Marketable Securities and Fair Value Measurements | Marketable Securities and Fair Value Measurements Marketable Securities As of June 30, 2016 and December 31, 2015 , all of the Company’s marketable securities were classified as available-for-sale and their estimated fair values were $98.2 million and $96.8 million , respectively. We periodically review our available-for-sale securities for other-than-temporary impairment. We consider factors such as the duration, severity and the reason for the decline in value, the potential recovery period, and our intent to sell. As of June 30, 2016 , the Company’s available-for-sale securities primarily consisted of corporate bonds and other government obligations that are priced at fair value. During the three and six months ended June 30, 2016 and 2015 , we did not recognize any other-than-temporary impairment loss. The maturities of the Company’s long-term marketable securities generally range from one to three years. The following tables present details of the Company’s marketable securities as of June 30, 2016 and December 31, 2015 (in thousands): June 30, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Short-term: Investment securities $ 44,780 $ 51 $ (3 ) $ 44,828 Commercial paper 2,883 1 — 2,884 Long-term: Investment securities 50,250 284 (7 ) 50,527 Total $ 97,913 $ 336 $ (10 ) $ 98,239 December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Short-term: Investment securities $ 16,908 $ — $ (13 ) $ 16,895 Long-term: Investment securities 80,172 2 (291 ) 79,883 Total $ 97,080 $ 2 $ (304 ) $ 96,778 Fair Value Measurements The Company's financial assets and liabilities are measured at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The three levels of inputs used to measure fair value are as follows: ▪ Level 1—Unadjusted quoted prices in active markets for identical assets or liabilities ▪ Level 2—Unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable or can be corroborated by observable market data for substantially the full-term of the asset or liability ▪ Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the asset or liability This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The Company measures its cash equivalents and short-term and long-term investments at fair value. The Company classifies its cash equivalents and restricted cash within Level 1 because the Company values these investments using quoted market prices. The fair value of the Company's Level 1 financial assets is based on quoted market prices of the identical underlying security. The Company classifies short-term and long-term investments within Level 2 because unadjusted quoted prices for identical or similar assets in markets are not active. The Company does not have any assets or liabilities classified as Level 3 financial assets. The following tables set forth the fair value of the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2016 and December 31, 2015 based on the three-tier value hierarchy (in thousands): June 30, 2016 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 130,644 $ — $ — $ 130,644 Commercial paper — 2,884 — 2,884 Short-term investments: Certificates of deposit 35,000 — — 35,000 Investment securities — 44,828 — 44,828 Restricted cash: Certificate of deposit 5,000 — — 5,000 Long-term: Investment securities — 50,527 — 50,527 Total $ 170,644 $ 98,239 $ — $ 268,883 December 31, 2015 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 267,300 $ — $ — $ 267,300 Short-term investments: Certificates of deposit 35,000 — — 35,000 Investment securities — 16,895 — 16,895 Restricted cash: Certificate of deposit 5,000 — — 5,000 Long-term: Investment securities — 79,883 — 79,883 Total $ 307,300 $ 96,778 $ — $ 404,078 |