Investments

Certificates of Deposit – We held $4.8 million and $5.2 million in certificates of deposit at June 30, 2013, and December 31, 2012, respectively. At June 30, 2013, the certificates of deposit bear interest ranging from 0.25% to 0.85% per annum and have various maturities ranging from approximately five months to two years.

Investments Held to Maturity – Our investments held to maturity are comprised of $18.8 million of corporate notes and bonds with original maturities ranging from less than one month to 22 months. The investments have moderate risk with S&P ratings ranging from A+ to BBB-.

We record the amortized cost basis and accrued interest of the corporate notes and bonds in the Consolidated Balance Sheets. We record the interest and amortization of bond premium to interest income in the Consolidated Statements of Income.

The following summarizes the amortized cost and estimated fair value of our investments held to maturity as of June 30, 2013 and December 31, 2012:



	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)			Fair Value
June 30, 2013:	(in thousands)
Current assets:
Investments held to maturity	$	7,353	$	3	$	—		$	7,356
Non current assets:
Investments held to maturity	11,475		—		(59		)	11,416
Total	$	18,828	$	3	$	(59	)	$	18,772
December 31, 2012:
Current assets:
Investments held to maturity	$	2,832	$	—	$	(1	)	$	2,831
Non current assets:
Investments held to maturity	8,041		—		(9		)	8,032
Total	$	10,873	$	—	$	(10	)	$	10,863