Cash, cash equivalents and short-term investments

Cash and cash equivalents consist of highly liquid fixed-income investments with original maturities of three months or less at the time of purchase, including money market funds. Short-term investments consist of readily marketable securities with a remaining maturity of more than three months from the date of purchase. We classify all of our cash equivalents and short-term investments as “available for sale,” as these investments are free of trading restrictions. These marketable securities are carried at fair value, with the unrealized gains and losses, net of tax, reported as accumulated other comprehensive income and included as a separate component of stockholders’ equity. Gains and losses are recognized when realized. When we have determined that an other-than-temporary decline in fair value has occurred, the amount of the decline that is related to a credit loss is recognized in earnings. Gains and losses are determined using the specific identification method. We had no material realized gains or losses in the three and six months ended December 31, 2012 and 2011.

Cash, cash equivalents and short-term investments consisted of the following as of December 31, 2012 (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash	$	21,174	$	—	$	—		$	21,174
Cash equivalents:
Money market mutual funds	1,576		—		—			1,576
Total cash equivalents	1,576		—		—			1,576
Total cash and cash equivalents	22,750		—		—			22,750
Short-term securities:
Certificates of deposit	1,000		3		—			1,003
Municipal securities	165,975		234		(37		)	166,172
Commercial paper	4,989		7		—			4,996
Corporate bonds	12,778		109		—			12,887
Total short-term investments	184,742		353		(37		)	185,058
Cash, cash equivalents and short-term investments	$	207,492	$	353	$	(37	)	$	207,808

Cash, cash equivalents and short-term investments consisted of the following as of June 30, 2012 (in thousands):



	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash	$	1,430	$	—	$	—		$	1,430
Cash equivalents:
Money market mutual funds	4,490		—		—			4,490
Commercial paper	1,000							1,000
Total cash equivalents	5,490		—		—			5,490
Total cash and cash equivalents	6,920		—		—			6,920
Short-term investments:
Asset-backed securities	1,001		—		(1		)	1,000
Certificates of deposit	2,750		—		—			2,750
Municipal securities	160,114		208		(81		)	160,241
Commercial paper	3,463		2		—			3,465
Corporate bonds	25,045		57		(10		)	25,092
Total short-term investments	192,373		267		(92		)	192,548
Cash, cash equivalents and short-term investments	$	199,293	$	267	$	(92	)	$	199,468

The following table summarizes the cost and estimated fair value of short-term fixed income securities classified as short-term investments based on stated maturities as of December 31, 2012 (in thousands):



	Amortized Cost		Estimated Fair Value
Due within one year	$	55,482	$	55,561
Due within two years	112,483		112,668
Due after two years	16,777		16,829
Total	$	184,742	$	185,058

Declines in fair value judged to be other-than-temporary on securities available for sale are included as a component of other income, net. In order to determine whether a decline in value is other-than-temporary, we evaluate, among other factors: the duration and extent to which the fair value has been less than the carrying value and our intent and ability to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair market value. As of December 31, 2012, we did not consider any of our investments to be other-than-temporarily impaired.