Short-term Investments

12 Months Ended

Dec. 31, 2014

Short-term Investments

(5) Short-term Investments

The Company periodically invests a portion of its excess cash in short-term investment instruments. Substantially all of the Company’s short-term investments are in U.S. Treasury securities, and the Company has the ability and intent to hold these investments to maturity. The stated maturity dates of these investments are between three months and one year from the purchase date. These held-to-maturity investments are recorded at amortized cost and included within “Short-term investments” on the accompanying Consolidated Balance Sheets. The fair value of held-to-maturity investments in U.S. Treasury securities is determined based on quoted market prices in active markets for identical securities (Level 1 inputs).

The amortized cost, carrying value, and fair value of held-to-maturity investments at December 31, 2014 were $198.5 million, $198.5 million, and $198.5 million, respectively. The amortized cost, carrying value, and fair value of held-to-maturity investments at December 31, 2013 were $137.2 million, $137.2 million, and $137.2 million, respectively. The gross unrecognized holding gains and losses were not material for 2014, 2013, or 2012. No other-than-temporary impairments related to these investments have been recognized in accumulated other comprehensive loss as of December 31, 2014 and December 31, 2013. As of December 31, 2014 and December 31, 2013, the Company’s available-for-sale investments were not material.