SHORT-TERM INVESTMENTS

6 Months Ended

Jun. 30, 2015

SHORT-TERM INVESTMENTS

SHORT-TERM INVESTMENTS

4. SHORT-TERM INVESTMENTS (in thousands)

        As of June 30, 2015, short-term investments consisted of the following:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available-for-sale securities:
Corporate notes and bonds	$	430,855	$	6	$	(1,591	)	$	429,270
U.S. agency obligations		68,343		7		(61	)		68,289
U.S. treasury securities		55,434		7		(5	)		55,436
Commercial paper		39,259		—		(17	)		39,242
Certificates of deposit		10,320		3		(1	)		10,322
Total available-for-sale securities	$	604,211	$	23	$	(1,675	)	$	602,559

        As of December 31, 2014, the Company held no short-term investments.

        The following table summarizes the estimated fair value of our short-term investments, designated as available-for-sale and classified by the contractual maturity date of the securities as of the dates shown:

	June 30, 2015		December 31, 2014
Due in one year or less	$	144,711	$	—
Due in greater than one year		457,848		—
Total	$	602,559	$	—

        The Company has certain available-for-sale securities in a gross unrealized loss position, all of which have been in such position for less than 12 months. The Company reviews its debt securities classified as short-term investments on a regular basis to evaluate whether or not any security has experienced an other-than-temporary decline in fair value. The Company considers factors such as the length of time and extent to which the market value has been less than the cost, the financial position and near-term prospects of the issuer and the Company's intent to sell, or whether it is more likely than not the Company will be required to sell the investment before recovery of the investment's amortized-cost basis. If the Company determines that an other-than-temporary decline exists in one of these securities, the unrealized losses attributable to the respective investment would be reclassified to realized loss within the statement of income. For debt securities, the portion of the write-down related to credit loss would be recognized to other income, net in our consolidated statements of income. Any portion not related to credit loss would be included in accumulated other comprehensive income. There were no impairments considered other-than-temporary as of June 30, 2015.

        The following table shows the fair values and the gross unrealized losses of available-for-sale securities that have been in a gross unrealized loss position for less than 12 months, aggregated by investment category as of June 30, 2015:

	Estimated Fair Value		Gross Unrealized Losses
Corporate notes and bonds	$	409,095	$	(1,591	)
U.S. agency obligations		52,770		(61	)
U.S. treasury securities		26,506		(5	)
Commercial paper		39,242		(17	)
Certificates of deposit		2,639		(1	)
	$	530,252	$	(1,675	)