3.	CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS

The following is a summary of cash equivalents and short-term investments by type of instrument at March 31, 2013 and December 31, 2012 (in thousands):

	March 31, 2013
	Amortized		Gross Unrealized					Fair
	Cost		Gains		Losses			Value
Money market funds	$	6,524	$	—	$	—		$	6,524
Commercial paper		11,186		—		—			11,186
U.S. agency securities		57,509		16		—			57,525
Corporate bonds		30,987		—		(14	)		30,973
Total investments	$	106,206	$	16	$	(14	)	$	106,208

Reported as:
Cash equivalents	$	6,524	$	—	$	—		$	6,524
Short-term investments		99,682		16		(14	)		99,684
Total investments	$	106,206	$	16	$	(14	)	$	106,208

	December 31, 2012
	Amortized		Gross Unrealized					Fair
	Cost		Gains		Losses			Value
Money market funds	$	13,505	$	-	$	-		$	13,505
Commercial paper		9,696		-		-			9,696
U.S. agency securities		51,276		18		-			51,294
Corporate bonds		34,751		5		(5	)		34,751
U.S. Government bonds		5,019		2		-			5,021
Total investments	$	114,247	$	25	$	(5	)	$	114,267

Reported as:
Cash equivalents	$	13,505	$	-	$	-		$	13,505
Short-term investments		100,742		25		(5	)		100,762
Total	$	114,247	$	25	$	(5	)	$	114,267

As of March 31, 2013, all investments were classified as available-for-sale with unrealized gains and losses recorded as a separate component of accumulated other comprehensive income (loss). Cash equivalents consist of highly liquid investments with remaining maturities of three months or less at the date of purchase. Short-term investments have a remaining maturity of greater than three months at the date of purchase and an effective maturity of less than one year. None of the Company's short-term investments have been at a continuous unrealized loss position for greater than 12 months.

The Company reviews its investments for impairment quarterly. For investments with an unrealized loss, the factors considered in the review include the credit quality of the issuer, the duration that the fair value has been less than the adjusted cost basis, severity of impairment, reason for the decline in value and potential recovery period, the financial condition and near-term prospects of the investees, and whether the Company would be required to sell an investment due to liquidity or contractual reasons before its anticipated recovery. Based on its review, the Company did not identify any investments that were other-than-temporarily impaired during the three months ended March 31, 2013.

The Company did not incur any material realized gains or losses in the three months ended March 31, 2013 and 2012. The cost of securities sold was determined based on the specific identification method.