Cash, Cash Equivalents and Available-for-sale Securities	3 Months Ended
Mar. 31, 2015
Cash, Cash Equivalents and Available-for-sale Securities
Cash, Cash Equivalents and Available-for-sale Securities	5. Cash, Cash Equivalents and Available-for-sale Securities All highly liquid investments with maturities of three months or less at the date of purchase are classified as cash equivalents. As of March 31, 2015 and December 31, 2014, the amount of cash and cash equivalents was $78.7 million and $146.5 million, respectively and consists of checking accounts and short-term money market mutual funds held at U.S. commercial banks. The Company’s available-for-sale securities as of March 31, 2015 and December 31, 2014 consist of approximately $99.9 million and $49.9 million, respectively in U.S. Treasury securities with maturities of less than one year and have been classified and accounted for as available-for-sale. Management determines the appropriate classification of its investments at the time of purchase and reevaluates the available-for-sale designations as of each balance sheet date. As of March 31, 2015, there were no unrealized losses on available-for-sale securities. The Company recognized no net realized gains or losses for the three months ended March 31, 2015. The Company considers the declines in market value of its marketable securities investment portfolio to be temporary in nature. Fair values were determined for each individual security in the investment portfolio and marked to market. When evaluating the investments for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and any changes thereto, and the Company’s intent to sell, or whether it is more likely than not it will be required to sell, the investment before recovery of the investment’s amortized cost basis. During the three months ended March 31, 2015 and 2014, the Company did not recognize any impairment charges. As of March 31, 2015 and December 31, 2014, the Company did not consider any of its investments to be other-than-temporarily impaired.

5. Cash, Cash Equivalents and Available-for-sale Securities

All highly liquid investments with maturities of three months or less at the date of purchase are classified as cash equivalents. As of March 31, 2015 and December 31, 2014, the amount of cash and cash equivalents was $78.7 million and $146.5 million, respectively and consists of checking accounts and short-term money market mutual funds held at U.S. commercial banks.

The Company’s available-for-sale securities as of March 31, 2015 and December 31, 2014 consist of approximately $99.9 million and $49.9 million, respectively in U.S. Treasury securities with maturities of less than one year and have been classified and accounted for as available-for-sale. Management determines the appropriate classification of its investments at the time of purchase and reevaluates the available-for-sale designations as of each balance sheet date. As of March 31, 2015, there were no unrealized losses on available-for-sale securities. The Company recognized no net realized gains or losses for the three months ended March 31, 2015. The Company considers the declines in market value of its marketable securities investment portfolio to be temporary in nature. Fair values were determined for each individual security in the investment portfolio and marked to market. When evaluating the investments for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and any changes thereto, and the Company’s intent to sell, or whether it is more likely than not it will be required to sell, the investment before recovery of the investment’s amortized cost basis. During the three months ended March 31, 2015 and 2014, the Company did not recognize any impairment charges. As of March 31, 2015 and December 31, 2014, the Company did not consider any of its investments to be other-than-temporarily impaired.