015 are summarized below (in thousands). Estimated fair value is based on quoted market prices for these investments.


	December 31, 2016
	Amortized Cost		Gross Unrealized					Fair Value
	Amortized Cost		Gains		Losses			Fair Value
Cash and cash equivalents:
Cash	$	3,638	$	—	$	—		$	3,638
Money market funds		68,561		—		—			68,561
Commercial paper		2,399		—		—			2,399

Total cash and cash equivalents	$	74,598	$	—	$	—		$	74,598
Short-term investments
Corporate bonds		58,464		2		(56	)	$	58,410
Commercial paper		62,946		5		(20	)		62,931
Asset-backed securities		4,886		—		(2	)		4,884
Total short-term investments	$	126,296	$	7	$	(78	)	$	126,225

Total	$	200,894	$	7	$	(78	)	$	200,823


	December 31, 2015
	Amortized Cost		Gross Unrealized					Fair Value
	Amortized Cost		Gains		Losses			Fair Value
Cash and cash equivalents:
Cash	$	25,194	$	—	$	—		$	25,194
Money market funds		81,810		—		—			81,810

Total cash and cash equivalents	$	107,004	$	—	$	—		$	107,004

During the three months ended December 31, 2016, the Company determined that one of its bank accounts comprising $24.0 million at December 31, 2015 should have been classified as cash rather than as money market funds. Accordingly, the impact of this reclassification has been reflected in the table for December 31, 2015 presented above. The Company made a similar reclassification in NOTE 4, FAIR VALUE MEASUREMENTS. This change in classification does not affect previously reported financial statements for any period.

Cash equivalents consist of money market funds and corporate debt securities with original maturities of three months or less at the time of purchase, and the carrying amount is a reasonable approximation of fair value. The Company invests its cash in high quality securities of financial and commercial institutions. These securities are carried at fair value, which is based on readily available market information, with unrealized gains and losses included in “accumulated other comprehensive loss” within stockholders’ equity on the Company’s consolidated balance sheets. The Company uses the specific identification method to determine the amount of realized gains or losses on sales of marketable securities. For the year ended December 31, 2016, there were no realized gains or losses on the available-for-sale securities.

All available-for-sale securities held as of December 31, 2016 had contractual maturities of less than one year. Investments that have maturities beyond one year as of the end of the reporting period are classified as non-current. The Company’s available-for-sale securities are subject to a periodic impairment review. The Company considers a debt security to be impaired when its fair value is less than its carrying cost, in which case the Company would further review the investment to determine whether it is other-than-temporarily impaired. When the Company evaluates an investment for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and any changes thereto, intent to sell, and whether it is more likely than not the Company will be required to sell the investment before the recovery of its cost basis. If an investment is other-than-temporarily impaired, the Company writes it down through the statement of operations to its fair value and establishes that value as a new cost basis for the investment. The Company did not identify any of its available-for-sale securities as other-than-temporarily impaired in any of the periods presented. As of December 31, 2016, no investment was in a continuous unrealized loss position for more than one year, the unrealized losses were not due to a change in credit risk and the Company believes that is more likely than not the investments will be held until maturity or a forecasted recovery of fair value.