76 Stock-Based Compensation We measure and recognize compensation expense for all stock ‑ based awards made to employees, directors and non ‑ employees, based on estimated fair values of the awards on the grant date and recognized using the straight ‑ line method over the requisite service period. The fair value of options is estimated on the grant date using the Black ‑ Scholes option valuation model. The calculation of stock ‑ based compensation expense requires that we make certain assumptions and judgments about a number of complex and subjective variables used in the valuation model, including the expected term, expected volatility of the underlying common stock and risk ‑ free interest rate. Our stock-based awards are subject to either service, performance-based or market- based vesting conditions. We evaluate whether achievement of the performance conditions is probable and record expense over the appropriate service period based on this assessment. Changes in these assumptions can materially affect the fair value and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop. Recent Accounting Pronouncements A description of recently issued accounting pronouncements that may impact our financial position and results of operations is discussed under Note 2 to our consolidated financial statements included in “Part II, Item 8 — Financial Statements and Supplementary Data” of this Annual Report on Form 10-K. ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURE ABOUT MARKET RISK As a “smaller reporting company”, we are not required to provide the information under this item.