PRSS 2017 Annual Report

57 December 31, 2016 Amortized cost Gross unrealized gains Gross unrealized losses Estimated Fair Value Cash and cash equivalents Short-term investments Non-current assets (1) Cash $8,854 $— $— $8,854 $8,854 $— $— Level 1 securities: Money market funds 11,126 11,126 11,126 — — Level 2 securities: Corporate debt securities — — — — — — — Government securities — — — — — — Certificate of deposit 23,808 — — 23,808 — 23,808 — Total $43,788 $— $— $43,788 $19,980 $23,808 $— (1) Restricted cash represents funds set aside and required by the production facility and fulfillment center lease and corresponding escrow agreement negotiated with our landlord. Fair value is a market-based measurement that should be determined based on the assumptions that market participants would use in pricing an asset or liability. The hierarchy level assigned to each security in our available-for-sale portfolio and cash equivalents is based on its assessment of the transparency and reliability of the inputs used in the valuation of such instrument at themeasurement date. The fair value of available-for-sale securities and cash equivalents included in the Level 1 category is based on quoted prices that are readily and regularly available in an active market. The fair value of available-for-sale securities included in the Level 2 category is based on observable inputs, such as quoted prices for similar assets at the measurement date; quoted prices in markets that are not active; or other inputs that are observable, either directly or indirectly. These values were obtained from an independent pricing service and were evaluated using pricing models that vary by asset class and may incorporate available trade, bid and other market information and price quotes from well-established independent pricing vendors and broker-dealers. Because we do not intend to sell the investments that are in an unrealized loss position and it is not likely that we will be required to sell any investments before recovery of their amortized cost basis, we do not consider those investments with an unrealized loss to be other-than-temporarily impaired at December 31, 2017. There were no material other-than-temporary impairments or credit losses related to available-for-sale securities in the years ended December 31, 2017 and 2016, respectively. Therewere nomaterial gross realized gains or losses from the sale of available-for-sale investments in the years endedDecember 31, 2017 and 2016. Realized gains and losses and interest income are included in other income (expense) on the Consolidated Statements of Operations. The following table summarize the short-term investment activity (in thousands): Year Ended December 31, 2017 2016 Proceeds from sale of short-term investments $ — $ — Proceeds from maturities and calls of short-term investments $ 25,792 $ 17,610 Purchases of short-term investments $ 7,995 $ 23,808 Gross realized gains (losses) on sales of short-term investments $ — $ —